MUHLENBERGIINAE (POACEAE: CHLORIDOIDEAE: CYNODONTEAE): FROM NORTHEASTERN MEXICO Paul M. Peterson Department of Botany National Museum of Natural History Smithsonian Institution Washington, DC20013-7012, U.S.A. peterson@si.edu Jesus Valdes-Reyna Departamento de Botdnica Univerisidad Autonoma Agraria "Antonio Narro" Buenavista, Saltillo Coahuila 25315, MEXICO jvaldes@uaaan.mx Yolanda Herrera Arrieta Instituto Politecnico Nacional CIIDIR Unidad Durango-COFAA Durango 34220, MEXICO yherrera@ipn.mx ABSTRACT A taxonomic treatment of the subtribe Muhlenbergiinae for northeastern Mexico (Coahuila, Nuevo Leon, and Tamaulipas) is given. A total of 39 native species are recognized in the study area in four genera: Aegopogon (1), Blepharoneuron (1), Lycurus (2), and Muhlenbergia (35). The names, Muhlenbergia glomerata var. ramosa Vasey and Muhlenbergia spiciformis Trim, are lectotypified. A key for determining the species, descriptions, distributions, specimens examined, illustrations, synonymies, and a brief discussion indicating relationships among all species of Muhlenbergia in northeastern Mexico are provided. RESUMEN Se presenta el estudio taxonomico la subtribu Muhlenbergiinae para el noreste de Mexico (Coahuila, Nuevo Leon y Tamaulipas). En total se reconocen 39 especies nativas en el area de estudio pertenecientes a cuatro generos: Aegopogon (1), Blepharoneuron (1), Lycurus (2), y Muhlenbergia (35). Los nombres, Muhlenbergia glomerata var. ramosa Vasey y Muhlenbergia spiciformis Trin., son lectotipificados. Se incluyen una clave para determinar las especies asi como descripciones, distribuciones, especimenes examinados, ilustraciones y sinonimia para cada especie. Se incluye una breve discusion indicando las relaciones entre todas las especies de Muhlenbergia para el noreste de Mexico. Coahuila, Nuevo Leon, and Tamaulipas or northeastern Mexico covers an area of 291,955 km2 or 15 % of the total land of Mexico. This area includes portions of two natural regions known as the Chihuahuan and Tamaulipan Deserts. These regions are considered a center of origin and diversification of arid and semi-arid plant species (Davila-Aranda et. al. 2004; Peterson et al. 2007). As part of the current revision of the grass flora of northeastern Mexico, an examination of the taxonomy and distribution of the species of subtribe Muhlenbergiinae, was begun to aid the agriculture and livestock industries. This study treats 39 species currently placed in four genera: Aegopogon (1 sp.), Blepharoneuron (1 sp.); Lycurus (2 spp.), and Muhlenbergia (35 spp.). Subtribe Muhlenbergiinae is characterized by having spikelets perfect, staminate or sterile; occasionally with cleistogenes in the leaf sheaths; inflorescence paniculate of spicate main branches or a single raceme; spikelet bearing axis disarticulates falling entire or is persistent; spikelets solitary, paired, or in triplets, occasionally second, l-3(-6)-flowered; glumes awned or unawned, 1-4-nerved; lemmas 3-nerved (rarely 1-nerved), awned or unawned; and a base chromosome number of x = 8-10. An ongoing phylogenetic study of the Muhlenbergiinae based on nuclear and chloroplast DNA sequences is currently in progress (Columbus & Peterson, in prep). In a preliminary analysis, Muhlenbergia appears to be paraphyletic since the remaining nine genera in this subtribe are nested within its clade (Peterson et al. 2001a; 2004; 2007). Subtribe Muhlenbergiinae (Duvall et al. 1994; Peterson 2000; Peterson et al. 1995, 1997, 2001b, 2007) currently consists of 10 genera: Aegopogon with four species; Bealia mexicana Scribn., a monotypic genus J. Bot. Res. Inst. Texas 1 (2): 933 -1000.2007 934 Journal of the Botanical Research Institute of Texas 1(2) from northern Mexico (Peterson 1989; Peterson et al. 1993); Blepharoneuron with two species (Peterson &r Annable 1990, 2003); Chaboissaea with four species, three from central Mexico and C. atacamensis (Parodi) P.M. Peterson & Annable from Argentina and Bolivia (Peterson & Annable 1992; Peterson & Herrera Ar- rieta 1995; Sykes et al. 1997); Lycurus with three species, including the amphitropical disjuncts, L. setosus (Peterson &C Morrone 1997); Muhlenbergia with 147 species centered in northern Mexico and the southwest- ern United States (Herrera Arrieta & Peterson 2007; Peterson 2000, 2003), containing the important range grass M. montana and the amphitropical disjuncts M. arenicola and M. torreyi (Peterson &r Ortiz-Diaz 1997); Pereilema with four species, two from western, central, and southern Mexico; Redfieldia flexuosa (Thurb. ex A. Gray) Vasey, a monotypic genus and southwestern United States endemic of probable hybrid origin; Schaffnerella gracilis (Benth.) Nash, a monotypic genus known only from San Luis Potosi, Mexico (Columbus et al. 2002); and Schedonnardus paniculatus (Nutt.) Trel., a monotypic genus and amphitropical disjunct with spicate primary branches. As currently understood for the New World Chloridoideae, tribes Cynodonteae and Zoysieae are sister, and sister to this clade are members of the Eragrostideae (Columbus et al. 2007; Peterson et al. 2007). All three tribes are supported by DNA sequence data from the chloroplast (matK, trnL-F region) and nuclear (ITS) genomes (Hilu & Alice 2000, 2001; Columbus et al. 2007). Relationships among the ten subtribes within Cynodonteae, as well as the 25 unplaced genera, are uncertain pending additional study. At this point we have no clear idea as to the relationships among these ten Cynodonteae subtribes. However, we do have good molecular support for maintaining the tribe Cynodonteae and morphological support for all of the ten subtribes. The following taxonomic treatment contains a key for determining the species, descriptions, distribution, specimens examined, illustrations, synonymies, and a brief discussion indicating hypothesized relationships among all native and adventive species of Muhlenbergiinae in northeastern Mexico. This study is based on the examination of herbarium specimens from ANSM, ARIZ, B, BA, BAA, BM, CIDIIR, COCA, ENCB, GH, HINT (George S. Hinton's personal herbarium), IBUG, INEGI, K, LE, MEXU, MICH, MO, MSC, NMC, NMSU, NY, P, RSA, SI, SLPM, TAES, TEX, UAT, US, UT, UTC, VT, and W; including the type specimens of most of the species studied. KEY TO THE SPECIES OF MUHLENBERGIINAE IN NORTHEASTERN MEXICO 1. Plants annual. 2. Lemmas unawned. 3. Ligules with lateral lobes extended into auricles; leaf blades with margins and midveins whitish- thickened basally, whitish; primary panicle branches diverging 80-100? from the rachises; pedicels 6-10 mm long, glumes glabrous throughout or obscurely puberulent, the hairs about 0.06 mm long 12. Muhlenbergia fragilis 3. ligules without lateral lobes extended into auricles or rarely with lateral lobes not longer than the body; leaf blades without margins and midveins whitish-thickened; primary panicle branches diverging 25-80? from the rachises; pedicels 2-7 mm long; glumes strigulose near the apex, the hairs 0.1-0.3 mm long 19. Muhlenbergia minutissima 2. Lemmas awned, the awns 3-40 mm long. 4. Spikelets in clusters of three, the central spikelet perfect and the two lateral spikelets pedicellate and staminate or sterile; lemmas usually with lateral nerves extending into awns 1. Aegopogon tenellus 4. Spikelets not in clusters of three, or if in clusters then in pairs; lemmas without lateral nerves extending into awns. 5. Lower glumes 2-nerved, minutely to deeply bifid, the teeth aristate or with awns to 1.3 mm long; spikelets often in sessile-pedicellate pairs; disarticulation at the base of the pedicels; lemmas with awns 6-15 mm long, stiff 8. Muhlenbergia depauperata 5. Lower glumes 1-nerved or unnerved, not bifid, unawned or with a single mucro or awn; spikelets borne singly; disarticulation above the glumes; lemmas with awns 10-40 mm long, delicate, straight toflexuous. 6. Glumes 1.2-2.8 mm long, acute to acuminate; upper glumes 1.5-2.8 mm long 34. Muhlenbergia tenuifolia Peterson et al., Muhlenbergiinae from northeastern Mexico 935 6. Glumes 0.3-1.3 mm long, obtuse to acute; upper glumes 0.5-1.3 mm long. 7. Cleistogamous panicles with 1-3 florets present in the axils of the lower sheaths; panicles open and not densely flowered, 1 -6.5 cm wide; primary branches diverging up to 80? from the rachises; ligules truncate to obtuse 18. Muhlenbergia microsperma 7. Cleistogamous panicles absent in the axils of the lower sheaths; panicles narrow, contracted, 0.6-2.8 cm wide; primary branches spreading up to 30? from the rachises; ligules acuminate 32. Muhlenbergia spiciformis 1. Plants perennial. 8. Plants rhizomatous, rhizomes often stout, scaly, and creeping. 9. Upper glumes always 3-nerved, the apex usually with 2-4 small teeth; old sheaths flattened, ribbon-like or papery, sometimes spirally coiled. 10. Glumes greenish-plumbeous, the surface scabrous, usually with a few short hairs below; pan- icles 0.5-2 cm wide, the primary branches appressed to spreading up to 30? from the rachises 25. Muhlenbergia quadridentata 10. Glumes whitish, stramineous or grayish-green sometimes with plumbeous mottles, the surface shiny, usually glabrous to rarely scabrous below; panicles 0.5-6 cm wide, the branches appressed to spreading up to 45? from the rachises 38. Muhlenbergia virescens 9. Upper glumes usually 1 -nerved or sometimes 2- or 3-nerved, but the apex never toothed; old sheaths occasionally flattened. 11. Lemmas awned, the awns 1 -20(-25) mm long; anthers orange. 12. Lemma awns 0.1-3(-5) mm long, straight; leaf sheaths longerthan the internodes 13. Muhlenbergia glauca 12. Lemma awns 10-20(-25) mm long, flexuous; leaf sheaths mostly shorter than the internodes 21. Muhlenbergia polycaulis 11. Lemmas unawned or mucronate, the mucros to 1 mm long; anthers yellow, purple, greenish or reddish. 13. Panicles narrow to open, 4-16 cm wide. 14. Panicle branches densely flowered, not capillary, tightly appressed or loosely spreading up to 40? from the rachises at maturity; paleas densely pubescent to villous between the nerves and along the margins on proximal 2/3 to % 15. Muhlenbergia jaime-hintonii 14. Panicle branches capillary, diverging 30-90(-100)? from the rachises at maturity; paleas glabrous. 15. Ligules 0.5-2 mm long, hyaline, with well-developed lateral lobes or auricles; blade margins and midveins prominent, whitish, thickened 5. Muhlenbergia arenacea 15. Ligules 0.2-1 mm long, ciliate, without lateral lobes or auricles; blade margins and midveins not conspicuously thickened, greenish 7. Muhlenbergia asperifolia 13. Panicles contracted, narrow, 0.1-3.9 cm wide. 16. Spikelets 1.4-2.4 mm long. 17. Culms 44-82 cm tall; leaf blades 5-22 cm long, 1.8-5 mm wide; panicles 13-34 cm long 15. Muhlenbergia jaime-hintonii 17. Culms 4-30 cm tall; leaf blades 0.2-1.8 mm wide; panicles 1 -5 cm long. 18. Lemmas and paleas glabrous or with minute appressed pubescence, the hairs about 0.1 mm long; leaf sheaths 0.3-2.4 cm long; panicles partially included in the upper sheaths; ligule apices truncate 36. Muhlenbergia utilis 18. Lemmas and paleas densely villous, the hairs less 0.4-1 mm long; leaf sheaths 5-15 cm long; panicles usually on an exserted peduncle; ligules apices acute 37. Muhlenbergia villiflora var. villiflora 16. Spikelets 2.4-8 mm long. 19. Glumes 3-8 mm long (including the awns), 1.3-2 times longer than the lemma; leaf blades 2-5 mm wide, flat; anthers 0.4-0.8 mm long 26. Muhlenbergia racemosa 19. Glumes 1.1-3.6 mm long, Vi to as long as the lemma; leaf blades 0.5-2.6 mm wide, flat to involute; anthers 0.7-2.4 mm long. 20. Lemmas with tawny hairs up to 0.6 mm long on the lower Vi along the midveins and margins; leaf blades 4-12 cm long, not arcuate; anthers 1.8-2.4 mm long, orange 13. Muhlenbergia glauca 20. Lemmas glabrous or with minute appressed pubescence along margin and base, the hairs less than 0.1 mm long; leaf blades 0.4-6 cm long, somewhat arcuate spreading; anthers 0.7-1.4 mm long, yellow to purplish 27. Muhlenbergia repens 936 Journal of the Botanical Research Institute of Texas 1(2) 8. Rhizomes absent. 21. Upper glumes 3-nerved; old sheaths flattened and sometimes spirally twisted near base. 22. Upper glumes 3-toothed and 3-awned, the teeth (including the awns) 1/3 to Vi the length of the glume, and the awns up to 1.7 mm long 20. Muhlenbergia montana 22. Upper glumes 2-4-toothed, the teeth small and unawned, less than 1/6 the length of the glume. 23. Glumes greenish-plumbeous, the surface scabrous, usually with a few short hairs below; panicles 0.5-2 cm wide, the primary branches appressed to spreading up to 30? from the rachises 25. Muhlenbergia quadridentata 23. Glumes whitish, stramineous or grayish-green sometimes with plumbeous mottles, the surface shiny, usually glabrous below; panicles 0.5-6 cm wide, the branches appressed to spreading up to 45? from the rachises 38. Muhlenbergia virescens 21. Upper glumes usually 1-nerved (rarely 2-or 3-nerved); old sheaths usually not flattened or spirally twisted near base. 24. Panicles wide, open, loosely contracted to diffuse, (2-)3-20 cm wide; panicle branches usually widely spreading to loosely ascending. 25. Lemmas unawned, mucronate (mucros < 1 mm long), or awned, with awns 1 -4 mm long. 26. Culms (65-)80-230(-300) cm tall; leaf blades 20-100 cm long, 2-7 mm wide, flat or folded. 27. Leaf sheath auricles absent; ligules 10-25 mm long; lemmas pubescent along the midvein and margins on lower >2-% 11. Muhlenbergia emersleyi 27. Leaf sheath auricles present (?1)2?4(?10) mm long, linear subulate to broadly tri- angular, longer above, straight or twisted, firm below; ligules 2-10(-12) mm long; lemmas glabrous or pubescent with scattered hairs on lower Vi 30. Muhlenbergia robusta 26. Culms 10-70 cm tall; leaf blades 1-16 cm long, 0.3-2.5 mm wide, filiform, involute, flat or folded. 28 Lemmas unawned; spikelet pedicels flexuous nodding to reflexed; lemmas with a thick covering of tawny to shiny silky hairs located on the midvein and margins; paleas densely villous between the nerves 2. Blepharoneuron tricholepis 28. Lemmas with awns 0.5-4 mm long; spikelet pedicels erect, not flexuous nodding to reflexed; lemmas without a thick covering of tawny to shiny silky hairs on the midvein and margins but with appressed pubescence, the hairs scattered; paleas sparsely pubescent between the nerves. 29. Leaf blades not arcuate, 1 -2.2 mm wide, 4-10(-16) cm long; 1 or more culm nodes exposed; leaf blades reaching VA-VI of the plant height 6. Muhlenbergia arenicola 29. Leaf blades arcuate, 0.3-0.9 mm wide, 1-3(-5) cm long; usually no culm nodes exposed; most leaf blades reaching no more than 1/5 of the plant height 35. Muhlenbergia torreyi 25. Lemmas awned, with awns 5-30(-40) mm long. 30. Plants conspicuously branched, especially from the middle and lower nodes, loosely caespitose; culms decumbent, geniculate, or erect. 31. Plants distinctly bushy in appearance; plants perennials with a wirey and knotty base; panicles 6-15 cm wide; anthers 1.5-2.3 mm long; caryopses ellipsoid, compressed, yellowish brown 22. Muhlenbergia porteri 31. Plants not distinctly bushy in appearance; plants short-lived perennials to annuals with delicate bases; panicles 1-6.5 cm wide; anthers 0.9-1.5 mm long; caryopses narrowly fusiform, terete, brownish 34. Muhlenbergia tenuifolia 30. Plants not conspicuously branched, caespitose; culms erect to rarely slightly decumbent near base. 32. Basal leaf sheaths compressed-keeled or flattened; glumes longer, as long or a little shorter than the lemma. 33. Leaf sheath auricles present 0.4-2.6 cm long on lower portions and up to 6.4 cm long above; lemmas glabrous or margins pubescent on the lower 1/3, rarely the lower 1/3 with scattered hairs; glumes usually with faint, widely scattered hairs, the hairs less than 0.1 mm long 9. Muhlenbergia distichophylla 33. Leaf sheath auricles absent; lemmas pubescent along the midvein and margins on the lower V2-%; glumes without widely scattered hairs 11. Muhlenbergia emersleyi Peterson et al., Muhlenbergiinae from northeastern Mexico 937 32. Basal leaf sheaths terete; glumes usually much shorter than the lemma. 34. Spikelets 3.5-5.1 mm long; lemmas 3.5-5.1 mm long; paleas 3.5-5.1 mm long. 35. Lemmas scaberulous to scabrous, not smooth and shining, purple; leaf blades 1-3 mm wide, flat or involute, not falcate; culms usually with a single node; anthers purplish 29. Muhlenbergia rigida 35. Lemmas glabrous, smooth and shining, stramineous; leaf blades 0.2-1.2 mm wide, tightly involute, falcate; culms usually with 2-4 nodes; anthers greenish 31. Muhlenbergia setifolia 34. Spikelets (2-)24-3.6 mm long; lemmas 2.3-3.6 mm long; paleas (2-)2.4-3.6 mm long. 36. Culms 25-60 cm tall; leaf blades 5-13 cm long, falcate; lemmas purplish and short pilose; paleas short pilose between the nerves; anthers 1.6-2 mm long; caryopses 1 -1.2 mm long, fusiform to ovoid 24. Muhlenbergia purpusii 36. Culms 74-150 cm tall; leaf blades 20-65 cm long, not falcate; lemmas dark green and glabrous; paleas glabrous between the nerves; anthers 1.1 -1.6 mm long; caryopses 1.5-1.7 mm long, fusiform 33. Muhlenbergia stricta 24. Panicles narrow, contracted to loosely contracted, and or spikelike 0.2-3 cm wide; panicle branches usually closely appressed to loosely spreading. 37. Panicles spikelike, 0.2-1.2 mm wide, densely flowered, sometimes interrupted near base; primary branches tightly appressed, the branches 0.1-4 cm long. 38. Culms (35-)50-200 cm tall; panicles 15-60 cm long; leaf sheaths rounded near base. 39. Lemmas awned, the awns 10-20 mm long; leaf blades 0.5-1.5 mm wide, tightly involute, falcate, and densely pubescent above; glumes puberulent on upper 2/3 14. Muhlenbergia gypsophila 39. Lemmas mucronate,themucro less than 1 mm long; leaf blades 1.5-6 mm wide, flat or involute, never falcate, and without hairs above; glumes without hairs, scabrous. 40. Glumes 3.4-5.6 mm long, usually longer than the lemma, apex unawned and not mucronate; ligules (5-)8-40(-50) mm long; anthers 1.5-2.2, dark greenish 17. Muhlenbergia macroura 40. Glumes 1.8-3.2 mm long, shorter than the lemma, apex sometimes mucronate or short-awned, the awn up to 1.7 mm long; ligules 0.5-2(-3) mm long; anthers 1.3-1.8 yellow to purple 28. Muhlenbergia rigens 38. Culms 15-60 cm tall; panicles (2-)4-16 cm long; leaf sheaths compressed-keeled near base. 41. Lower glumes 2-or 3-nerved and awned, the awns 1-5 mm long; spikelets paired on a branch, the lower spikelet staminate or sterile and the upper spikelet bisexual. 42. Upper leaf blades acute sometimes with a narrow bristle 0.5-3 mm long; ligules 1.5-3 mm long, usually with triangular lateral lobes 0.5-2.5 mm long; culms erect to decumbent 3. Lycurus phleoides 42. Upper leaf blades acuminate with slender awn-like seta 3-8(-10) mm long; igules (2-)3-12 mm long, sometimes with lateral lobes the same length as the igule; culms erect 4. Lycurus setosus 41. Lower glumes all 1-nerved, unawned or mucronate, the mucros 0.5-1 mm long; spike- lets borne singly on a branch, or if in pairs, the upper and lower spikelets both bisexual. 43. Lemmas awned, the awns 10-20 mm long; spikelets 3.5-4.3 mm long, stra- mineous to purplish; glumes 1.2-2.5 mm, the apex acute often erose, not mucronate; lemmas with distinct, raised lateral nerves 14. Muhlenbergia gypsophila 43. Lemmas mucronate, the mucros 0.5-1 mm long; spikelets 2-3 mm long, dark green or plumbeous; glumes 0.5-1.6 mm long, apex acute to obtuse and mucronate, the mucros 0.5-1 mm long; lemmas without distinct, raised latera nerves 39. Muhlenbergia wrightii 37. Panicles narrow, (0.6-)1-3 cm wide, loosely contracted to narrowly open; primary branches loosely appressed to spreading up to 70? from the rachises, the branches 0.4-8.5 cm long. 44. Lemmas unawned, mucronate (mucros < 1 mm long), or awned, the awns 1-6 mm long. 45. Spikelet pedicels flexuous nodding to reflexed, capillary; lemmas with a thick covering of tawny to shiny silky hairs located on the midvein and margins; ligules (0.3-)0.7-2(2-2.7) mm long, hyaline to opaque throughout 2. Blepharoneuron tricholepis 938 Journal of the Botanical Research Institute of Texas 1(2) 45. Spikelet pedicels erect, notflexuous nodding to reflexed or capillary; lemmas without a thick covering of tawny to shiny silky hairs on the midvein and margins but without hairs, puberulent throughout or densely vilbus on the margins below; ligules 4?35 mm long, firm below and often brownish. 46. Spikelets 3.8-5 mm long; basal leaf sheaths terete; anthers 1.5-2.2 mm long,gree- ish; ligules notdecurrentand brownish below 10. Muhlenbergia dubia 46. Spikelets 2.4-3.5 mm long; basal leaf sheaths compressed-keeled or flattened; anthers 1.1-1.6 mm long, yellowish or purplish; ligules deccurent, brownish below. 47. Glumes longer than the florets, glabrous and without hairs, scabrous or smooth; lemmas glabrous, scabrous or smooth, rarely puberulent; ligules 10-35 mm long 16. Muhlenbergia lindheimeri 47. Glumes shorter than the florets, pubescent especially near the base; lem- mas villous on the lower V2, and margins below; ligules 5-13 mm long 23. Muhlenbergia pubigluma 44. Lemmas awned, the awns 10-40 mm long. 48. Glumes 0.3-1.1 mm long, < Vi as long as the lemma, apices obtuse to acute. 49. Culms usually with a single basal node; ligules 4-10 mm long, decurrent, firm and brownish below; glumes puberulent on the upper 2/3; lemmas short pilose throughout, 2.3-3.1 mm long, apices acute; lemma awns 10-20 mm long; anthers 1.6-2 mm long; caryopses 1-1.2 mm long 24. Muhlenbergia purpusii 49. Culms with 4-8 nodes; ligules 1-3 mm long, not decurrent and firm and brown- ish below; glumes glabrous; lemmas sparsely appressed-pubescent on the lower 14,2.8-4 mm long, apices acuminate; lemma awns (10-)20-40 mm long; anthers 0.9-1.6 mm long; caryopses 2-2.6 mm long 32. Muhlenbergia spiciformis 48. Glumes (1-) 1.2-2.8 mm long, > Vi as long as the lemma (at least the upper glume), apices acute to acuminate. 50. Culms stigulose below the nodes; anthers 1.5-2 mm long, orange; lemmas elliptic, widest near the middle 21. Muhlenbergia polycaulis 50. Culms scaberulous below the nodes; anthers 0.9-1.5 mm long, yellowish; le- mas lanceolate, widest near base 34. Muhlenbergia tenuifolia Aegopogon Humb. & Bonpl. exWilld., Sp. PI. 4(2):899. 1806. TYPE: Aegopogon cenchroides Humb. & Bonpl. ex Willd. Slender annuals or perennials, caespitose to sprawling, occasionally with stolons; hermaphrodites or func- tionally andromonoecious. Culms 2-55 cm tall, erect, geniculate or decumbent, herbaceous; internodes hollow. Leaf sheaths open; ligules membranous; blades flat. Inflorescences terminal, open to somewhat contracted, racemelike, 1-sided panicles; each branch with 3 spikelets; disarticulation at the base of the branches. Spikelets 1-flowered; lateral spikelets pedicellate, staminate or sterile, sometimes rudimentary; central spikelets nearly sessile or short-pedicellate, laterally compressed, perfect; glumes shorter than the florets, equal, 1-nerved; lemmas membranous, 3-nerved, the central and lateral nerves usually extending into awns; paleas 2-nerved, the nerves usually extending into awns; lodicules 2; ovary glabrous, styles free to their bases, stigmas 2; stamens 3. Caryopses fusiform to ellipsoid, laterally compressed. Chromosome number x = 10. Four species, three in Mexico and one endemic to South America. Etymology.?Name from the Greek aix, 'goat', and pogon, 'beard', alluding to the many awns of the spikelets. Comments.?fn a preliminary molecular analyses all species currently placed in Aegopogon fall into a "Muhlenbergia subg. Muhlenbergia" clade that has anatomical characteristics consistent with PCK (phospho- enolpyruvate carboxykinase) subtype of C. photosynthesis (Peterson 2000; Peterson et al. 2001b, 2004; Peterson &Herrera Arrieta2001; Columbus &r Peterson, in prep.). Anatomical features of this clade include: loosely arranged chlorenchyma with tabular cells that are indistinctly radiate and continuous between the vascular bundles [PCK subtype, defined as centrifugal/evenly distributed photosynthetic carbon reduction (PCR) cell chloroplasts (with grana), XyMS+ and presence of PCR cell wall suberized lamella, in Hattersley and Watson's (1992) sense], shield-shaped (narrower than deep) central bulliform cells, and primary vascular bundles with non-sclerosed phloem (Peterson &C Herrera Arrieta 2001). Peterson et al., Muhlenbergiinae from northeastern Mexico 939 1. Aegopogon tenellus (DC.) Trin., Gram. Unifl. Sesquifl. 164. 1824. (Fig. 1, A & B). Lamarckia tenellaDC, Cat. PL Horti Monsp. 120. 1813. TYPE: Cultivated at Montpellier, De Candolle s.n. (HOLOTYPE: MPU?; ISOTYPE: US-75926 fragm!.). Hymenothecium unisetum Lag., Gen. Sp. PL 4. 1816. Aegopogon unisetus (Lag.) Roem. & Schult., Syst. Veg. 2:805. 1817. Aegopogongemini- Jloius var. unisetus (Lag.) E. Fourn., Mexic. PL 2:71. 1886. TYPE: MEXICO: cultivated from seed, D. Sesse s.n.(HOLOTYPE: MA). Aegopogon gracilis Vasey, Bull. Torrey Bot. Club 13(12):230. 1886. TYPE: MEXICO. CHIHUAHUA: Aug 1885-Nov 1885, E. Palmer 28 (HO- LOTYPE: US-75305!). Aegopogon geminijlorus var. abortivus E. Foum., Mexic. PL 2:71. 1886. TYPE: MEXICO. VERACRUZ: Orizaba, 1864, Weher & Thomas s.n. (SYNTYPE: P; ISOSYNTYPE: US-75961 fragm. ex P!). Escamela, M. Bourgeau 750 (SYNTYPE: P; ISOSYNTYPE: US-75303 fragm!). VERACRUZ: Orizaba, Botteii 41 (SYNTYPE: P). Orizaba, M. Botteii & A.L. Sumicrast 84 (SYNTYPE: P). SAN LUIS POTOSI: Sep 1877, Schajjner 7 (SYNTYPE: P; ISOSYNTYPE: GH). Aegopogon geminijlorus subvar. purpureus Griseb. exE. Fourn., Mexic. PL 2:71. 1886. TYPE: MEXICO. DISTRITO FEDERAT: Tacubaya, Sehaffner 168a (SYNTYPE: P, ISOSYNTYPE: US-75962!). PANAMA. Seemann s.n. (SYNTYPE: K). Aegopogon cenchroid.es var. abortivus E. Fourn., Mexic. PL 2:72. 1886. Aegopogon tenellus var. abortivus (E. Fourn.) Beetle, Univ. Wyoming Publ. 8(2):19. 1948. TYPE: MEXICO. Veracruz: M. Botteii &? A.L. Sumicrast 1187 (HOLOTYPE: P!; ISOTYPE: US-75949 fragm. ex P!). Aegopogon imperfectus Nash, N. Amer. Fl. 17(2):138. 1912. TYPE: MEXICO. CHIHUAHUA: Arroyo Aucho, Sierra Madre, cool mossy ledges, 15 Oct 1887, C.G. Pringle 1408 (HOLOTYPE: NY; ISOTYPE: US-740860!). Slender often sprawling, caespitose annuals. Culms (2-) 6-30 cm tall, glabrous below the nodes; internodes 0.6-6 cm long, glabrous to pilose. Leaf sheaths mostly 0.5-4.8 cm long, shorter than the internodes, gla- brous to sparingly pilose; ligules 0.6-1.5 mm long, apex mostly truncate, lacerate; blades 1.5-6 cm long, 0.5-1.5(-1.7) mm wide, flat, scaberulent and pubescent above, smooth beneath. Panicles 2-6 cm long, 0.5-1.2 cm wide, open, loosely-flowered, racemose primary branches 2-4 mm long, excluding the awns, one per node. Spikelets 1.5-3.2 mm long, often greenish or purplish, the clusters with one short-pedicelled spikelet (bisexual), the pedicels 0.2-0.6 mm long and the other two spikelets (staminate or sterile) short- pedicelled, the pedicels about 0.7-1.5 mm long; glumes (1?)1.3?2 mm long, oblong and wider distally, apex deeply notched, entire or mucronate, the mucro 0.2-1 mm long, lobes obtuse; lemmas 2.5-3.2 mm long, 3-awned, the central awns 3?8(?11) mm long, lateral awns usually 0.2-2 mm long or missing; paleas 2.2-3 mm long, puberulent, apex 2-mucronate, the mucros less than 0.8 mm long; anthers 0.5-0.8 mm long, yellowish. Caryopses 1.1?1.3 mm long, obovoid, light brownish. 2n = 20, 60. Phenology.?Flowering August through November. Distribution and habitat.?Moist slopes, cliffs, barrancas, canyons, roadsides, and along or near springs usually in shaded areas associated with Pinus spp., Quercus spp., Salvia sp., Ceanothus sp., Juniperus spp., Arbutus sp., Holodiscus sp., and Acacia spp.; 1300-2860 m. Aegopogon tenellus ranges from southern Arizona throughout most of Mexico and Central America. Specimens examined. MEXICO. Tamaiilipas: Municipio de Gomez Farias, Ejido San Jose, M.E. Crespo-Ovalle 523 (ANSM). Nuevo Leon: Municipio de Galeana, km 12 carr. Galeana-Zaragoza, G. Armienta 938 (ANSM). Blcpharonciiron Nash, Bull. Torrey Bot. Club 25: 88. 1898. TYPE: Blepharoneuron tricholepis (Torr.) Nash. Caespitose perennials and slender annuals, much branched near base, rhizomes absent. Culms 10-70 cm tall, hollow, occasionally pithy, scaberulous to strigose below the nodes. Leaf sheaths open, glabrous, usually longer than the internodes; ligules membranous or hyaline, truncate to obtuse often lacerate, the margins entire, decurrent; blades flat to involute, short pubescent above, glabrous to scabrous below. Inflorescences open or often somewhat contracted panicles with ascending to spreading branches; the pedicels often capil- lary, wiry and flexuous or nodding to reflexed, minutely granular just below the spikelet. Spikelets 1-flow- ered, slightly compressed, disarticulating above the glumes; glumes subequal, ovate to obtuse, occasionally lanceolate, faintly 1-nerved, grayish-green (olivaceous), glabrous; lemmas 3-nerved, firmer than the glumes and slightly longer, lanceolate, grayish-green, with densely appressed, tawny to shiny silky hairs located on the midvein and margins, the apex acute to obtuse, occasionally mucronate; paleas about same length as lemmas or slightly longer, 2-nerved, densely villous between the nerves; lodicules 2, club-shaped, truncate, the lateral margins thin; stamens 3; styles not at all united at the base; stigmas plumose. Caryopses fusiform to ellipsoid, brownish. Chromosome number x = 8. Two species in Mexico, one of these endemic. 940 Journal of the Botanical Research Institute of Texas 1(2) FIG. ~\.Aegopogon tenellus [F.W. Gould 10391 (TAES, US)]. A. Habit B. Panicle branch with three spikelets, central spikelet bisexual (perfect) and the two lateral spikelets staminate or sterile. Muhlenbergia arenacea [P.M. Peterson 5703 & C.R. Annable (US)]. C. Habit. D. Ligule. E. Glumes. F. Florets. G. Lodicules, stamens, and pistil. Peterson et al., Muhlenbergiinae from northeastern Mexico 941 Name from the Greek blepharis, 'eyelash', and neuron, 'nerve', a reference to the silky hairs located on the margins and midvein. Comments.?In a preliminary molecular analyses Blephawneuron tricholepis and B. shepherdii are sister, or are within a grade that includes Muhlenbergiafiliformis (Thurb. ex S. Watson) Rydb., M. ligularis (Hack.), and M. vaginata Swallen (Peterson et al. 2001b, 2004; Columbus & Peterson, in prep.). 2. Blcpharoncm-on tricholepis (Torr.) Nash, Bull. Torrey Bot. Club 25:88. 1898 (Fig. 2, A-J). Vilfa tricholepis Torr., Pacif. Railr. Rep. 4(5):155. 1857. Spomholus tricholepis (Torr.)J.M. Coult., Man. Bot. Rocky Mt. 411. 1885. TYPE: U.S.A. NEW MEXICO. Bernadillo Co.: Sandia Mountains, 10 Oct 1853, Bigelow s.n. (LECTOTYPE: NY! designated by Peterson & Annable, Syst. Bot. 15:522. 1990; ISOLECTOTYPE: MO!) Densely tufted, caespitose perennials. Culms 10-70 cm tall, 0.3-0.7 mm diameter just below the inflores- cence, glabrous to scabrous just above and below the nodes, slender, erect; internodes 1.2-10 cm long. Leaf sheaths 1.8-9.5 cm long, usually glabrous, crowded near base, the margins glabrous, occasionally scabrous, whitish, shorter or longer than the internodes; ligules (0.3?)0.7?2(?2.7) mm long, hyaline to opaque, truncate to obtuse, the margins entire, decurrent, the apex erose-dentate to finely ciliate and irregularly toothed; blades 1-15 cm long, 0.6-2.5 mm wide, filiform, involute, arcuate, scabrous above and below, the midvein evident, raised on the abaxial surface. Panicles 3-25 cm long, 1-10 cm wide, a narrow or open panicle with ascending primary branches spreading 0-50? from the rachises; primary branches 1-6 cm long, 1-3 per node; pedicels 2-9 mm long, slender, capillary, minutely granular just below the spikelet, flexuous nod- ding to reflexed; nodes per panicle 5-25. Spikelets 2.3-3.4(-3.8) mm long, grayish-green; glumes nearly equal to subequal in length, grayish-green (olivaceous) and occasionally purplish tinged, glabrous, ovate to oblong-elliptical, the apex obtuse to acute often irregularly toothed; lower glumes (1.5?)1.8?2.6(?3) mm long; upper glumes (1.7?)2?3.2(?3.7) mm long, broader and often appearing 3-nerved by its characteristic folding, however, only the midvein contains a vascular trace; lemmas (2?)2.3?3.4(?3.8) mm long, lanceolate, grayish-green (olivaceous), often purplish tinged; apex acute to obtuse with a thick covering of appressed to spreading tawny to shining silky hairs on the midvein and margins, the hairs up to 1.2 mm long; pa- leas (2?)2.2?3.5(?3.9) mm long, densely villous between the nerves; anthers 1.2-2.1 mm long, brownish. Caryopses 1.2-1.4 mm long, fusiform to elliptic, the embryo with a dorsal ridge extending 2/3 of the grain, light brownish. 2n = 16. Phenology.?Flowering mid August through November. Distribution and habitat.?Dry rocky to sandy slopes, canyon walls, rock outcrops, dry meadows, and open woods in pine-oak-madrone forests with Arctostaphylos spp., pinyon-juniper woodlands, spruce-fir forests with Ceanothus sp., Cupressus sp., and Cornus stolonifera, aspens groves, and pine woodlands with Artemisia and Garrya; central Mexico north throughout the Sierra Madre Occidental, Sierra Madre Oriental, and through the Rockies to Utah and Colorado, U.S.A. (Peterson & Annable 1990); 700-3660 m. Specimens examined. MEXICO. Coahuila: Municipio de Arteaga, 4 km N de Las Vigas, R. Banda-Silva s.n. (ANSM); Las Vigas, Canon de Jame, Sierra de Arteaga, J.A. Villarreal Q. 1794, M.A. Canunzcl P. &J. Valdes-Reyna (ANSM); Municipio de Muzquiz, Madera del Carmen, Wooded canyon above Campo El Dos, P.M. Peterson 18908 &]. Valdes-Reyna (US). Nuevo Leon: 11.4 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13335 &> M.B. Knowles (US); 17.5 mi W of Dieciocho de Marzo on summit of Cerro Potosi, P.M. Peterson 13355 & M.B. Knowles (US); Municipio de Aramberri, Cerro El Viejo, G.S. Hinton 23968 (ANSM, MEXU, TEX); Municipio de Galeana, Sierra Madre Oriental: ascent of Infernillo, 15 mi SW of Galeana, C.H. Mueller & M. T. Mueller 926 (MEXU, TEX); Municipio de General Zaragoza, Pena Nevada, M.H. Cervera-Rosado 336 (COCA). LyCUrUS Kunth, Nov. Gen. Sp. 1:141. 1816. TYPE: Lycurus phleoides Kunth, (LECTOTYPE: designated by Hitchc. U.S.D.A. Bull. 722:139. 1920). Caespitose perennials; rhizomes absent. Culms 10-60 cm tall, erect or decumbent, usually branched. Leaf sheaths open above, laterally compressed; ligules membranous to hyaline, decurrent; blades flat or folded, margins prominent. Inflorescences contracted spikelike panicles, terminal and axillary; each branch with a pair of unequally pedicellate spikelets or a pedicellate spikelet and a short secondary branch bearing two spikelets; disarticulation at the base of the pedicels or branch, the paired spikelets falling as a unit. Spikelets 942 Journal of the Botanical Research Institute of Texas 1(2) FIG. 2. Blepharoneuron tricholepis [P.M. Peterson 5567& C.R. Annable (US)]. A. Habit. B. Ligule. C. Panicle. D. Spikelet. E. Glumes. F. Floret. G. Floret. H. Palea. I. Lemma, ventral view. J. Lodicules, stamens, and pistil. Peterson et al., Muhlenbergiinae from northeastern Mexico 943 1-flowered; usually the lower spikelet in each pair staminate or sterile and the upper spikelet bisexual; glumes subequal, awned, 1-or 2(3-)-nerved; lower glumes usually 2-nerved, 2-awned; upper glumes l(2-)-nerved, l(2-)-awned; lemmas membranous, 3-nerved, lanceolate, puberulent along the margins, apices awned, the awn usually shorter than the lemma; paleas about as long as the lemmas, apex acute, sometimes the nerves extending as two mucros, margins hyaline; stamens 3. Caryopses fusiform. Chromosome number x = 10. Name from the Greek lykos, 'wolf, and oura, 'tail', a reference the the spikelike inflorescence. Comments.?Possession of paired spikelets and 2-nerved lower glumes that are 2-awned, although not common within the Muhlenbergiinae, is not unique to Lycurus. Muhlenbergia brevis and M. depauperata exhibit morphological features that suggest a close relationship with Lycurus. Mez (1921) indicated a rela- tionship with Lycurus when he transferred M. shaffneri E. Fourn., considered a synonym of M. depauperata, to Lycurus. Muhlenbergia brevis and M. depauperata share many morphological features with Lycurus, most importantly: spikelets borne in pairs and lower glumes that are 2-nerved and 2-awned (Peterson 2000). Schaffnerella gracilis is apparently sister to the three species of Lycurus for trnL-F and ITS sequence analyses, and this Lycurus-Schaffnerella clade is found in a well-supported trnL-F-derived clade that includes M. wrightii, all four species of Chaboissaea, and Schedonnardus paniculatus (Peterson et al. 2004; Columbus & Peterson, in prep.). Allozyme studies were useful is determining the biogeographical history of the amphitropical Lycurus setosus and it seems likely that this species has recently dispersed to South America because populations there contain less genetic variation (Peterson &r Morrone 1997; Peterson 2000). 3. Lycurus phleoides Kunth, Nov. Gen. Sp. (quarto ed.) 1:142, pi. 45. 1816. (Fig. 3, A & B). TYPE: MEXICO: inter Guanaxuato et Temascatio et in radicibus aridissimi montis La Buffa, alt. 1030 hexap., Sep, EW.H.A. Humboldt &> A.J.A. Bonplancl s.n. (HOLOTYPE: PI; ISOTYPES: BAA-fragm.!, US-610840 fragm. ex P-Bonpl!, US-610841 tragm.Q. Loosely caespitose perennials. Culms 20-60 cm tall, erect to decumbent at base, scabrous to puberulent just above or below the nodes. Leaf sheaths usually 0.5-3 cm long, glabrous to pubescent, compressed-keeled near base; ligules 1.5-3 mm long, acuminate and erose, usually with triangular lateral lobes 0.5-2.5 mm long, the lateral lobes decurrent below; blades 2-8 cm long, 1?1.5 mm wide, flat or folded, glabrous to puberulent below and puberulent to hispidulous above, margins and midvein whitish-thickened, apex acute or some- times with a narrow bristle 0.5-3 mm long on the upper blades. Panicles (2-)4-10 cm long, 4-8 mm wide, contracted, narrow, densely flowered, and spikelike; primary branches 0.1-0.3 cm long, tightly appressed. Spikelets 3-4 mm long, l-flowered; glumes 1-2 mm long, scaberulous near apex, awned, the awns 1-5 mm long; lower glumes usually 2(3-)-nerved; upper glumes l(2-)-nerved, awns 2-5 mm long; lemmas 3-4 mm long, puberulent along the margins, awned, the awns 1-3 mm long; paleas 3-4 mm long, puberulent between the nerves; anthers 1.5-2 mm long, yellow. Caryopses 1.8-2.2 mm long, brownish. In = 40. Phenology.?Flowering July through October. Distribution and habitat.?Rocky slopes, canyons, bajadas, and flats often occurring in calcareous soils and associated with Quercus gregii, Larrea tridentata, Pinus cembroidesjuniperusflaccida, Salvia regla, Cowania plicata, Bouteloua gracilis, B. unijlora, Dasylirion longissimum, Y. carnerosana, Agave lecheguilla, Jatropa dioica, Muhlenbergia spp., Berberis sp., Opuntia spp, Selaginella sp, Hechtia sp., Brahea sp., and Mimosa sp.; northern and central Mexico in Aguascalientes, Chihuahua, Distrito Federal, Durango, Guanajuato, Hidalgo, Jalisco, Mexico, Michoacan, Morelos, Nayarit, Oaxaca, Puebla, Queretaro, San Luis Potosi, Sonora, Tlaxcala, and Zacatecas to southwestern U.S.A. in Texas and New Mexico (Espejo Serna et al. 2000; Peterson et al. 2001b; Powell 1994; Reeder 1985; Sanchez & Rugolo de Agrasar 1986); 1200-2500 m. Specimens examined. MEXICO. Coahuila: Sierra El Pino, 9.6 km SW of Rancho El Cimarron, P.M. Peterson 10635 & C.R. Annable (US); 33.5 km W of Rancho El Cimarron, P.M. Peterson 10656 & C.R. Annable (US); 5 mi W of Chapultepec, P.M. Peterson 13278 & M.B. Knowles (US); 30.6 km SE of Saltillo on HWY 57 towards San Luis Potosi, P.M. Peterson 6240 & C.R. Annable (US); 6 km S of Saltillo, P.M. Peterson 8347 &>J. Valdes-Reyna (US); 35.4 kmW of Ocampo at Cuesta Zozaya, P.M. Peterson 8367 &>]. Valdes-Reyna (US); western base of Picacho delFuste, I.M.Johnston 8444 (US); Vicinity of La Noria, R.M. Stewart 1210 (US); Municipio de Acuna, del Carmen Mountains, E.G. Marsh Jr. 658 (MEXU); Lomas calizas cerca de Santo Domingo, no collector (MEXU); Municipio de Arteaga, 2 km NW of Ejido Sierra Hermosa. R. Lopez Aguillon s.n. (ANSM); Sierra Zapaliname, at 2 kmE of Saltillo up Camino de Quatro (Las Palapas), P.M. Peterson 17858, J. Valdes- 944 Journal of the Botanical Research Institute of Texas 1(2) 1mm FIG. i.Lycurusphleoides. A. Habit. B. Ligule. Lycurussetosus [P.M. Peterson 11724&C.R. Annable (US)]. C. Habit. D. Ligule. E. Panicle branch with spikelet pair, lower spikelet staminate or sterile, upper spikelet bisexual (perfect). Peterson et al., Muhlenbergiinae from northeastern Mexico 945 Reyna & R.H. Cardenas (US), P.M. Peterson 18805 &J. Valdes-Reyna (US); Canon San Lorenzo, Sierra de Zapaliname, 8 km S of Saltillo & 3.2 km E de Buenavista, R. Lopez Aguillon s.n. (ANSM); 3 mi SE of Saltillo, LM. Johnston 7250 (US); road to Canyon San Lorenzo, P.M. Peterson 10545 & C.R. Annable (US); Las Vigas, Canon de la Carbonera, Sierra de Arteaga, J. Valdes-Reyna 1797, J.A. Villarreal Q. cV M.A. Carranza P. (ANSM); Predio El Cristal, E. Perez Torres 61 (COCA): Municipio de Castafios, Paso de San Lazaro, Sierra de la Gavia, 37.6 mi S de Monclova on Hwy 57, P.M. Peterson 9990, C.P. Annable &>J. Valdes-Reyna (ANSM, US); Municipio de Cuatrocienegas, Sierra de la Madera, Canon Charreteras, Rancho Charreteras, J.A. Villarreal Q. 7350, M.A. Carranza P. & R. Rodriguez L. (ANSM); Canada Los Pozos. 8 mi SW of Tanque El Tropical along road to Canon del Desiderio, T.L. Wendt s.n. &>}. Valdes-Reyna (MEXU); Municipio de Muzquiz, near Santo Domingo, F.W. Lyle 454, CM. Mailer (ANSM, US); Sierra Maderas del Carmen, E. Garcia Aguilera s.n. (ANSM); Municipio de Ocampo, Mesa Grande, 40 km NW of Hacienda de LaEncantada, P.M. Stewart 1631 (MEXU); Wbase of Picacho del Fuste, NE of Tanque Vaionetta, I. M. Johnston 8444 (MEXU); Municipio de Parras, Sierra de Parras, 2-4 km S of Ejido Colorado, 8.8 km al W of Parras, C.P. Cowan 3610 (TEX-LL); Municipio de Ramos Arizpe, Sierra de la Paila, Ejido El Cedral, J.A. Villarreal Q. 5330, M.A. Carranza P. & A. Rodriguez G. (ANSM); Municipio de Saltillo, 20 km E of Saltillo, Carretera Saltillo-Torreon, R. Almeida 1642 (ANSM); 4 km W of Saltillo, Carretera Saltillo-General Cepeda, J. Valdes-Reyna 1553, L.E. Rodriguez G. & R. Vdsquez A. (ANSM); 6 mi W of Saltillo along highway 40 towards Torreon, S.L. Hatch 5040 &J. Valdes-Reyna (ANSM); Buenavista, Brigada Coahuila 102, 103, 104 (COCA); Buenavista, 7 km S de Saltillo, Carretera 54 Saltillo-Concepcion del Oro, A. Rodriguez-Guillen 101, R.E. Rodriguez-Char ua 107, M. Jimenez-E. s.n., N. Ochoa- R. s.n., R. Palomo-Garza & P. Garcia-Solis s.n. (ANSM); Canon San Lorenzo, 1.5 km E of Pozo, R. Lopez Aguillon s.n. (ANSM); Cerro del Pueblo, W of La Ciudad de Saltillo, J. Valdes-Reyna 2045, M. Martinez M. & M.A. Carranza P. (ANSM); Hwy 54 towards Concepcion del Oro, 6 km S of Saltillo, M.E. Barkworth 5108, P.S. HogeJ. Valdes-Reyna, cv M.A. Carranza P. (ANSM); Rancho Experimental Los Angeles. 48 km S of Saltillo, Carretera 54 Saltillo-Concepcion del Oro, J.A. Villarreal Q. 6710, S.L. Hatch 4538, C.W. MordenJ. Valdes-Reyna, M.A. Carranza P. & D.E. Lozano (ANSM); Saltillo, G. Eisher s.n. (UAT); Sierra Madre Oriental, Terrenos de Tranquitas, R.M. Francois 5827 & J. Passini (ANSM); Sierras adyacentes al Paso de Carneros, J.S. Marroquin-de la Fuente 3058 (ANSM); 29 km S of Saltillo on MEX 54 just W of Estacion Caranaros, P.M. Peterson 8413 & M.A. Carranza P. (US); Municipio de San Pedro, entre Cuatrocienegas & San Pedro, A. Rodriguez-Gdmez945,J.J. Lopez&J. L. ElizondoF. (ANSM, TEX); Municipio de Sierra Mojada, Canon de Tinaja Blanca, W of Santa Elena Mines, R.M. Stewart 1950 (US); Municipio de Torreon, Sierra dejimulco, 11.7 kmE of Flor dejimulco, P.M. Peterson 8453,J. Valdes-Reyna, PA. Fryxell &J.A. Villarreal Q. (ANSM, US); Sierra dejimulco, Mina San Jose, J.A. Villarreal Q. 7791 & M.A. Carranza P. (ANSM, TEX). Nuevo Leon: 12.3 mi S of Milagro, P.M. Peterson 17810, J. Valdes-Reyna & G.S. Hinton (US); 16 km NE of Sandia on road to La Ascension. P.M. Peterson 15826 &J. Valdes-Reyna (US); 5.2 miS of Zaragoza on road towards Ejido LaEncantada, P.M. Peterson 16733, J. Valdes-Reyna &M. Sosa Morales (US); 9.4 mi W of San Antonia de Pena Nevada, P.M. Peterson 16791, J. Valdes-Reyna & M. Sosa Morales (US); 75.8 km N of Dr. Arroyo on Hwy 61, P.M. Peterson 11144 & C.R. Annable (US); 6.5 mi S of Border of Coahuila and Nuevo Leon on Hwy 57 towards Matehuala, P.M. Peterson 13286 &M.B. Knowles (US); 2 mi Wof Dieciocho de Marzoup road towards Cerro Potosi, P.M. Peterson 13325 & M.B. Knowles (US); 36 mi NE of Dr. Arroyo on Hwy 61 towards Linares, P.M. Peterson 13366 &M.B. Knowles (US); Municipio de Galeana, lOmiE of San Roberto along highway 58, S.L. Hatch 4978, J. Valdes-Reyna &P. DdvilaA. (ANSM); 12 km SE of San Roberto on highway 58, S.L. Hatch 4580, C.W. Morden &J. Valdes-Reyna (ANSM); Alrededor de Galeana, J.A. Ochoa-Guillemar 1258 (COCA); Hacienda Pablillo, M. Taylor-Edwards 134 (MEXU); Rancho Aguililla, G.B. Hinton 19863 (MEXU, TEX); alrededores del poblado Santa Clara de Gonzalez, N. Bazaldua-Bazaldua 110 (COCA). Tamaulipas: Municipio de Bustamante, Camino a La Joya de San Francisco, J.L. Ramos-Delgado 99 (COCA); Municipio deMiquihuana, 15 kmSWof Miquihuana, P. Hiriart301, V.Judrez&R. Molczadzhi (MEXU); 7km Wof Miquihuana, P. Hiriart 899,V Judrez, R- MolczadzkiJ.L. Lopez, F. Ojeda&J.A. Gutierrez (MEXU); 9 km N of Miquihuana, P. Hiriart335, VJudrez&R. Molczadzki (MEXU); 3 mi N of Miquihuana, Stanford 2481, Lauber & Taylor (US); Colonia La Pena, J.F. Iribe-Duarte 106 (COCA); Ejido El Aserradero, J.G. Galvdn-lnfante 37 & R.A. Carranco-Rendon 70 (COCA); Ejido Valle Hermoso, Canon de La Sierra Miquihuana, R.A. Carranco-Rendon (COCA); Municipio de Palmillas, Ejido Palmillas, R.A. Carranco-Rendon 213 (COCA); Municipio de Tula, La Tapona, M.H. Cervera-Rosado 133 (COCA). 4. Lycurus setosus (Nutt.) C. Reeder, Phytologia 57:287. 1985. (Fig. 3, C-E). Pleopogonsetosum Nutt., Proc. Acad. Nat. Sci. Philadelphia 4:25. 1848. TYPE: U.S.A. NEW MEXICO: Santa Fe Co.: mountains near Santa Fe, 1841 or 1842, William Gambel s.n. (HOLOTYPE: K!; ISOTYPES: PH, US-610839 fragm. ex KJ). Lycurus alopecuroides Griseb., Abh. Konigl. Ges. Wiss. Gottingen 19: 255-256. 1874. TYPE: ARGENTINA: PROV. CATAMARCA: ca. Belen, en el altivalle de las Granadillas, Feb 1872, P G. Lorentz 548 (HOLOTYPE: GOET; ISOTYPES: BA!, BAA!, CORD, SI!, US-996080 fragm. ex GOET!). Lycurus phleoides var. glaucifolius~Beal, Grass. N. Amer. 2:271. 1896. TYPE: MEXICO. CHIHUAHUA: rocky hills near Chihuahua, 28 May 1885, C.G. Pringle 426 (LECTOTYPE: MSC designated by Hitchcock, Contr. U.S. Natl. Herb. 17:305. 1913, without explicitly citing a specific sheet in a specific herbarium, fully lectotypified by C. Reeder, Phytologia 57:287. 1985, who cited the MSC specimen as "holotype": isolectotypes: MO-3701765!, NY, P!, SI!, US-996079!). Caespitose perennials. Culms 30-60 cm tall, erect, scabrous to puberulent just above or below the nodes. Leaf sheaths usually 1-5 cm long, glabrous to pubescent, compressed-keeled near base; ligules (2-)3-12 mm long, acuminate to erose, sometimes with lateral lobes the same length as the ligule, the lateral lobes decurrent below; blades 4-10(-2) cm long, 1-2.5 mm wide, flat or folded, glabrous to puberulent below 946 Journal of the Botanical Research Institute of Texas 1(2) and puberulent to hispidulous above, margins and midvein whitish-thickened, apex acuminate with slender awn-like seta 3-8(-10) mm long on the upper blades. Panicles (2-)4-10 cm long, 4-8 mm wide, contracted, narrow, densely flowered, and spikelike; primary branches 0.1-0.3 cm long, tightly appressed. Spikelets3-4 mm long, 1-flowered; glumes 1-2 mm long, scaberulous near apex, awned, the awns 1-5 mm long; lower glumes usually 2(3-)-nerved; upper glumes 1-nerved, awns 2-5 mm long; lemmas 3-4 mm long, puberulent along the margins, awned, the awns 1-3 mm long; paleas 3-4 mm long, puberulent between the nerves; anthers 1.5-2 mm long, yellow. Caryopses 1.8-2.2 mm long, brownish. In = 40. Phenology.?Flowering July through October. Distribution and habitat.?Wooded canyons, rocky slopes, desert grasslands, and rock outcrops with Pinus spp. Quereus spp., Boutdoua hirsuta, Chrysothamnus spp., Pseudostuga menziesii, Cupressus spp., Abies spp., Cornus stolonifera, Ceanothus spp., and Yueea spp.; northwestern Mexico in Baja California, Chihuahua, Durango, Sonora, and extending into the southwestern U.S.A., then disjunct in northwestern Argentina and Bolivia (Espejo Serna et al. 2000; Peterson et al. 2001b; Reeder 1985; Sanchez & Rugolo de Agrasar 1986); 1400-2500 m. Specimens examined. MEXICO. Coahuila: Sierra El Pino, 39.5 km W of Rancho El Cimarron, P.M. Peterson 10672 & C.R. Annable (US); Municipio de Acuna, Serranias del Burro, Rancho El Bonito, Canon El Bonito, 7 mi W de la casa principal, D.H. Rishind 2185 (ANSM); Municipio de Cuatrocienegas, Sierra de la Madera, Canada Los Posos, 0.8 mi by road SW from Tanque El Tropical along road to Canon del Desiderio, ]. Valdes-Reyna 1053 & T.L. Wendt (ANSM); Sierra de la Madera, Canon del Agua, mouth of canyon, ]. Valdes-Reyna 1000, 1012 & T.L. Wendt (ANSM); Sierra Madre Orientale, Ejido el Cinco, R.M. Francois 5792 &]. Passim (ANSM); Municipio de General Cepeda, Sierra Madre Oriental Ejido El Cinco, R.M. Francois 5783 cvj. Passini (ANSM); Municipio de Muzquiz, Cuesta de la Encantada, J.A. Santos- L. s.n. (ANSM); Sierra del Carmen, R.M. Francois 5514 &]. Passini (ANSM); Ejido San Francisco, P.M. Peterson 18842,]. Valdes-Reyna & C. Sifuentes (US); Madera del Carmen, 7.2 mi NW of Pilares, P.M. Peterson 18876 &]. Valdes-Reyna (US); Campo El Dos, P.M. Peterson 18910 cyj. Valdes-Reyna (US); Municipio de Sierra Mojada, San Antonio de los Alamos, I.M.Johnston 8252a (US). Muhlenbergia Schreb., Gen. PI. (ed.8) 1:44. 1789. TYPE: Muhlenbergia schreberi}^. Gmel., (LECIOTYPE: designated by Nash in Britton & Brown, 111. Fl. N. U.S., ed. 2, 1:184. 1913). Plants annual or perennial; hermaphrodites or occasionally monoecious; often caespitose, sometimes mat- forming, usually rhizomatous, rarely stoloniferous. Culms 2-300 cm tall, erect, geniculate, or decumbent, usually herbaceous, sometimes becoming woody; internodes solid or hollow. Leaf sheaths open, auricles absent; ligules membranous or hyaline, sometimes firm or coriaceous, acuminate to truncate, sometimes minutely ciliolate, sometimes with lateral lobes longer than the central portion; blades narrow, flat, folded, or involute, sometimes arcuate. Inflorescences terminal, sometimes also axillary, open to contracted or spikelike panicles; disarticulation usually above the glumes, occasionally below the pedicels. Spikelets 1(2-3)- flowered, laterally compressed or terete; glumes subequal in length, mostly shorter than the lemmas, or as long or exceeding the lemmas, usually (0)1(2, 3)-nerved, apices entire, erose, or toothed, truncate to acuminate, sometimes mucronate or awned; lower glumes sometimes rudimentary or absent, occasionally bifid; upper glumes shorter than to longer than the florets; lemmas membranous or rather firm, glabrous, scabrous, or with short hairs, 3-nerved (occasionally appearing 5-nerved), callus glabrous or hairy, apices awned, mucronate, or unawned; awns, if present, straight, flexuous, sinuous, or curled, sometimes borne between 2 minute teeth; paleas membranous or rather firm, well developed, about as long as the or shorter than the lemma, 2-nerved, rounded on the back; lodicules 2, short, fleshy, truncate; lateral margins thin; ovary glabrous, styles free to their bases, stigmas 2; stamens (1, 2)3, anthers purple, orange, yellow, or oli- vaceous. Caryopses elongate, fusiform or elliptic, slightly dorsally compressed, usually not falling free from the lemma and palea. Cleistogamous panicles sometimes present in the axils of the lower cauline leaves, enclosed by a tightly rolled, somewhat indurate sheath. Embryo large, with an epiblast, scutellar tail, and elongated mesocotyl; embryonic leaf margins meeting, endosperm hard. Chromosome number x = 10. Etymology.?Named for Gotthilf Henry Ernest Muhlenberg (1753-1815), a Lutheran minister and pioneer botanist of Pennsylvania. Comments.?A good historical account, biogeographical summary, and subgeneric classification of Muhlenbergia was given in Peterson (2000) and Peterson and Herrera Arrieta (2001). Based on population Peterson et al., Muhlenbergiinae from northeastern Mexico 947 genetic studies of the amphitropical disjunct, Muhlenbergia torreyii (Peterson & Ortiz-Diaz 1998), it is clear that migration predominantly occurred from a center of diversity (for Muhlenbergia & Muhlenbergiinae) in southwestern North America (centered in northern Mexico) to northern Argentina-southwestern Bolivia (Peterson &r Herrera Arrieta 1995; Peterson &r Columbus 1997; Sykes et. al. 1997; Peterson & Morrone 1997; Peterson &r Ortiz-Diaz 1998; Peterson 2000). Chihuahua apparently has the highest number of species of Muhlenbergia (59 spp.), followed by Durango with 55 species (Herrera Arrieta 2001; Herrera Arrieta & Peterson 2007). In northeastern Mexico, M. jaime-hintonii is endemic to the region and is known only from Nuevo Leon. Even though preliminary phylogenetic results of trnL-F and ITS DNA sequences indicate that Muhlen- bergia is polyphyletic, there are monophyletic lineages that correspond to previous delineated taxa (Peterson et al. 2001a, 2004; Columbus & Peterson, in prep.). In addition to all species of Aegopogon and Pereilema, the following seven species placed in Muhlenbergia subg. Muhlenbergia are well supported in the molecular analysis and exhibit PCK-like anatomical characteristics: M. glauca, M. microsperma, M. polycaulis, M. ported, M. racemosa, M. spicijormis, and M. tenuifolia. Muhlenbergia distichophylla, M. dubia, M. emersleyi, M. gypsophila, M. jaime-hintonii, M. lindheimeri, M. macroura, M. pubigluma, M. purpusii, M. rigens, M. rigida, M. robusta, M. setifolia, and M. strieta (Muhlenbergia subg. Trichochloa) have anatomical characters of deep adaxial furrows, vascular bundles positioned in two or three levels, and inflated cells located below (abaxial to) the primary vascular bundles; and are found in a well supported molecular clade (Peterson et al. 2001a, 2004; Peterson &r Herrera Arrieta 2001). There is good molecular support for M. montana, M. quadridentata, and M. vire- scens, all members of a group referred to as the "Muhlenbergia montana complex" that have 3-nerved upper glumes and sclerosed phloem (Peterson et al. 2001a, 2004; Peterson &C Herrera Arrieta 2001). The annuals, M. depauperata, M.fragilis, and M. minutissima, with M. arenicola and M. torreyii form a fairly well supported molecular clade; and Muhlenbergia arenaeea, M. asperijolia, M. repens, M. utilis, M. villiflora, and M. wrightii are all members of a fairly well supported molecular clade that includes the M. montana complex, Lyeurus- Schaffnerella, Chaboissaea spp., and Schedonnardus paniculatus (Columbus & Peterson, in prep). 5. Muhlenbergia arenaeea (Buckley) Hitchc, Proc. Biol. Soc. Wash. 41:161. 1928. (Fig. 1, C-G). Spombolus arenaceus Buckley, Proc. Acad. Nat. Sci. Philadelphia 14:89. 1862. TYPE: U.S.A. NEW MEXICO/TEXAS: May-Oct 1849, C.H. Wright 737 (LECTOTYPE: GH designated by Hitchcock, Man. Grass. U.S. 886. 1935, but without citing a specific sheet in a specific herbarium; ISOLECTOTYPE: US-997371!)- Spombolus auriculatus Vasey Contr. U.S. Natl. Herb. 3(1):64. 1892. TYPE: U.S.A. TEXAS: Duval Co.: Pena, 1890, C.C. Neattey 492 (LECTOTYPE: US-997369! designated by Hitchcock, N. Amer. Fl. 17(6):447. 1935, but without citing a specific sheet in a specific herbarium). Rhizomatous perennials. Culms 10-30(-40) cm tall, decumbent, terete to somewhat compressed-keeled near the base; internodes scaberulous below the nodes. Leaf sheaths about V2 as long as the internodes, margins hyaline; ligules 0.5-2 mm long, hyaline, with lateral lobes or auricles 1-2 mm long; blades 0.7-4(-6) cm long, 0.5-1.7 mm wide, flat, occasionally folded, tapering, scabrous abaxially, strigulose adaxially, margins and midveins thickened, whitish, apices narrow, often sharp, erose. Panicles 5-15 cm long, 4-14 cm wide, broadly ovoid, open; primary branches 2-8 cm long, capillary, straight to slightly flexuous, diverging 45-80(-100)? from the rachises, never appearing fascicled, naked proximally; pedicels 1-11 mm long, usually longer than the spikelets. Spikelets 1.5-2.5 mm long, occasionally with 2 florets; glumes 0.9-2 mm long, equal, 1-nerved, usually acute to acuminate, occasionally erose and mucronate, mucros to 0.2 mm long; lemmas 1.5-2.5 mm long, lanceolate to oblong-elliptic, plumbeous to purplish, sparsely appressed-pubescent on the lower V2 of the margins and midveins, hairs to 0.3 mm long, apices acute to obtuse, sometimes shallowly bilobed, mucronate, mucros to 0.3 mm long; paleas 1.5-2.6 mm long, lanceolate, glabrous, obtuse to acute; anthers 1-1.5 mm long, yellowish to purplish. Caryopses 1-1.3 mm long, elliptic, brownish. Distribution and habitat.?Muhlenbergia arenaeea grows in sandy flats, plains, alluvial fans, washes, depressions, and alkaline mesas in open grasslands, at elevations of 1000-2200 m. It ranges from the southwestern U.S.A. to northern Mexico in Chihuahua, San Luis Potosi, and Zacatecas (Espejo Serna et al. 2000; Peterson 2003). 948 Journal of the Botanical Research Institute of Texas 1(2) Specimens examined. MEXICO. Coahuila: 153.2 km NW of Muzquiz on Hwy 53 towards Boquilla del Carmen, P.M. Peterson 10602 & C.R. Annable (US); Sierra El Pino, 9.2 km SW of Rancho El Cimarron, P.M. Peterson 10624 & C.R. Annable (US); Municipio de Acuiia, Sierra del Carmen, E.G. Marshjr. 907 (MEXU); Municipio de Ocampo, Rancho el Barranquito, 50 Km de Ocampo rumbo a Sierra Mojada, M.A. Carranza P. 576 & F.J. Carranza P. (ANSM); Rancho La Rueda, 87 km NW of Ocampo, D. Ibarra s.n. (ANSM); Municipio de Saltillo, 12 km N of the Coahuila?Zacatecas state line along highway 54 between Saltillo and Concepcion del Oro, Zacatecas, S.L. Hatch 4516. C. W. Morden &J. Valdes-Reyna (ANSM); 29.2 mi S of Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, P.M. Peterson 10033. C.R. Annable &]. Valdes-Reyna (ANSM, US); 3 mi E of San Jose, l.M. Johnston 8217 (MEXU); Municipio de Sierra Mojada, Reserva de la Biosfera de Mapimi limite del estado de Coahuila, Chihuahua & Durango, R. Ruiz Esparza R. 552 (ANSM). 6. Muhlenbergia arcnicola Buckley, Proc. Acad. Nat. Sci. Philadelphia 14:91. 1862. (Fig. 4, A-E). Podose- mum arenicola (Buckley) Bush, Amer. Midi. Naturalist 7(2):40. 1921. TYPE: U.S.A. TEXAS: arid places in western Texas, C. Wright 735 (LECTOTYPE: PH designated by Hitchcock, Man. Grass. U.S. 886 (1935), but without citing a specific sheet in a specific herbarium; ISOLECTOTYPE: US-87239 fragm!). Caespitose perennials. Culms (15?)20?60(?70) cm tall, somewhat decumbent, 1 or more nodes exposed; internodes hispidulous below the nodes. Leaves somewhat basally concentrated, most blades not reaching more than Vi-Vi of the plant height; leaf sheaths usually a little shorter than the internodes, not keeled, scaberulous, margins hyaline, basal sheaths rounded, not becoming spirally coiled when old; ligules 2-9 mm long, hyaline, acute, lacerate, often with lateral lobes; blades 4-10(-16) cm long, 1-2.2 mm wide, not arcuate, flat, folded, or involute, scabrous, often glaucous, midveins and margins not thickened, green. Panicles 12-30 cm long, 5-20 cm wide, diffuse; primary branches 1-10 cm long, diverging 30-80? from the rachises, naked basally; pedicels 1?4(?6) mm long, erect. Spikelets 2.5-4.2 mm long; glumes 1.4-2.5 mm long, equal, 1-nerved, apices scaberulous, acute to acuminate, minutely erose, sometimes mucronate, the mucro to 1 mm long; lemmas 2.5-4.2 mm long, narrowly elliptic, usually purplish, scabrous distally, appressed-pubescent on the lower Vz-3A of the margins and midveins, apices acuminate, awned, awns 0.5-4 mm long; paleas 2.5-3.5 mm, narrowly elliptic, intercostal region sparsely pubescent, apices acuminate, with 2 short mucros 0.1-0.2 mm long; anthers 1.5-2.1 mm, greenish. Caryopses 1.9-2.3 mm long, fusiform, brownish. In = 80, 82. Distribution and habitat.?Muhlenbergia arenicola grows on sandy mesas, limestone benches, and in val- leys and open desert grasslands, associated with Bouteloua gracilis, B. uniflora, Larrea tridentata, and Yucca carnerosana at elevations of 600-2135 m. The range of M. arenicola extends to southwestern U.S.A. and the species is a disjunct in northwestern Argentina (Peterson & Ortiz-Diaz 1998). Specimens examined. MEXICO. Coahuila: Sierra El Pino, 9.2 km SW of Rancho El Cimarron; P.M. Peterson 10619 &> C.R. Annable (US); 153.2 km NW of Muzquiz on Hwy 53 towards Boquilla del Carmen, P.M. Peterson 10603 & C.R. Annable (US); 0.3 km E of Hwy to Zacatecas up road to Canyon San Lorenzo, P.M. Peterson 10550, C.R. Annable cvj, Valdes-Reyna (US); Municipio de Acuha, 2 km N of El Conejo on the winding road to La Huerfanita, M.C. Johnston 9192. F. Chiang C. & J.L. Wendt (ANSM); Municipio de Arteaga, Sierra de Arteaga, Bosque de la Montana, 10 km del entronque Los Lirios & carretera 57 a Matehuala, rumbo a los Lirios, P.S. Hoge. 257, M.E. Barkworth, J.A. Vitlarreal Q. CstJ. Valdes-Reyna (ANSM); Municipio de Francisco I. Madero, Valle de Buenavista, S de los Remedios, T.L. Wendt 1387 cy E.J. Lott (ANSM); Municipio de Muzquiz, La Cuesta del Plomo on the Muzquiz?Boquillas highway, F. Chiang-Cabrera 9207 (MEXU), T.L. Wendt & M.C. Johnston 9207 (ANSM); Municipio de Ocampo, Rancho experimental Santa Teresa de La Rueda, 87 km NE of Ocampo, brecha Ocampo?Boquillas del Carmen, R. Vdsquez-Aldape s.n. (ANSM); Rancho experimental Santa Teresa de La Rueda, 87 km NE of Ocampo, brecha Ocampo?Boquillas del Carmen, M. Vdsquez-Rodriguez s.n. (ANSM); Rancho La Rueda, 87 km NE of Ocampo, D. Ibarra s.n. (ANSM); Municipio de Parras, Rancho el Tunal, 25 km ESE of Parras de la Fuente, A. Rodriguez-Gdmez 1181 & M.A. CarranzaP. (ANSM); Municipio de Saltillo, 28.3 mi S of Saltillo, carretera 54 a Concepcion del Oro, Zacatecas, P.M. Peterson 10026, C.R. Annable &J. Valdes-Reyna (ANSM, US); 47 km S of Saltillo on MEX Hwy 54 to Concepcion del Oro near entrance road to El Salitre Randiera, P.M. Peterson 10032, C.R. Annable &]. Valdes-Reyna (ANSM, US); 29.2 mi S of Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, P.M. Peterson.10032, C.R. Annable &]. Valdes-Reyna (ANSM, US); 30.6 km SE of Saltillo on Hwy 57 towards San Luis Potosi, P.M. Peterson 6239 cy C.R. Annable (US); 50 km S of Saltillo, carretera 54 a Concepcion del Oro, Zacatecas, entronque El Colorado, J.A. Villarreal Q. 2061, M.A. CarranzaP. &]. Valdes-Reyna (ANSM, MEXU); 3 mi E of San Jose, l.M. Johnston 8219 (MEXU); Entronque Derramadero, a 20 km S de Saltillo por la carretera Saltillo-Zacatecas, carretera 54, J. Valdes-Reyna cy M.A. Carranza P. (ANSM); Rancho experimental Los Angeles, 48 km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, J. Espinosa-Aburtor 56, S. L. Hatch. 5019, G.A. Puente-Tristdn.J. S. Sierra-Tristan cyj. Valdes-Reyna (ANSM); Municipio de Sierra Mojada, 10-15 km E of San Antonio de los Alamos, I.M.Johnston 8288 (MEXU). Nuevo Leon: 64.4 km S of San Rafael on Hwy 57, P.M. Peterson 6236 & C.R. Annable (US); 12.3 mi S of Milagro, P.M. Peterson 17815, J. Valdes-Reyna cy G.S. Hinton (US); .Municipio de Galeana, 2 km SE of El Canelito, on road to San Peterson et al., Muhlenbergiinae from northeastern Mexico 949 FIG. 4. Muhlenbergia arenicola [P.M. Peterson 6239 & CM. Annable (US)]. A. Habit B. Ligule. C. Glumes. D. Floret. E. Lodicules, stamens, and pistil. Muhlen- bergia torreyi [P.M. Peterson 5608 & C.R. Annable (US)]. F. Habit. G. Ligule. H. Glumes. I. Lemma. 950 Journal of the Botanical Research Institute of Texas 1(2) Juan de Dios, M.C.Johnston 7984, T.L. Wendt (ANSM); Ejido El Tokio, M.L. Avalos-Marin s.n. (UAT, ANSM). Tamaulipas: Municipio de Bustamante, Ejido Felipe Angeles 2 km NO rumbo a Bustamante, R. Diaz-Perez s.n. (UAT). 7. Muhlenbergia asperifolia (Nees & Meyen ex Trin.) Parodi, Revista Fac. Agron. Veterin. (Buenos Aires) 6:117. 1928. (Fig. 5, A?D). Vilfa asperifolia Nees & Meyen ex Trin., Mem. Acad. Imp. Sci. Saint-Petersbourg, Ser. 6, Sci. Math., Seconde Pt. Sci. Nat. 6,4(l-2):95. 1840. Sporoholus asperijolius (Nees & Meyen ex Trin.) Nees & Meyen, Gramineae 9-10. 1841. TYPE: Chile. Rio Mayno, 1000' alt, Mar 1831, Meyen s.n. (SYNTYPES: B, BAA-3464 fragm. ex Bl, LE-TRlN-1679.01bQ; Copiapo, Meyen s.n. (SYNTYPE: LE-TRIN-1679.01a!). Agrostis eremophila Speg., Anales Mus. Nac. Hist. Nat. Buenos Aires 7:190. 1902. Agrostis distichophylla Phil., Fl. Atacam. 54. 1860. norm illeg. horn. TYPE: Chile, prope Tilopozo ad marginem paludos, 23.20 lat., 7000 It (isotypes: BAA-4153 Iragm. ex SCO!, SGO-63100, SGO-37135, US-1939353 Iragm. ex SGO-37135!). Rhizomatous perennials, occasionally stoloniferous. Culms 10-60(-100) cm tall, decumbent-ascending, bases somewhat compressed-keeled; internodes glabrous, shiny below the nodes. Leaf sheaths glabrous, margins hyaline; ligules 0.2-1 mm long, firm, truncate, ciliate, without lateral lobes; blades 2?7(?11) cm long, 1-2.8(-4) mm wide, flat, occasionally conduplicate, smooth or scaberulous abaxially, scaberulous adaxially, margins and midveins not conspicuously thickened, greenish, apices acute, not sharp. Panicles 6-21 cm long, 4-16 cm wide, broadly ovoid, open; primary branches 3-12 cm, capillary, lower branches spreading 30-90? from the rachises, never appearing fascicled; pedicels 3-14 mm long, longer than the spikelets. Spikelets 1.2-2.1 mm long, occasionally with 2 or 3 florets; glumes 0.6-1.7 mm long, equal, pur- plish, scaberulous, particularly on the veins, 1-nerved, apices acute; lemmas 1.2-2.1 mm long, lanceolate to oblong-elliptic, somewhat plumbeous, glabrous, usually smooth, occasionally scaberulous near the apices, apices acute, unawned or mucronate, mucros to 0.3 mm long; paleas 1.2-2.1 mm long, lanceolate, glabrous, acute; anthers 1?1.3 mm long, greenish-yellow to purplish at maturity. Caryopses 0.8-1 mm long, fusiform, brownish. In = 20, 22, 28. Distribution and habitat.?Muhlenbergia asperifolia grows in moist, often alkaline meadows, beach margins, and sandy washes, on grassy slopes, and around seeps and hot springs, at elevations of 55-3000 m. This species is common in western U.S.A. and Canada (Peterson 2003), and is also found in Argentina, Bolivia, and Chile (Zuloaga et al. 1994). In Mexico M. asperifolia occurs in Baja California, Chihuahua, Durango, Jalisco, and San Luis Potosi (Espejo Serna et al. 2000). Comments.?The caryopses of Muhlenbergia asperifolia are frequently infected by a smut, Tilletia asperifolia Ellis & Everhart, which produces a globose body filled with blackish-brown spores. Specimen examined. MEXICO. Coahuila: Municipio de Cuatrocienegas, Dunas cercanas a la Poza de la Becerra en Cuatrocienegas, J.A. Villarreal Q. 3200, J. Valdes-Reyna & M.A. Carranza P. (ANSM). 8. Muhlenbergia depauperata Scribn., Bot. Gaz. 9:187, f. 1-2. 1884. (Fig. 6, A-C). TYPE: U.S.A. ARIZONA: Coctrise Co. or Santa Cruz Co.: Mustang Mountains, 13 Sep 1884, Piingle s.n. (LECTOTYPE: US-994221! designated by McVaugh, Fl. Novo- Galiciana 14:236. 1983, but without indicating a specilic sheet, specific sheet indicated by Peterson & Annable, Syst. Bot. Monogr. 31:35. 1991; ISOLECTOTYPES: Kl, MO!, MSC!, NY!, PI, US!, VT!, W-1916-27671!). Muhlenhergiaschaffneii'E. Fourn., Mexic. PI. 2:85. 1886. TYPE: MEXICO. Tacubaya, W Schaffner s.n. (LECTOTYPE: P! designated by Hitchcock, Contr. U.S. Natl. Herb. 17:294. 1913; ISOLECTOTYPES: LE (2 sheets)!, MO!, PI, US-3412353!, US-2312354 fragm. ex PI). Caespitose annuals. Culms 3-15 cm tall; internodes mostly scaberulous or pubescent, pubescent or strigose below the nodes, much branched at the lower nodes. Leaf sheaths often longer than the internodes, some- what inflated, smooth or scabrous, keeled, margins scarious; ligules 1.4-2.5 mm long, membranous, acute, with lateral lobes; blades 1-3 cm long, 0.6-1.5 mm wide, flat or involute, scabrous to strigose, midveins and margins thickened, whitish. Panicles 2.5-8.5 cm long, 0.5-0.7 cm wide, contracted; primary branches 1-2.2 cm long, appressed, spikelet-bearing to the base, spikelets borne in subsessile-pedicellate pairs; lon- ger pedicels 3-6 mm long, scabrous; disarticulation beneath the spikelet pairs at base of pedicel. Spikelets 2.5-4.5 mm long, appressed; glumes 2.3-5.1 mm long, equaling or exceeding the florets; lower glumes 2.3-4 mm long, subulate, 2-nerved, minutely to deeply bifid, teeth aristate or with awns to 1.3 mm long; upper glumes 3-5.1 mm long, lanceolate, 1-nerved, entire, acuminate; lemmas 2.5-4.5 mm long, narrowly Peterson et al., Muhlenbergiinae from northeastern Mexico 951 1mm FIG. 5. Muhlenbergia asperifolia [P.M. Peterson 1703, C.R. Annable, R.F. Thome &K. Kubitskie (US)]. A. Habit. B. Ligule. C. Glumes. D. Lemma. Muhlenbergia tenuifolia [P.M. Peterson 9705 & A. Campos-Villanueva (US, ANSM)]. E. Habit. F. Ligule. 6. Glumes. H. Floret. 952 Journal of the Botanical Research Institute of Texas 1(2) fK.6.Muhlenbergiadepauperata[PM Peterson 4082 & C.R. Annable W\l, ENCB, GH, MEXU, MICH, MO, NMC, NY, RSAJAES, UC, UNLV, UK, US, WIS, WS)]. A. Habit. B. Glumes. C. Florets. Muhlenbergia fragilis [P.M. Peterson 5456 & C.R. Annable (US)]. D. Habit. E. Ligule. F. Glumes. G. Lemma. Muhlenbergia minutissima [P.M. Peterson 5601 & C.R. Annable (US)]. H. Habit. I. Ligule. J. Spikelet. K. Floret. Peterson et al., Muhlenbergiinae from northeastern Mexico 953 lanceolate, light greenish-brown to purplish, scabrous, appressed-pubescent on the margins and midveins, apex acuminate, awned, the awns 6-15 mm long, stiff; paleas 2.4-3.6 mm long, lanceolate, intercostal region appressed-pubescent, apex acuminate; anthers 0.5-0.8 mm long, purplish to yellowish. Caryopses 1.5-2.3 mm long, narrowly fusiform, brownish. 2n = 20. Distribution and habitat.?Muhlenbergia depauperata grows in gravelly flats, rock outcrops, exposed bedrock, and sandy banks, in grama grassland associations, usually on soils derived from calcareous parent materials, associated with species of Selaginella, Hechtia, Opuntia, Salvia, Brahea, and Juniperus; 1530-2400 m. The range of M. depauperata extends into the southwestern U.S.A., and in Mexico this species occurs in Chihuahua, Durango, Aguascalientes, Mexico, Distrito Federal, Guanajuato, Jalisco, San Luis Potosi, Puebla, Veracruz, and Oaxaca (Espejo Serna et al. 2000). Comments.?Muhlenbergia depauperata and M. brevis CO. Goodd., found commonly in the Sierra Madre Occidental, share several features with Lycurus: spikelets borne in pairs, 2-nerved and 2-awned lower glumes, 1-nerved and awned upper glumes, acuminate, awned lemmas with short pubescence along the margins, and pubescent paleas. Specimens examined. MEXICO. Coahuila: Municipio de Ocampo, W side of Potrero de la Mula, 20 km NW of Ocampo, l.M. Johnston 9250 (MEXU); Municipio de Saltillo, Sierra Madre Oriental, 18 mi S of Saltillo on Mexico 54 and 1.3 mi W on road to microondas, just W of Estacion Carneros, P.M. Peterson 8425 & M.A. Carranza P. (ANSM, MEXU, US); Municipio de Torreon, Sierra de Jimulco, 3 km N of Mina San Jose and 8 km NE of Estacion Otto, M.C. Johnston 9552, F. Chiang C.& I.L. Wendt (ANSM). Nuevo Leon: 6.5 mi S of border of Coahuila and Nuevo Leon on Hwy 57 towards Matehuala, P.M. Peterson 13282 cV M.S. Knowles (US); 5.2 mi S of Zaragoza on road towards Ejido La Encantada, P.M. Peterson 16741,}. Valdes-Reyna cv M. Sosa Morales (US); Municipio de Santiago, La Escondida, 1. Cahral-Cordero 598 (ANSM). 9. Muhlenbergia distichophylla (J. Presl) Kunth, Enum. PI. 1:202. 1833. (Fig. 7, A-C). Podosemumdistichophyllum J. Presl, Reliq. Haenk. 1(4-5):231. 1830. Epicampes stricta var. distichophylla (J. Presl) M.E. Jones, Contr. W. Bot. 14:6. 1912. TYPE: MEXICO: T. Haenke 173 (HOLOTYPE: PR, photo US!; ISOTYPES: MO-1837831!, US-90711 fragm. ex PR!, US fragm. ex W!, Wl). Muhlenbergia angustifolia Swallen, N. Amer. Fl. 17(6):457. 1935. TYPE: MEXICO. JALISCO: rocky hills near Guadalajara, 11 Nov 1889, C.G. Pringle 2346 (holotype: US-822882!; isotypes: LE!, MO-1837815!, US-995828!, US-3274342 fragm!). Caespitose perennials. Culms 100-180 cm tall, erect, glabrous to pubescent below the nodes; internodes glabrous. Leaf sheaths 8-42 cm long, longer than the internodes below, glabrous, the keels prominent, sometimes coiled to shredded below, basal sheaths compressed-keeled; sheath auricles 0.4-2.6 cm long on lower portions and up to 6.4 cm long above; ligules 4-15 mm long, membranous, apex finely lacerate some- times almost to base; blades 18-90 cm long, 2-7 mm wide, flat or folded, scaberulous to scabrous above and below, the margins and keel saw-toothed. Panicles 35-70 cm long, 4-15 cm wide, densely-flowered, oblong, sometimes lax near apex, greenish-brown, sometimes reddish-purple; primary branches 2-15 cm long, without spikelets near base, appressed to loosely spreading up to 60 from the rachises; pedicels 0.2-4 mm long, glabrous to scaberulous. Spikelets 1.5-2.8 mm long, erect, greenish-brown, to reddish-purple; glumes 1.2-2.8 mm long, longer, as long or a little shorter than the lemma, subequal, oblong to narrowly-oblong, faintly 1-nerved, hyaline, glabrous to scaberulous, usually with faint, widely scattered hairs, the hairs less than 0.1 mm long, apex acute to acuminate; upper glumes rarely mucronate, the mucro up to 0.4 mm long; lemmas 1.4-2.7 mm long, lanceolate to linear-lanceolate, awned, glabrous or sometimes the margins on the lower 1/3 pubescent, the hairs up to 0.2 mm long, rarely the lower 1/3 with scattered hairs, callus usually short pilose, apex acute, minutely bifid, the teeth up to 0.5 mm long, the awn 4-16 mm long, flexuous, often reddish-purple near base; paleas 1.3-2.7 mm long, glabrous or with a few hairs between the nerves on the lower 1/3, apex acute; anthers 1.2-1.5 mm long, yellowish, sometimes reddish tinged. Caryopses not seen. Chromosome number unknown. Phenology.?Flowering late September through December. Distribution and habitat.?Muhlenbergia distichophylla occurs from central Mexico in Jalisco, Guerrero, Mexico, Oaxaca, Chiapas to Guatemala; found in open pine-oak forests and tropical deciduous forests on rocky slopes, canyons, and ravines, with Pinus sp., Quercus spp., Arbutus sp., Dioon sp., Dasylirion sp., and Agave sp.; 400-2000 m. 954 Journal of the Botanical Research Institute of Texas 1(2) FIG. 7. Muhlenbergia distichophylla [LO. Williams 22309, A. MolinaR. & IP. Williams (US) & F.W. Gould 12666 (TAES, US)]. A. Ligule. B. Glumes. C. Floret. Muhlenbergiastricta[P.M. Peterson 8124 & R.M. King (US)]. D. Habit. E. Panicle. F. Ligule. G. Glumes. H. Floret. Peterson et al., Muhlenbergiinae from northeastern Mexico 955 Comments.?Morphological differences among many species of Muhlenbergia subg. Trichochloa sect. Epicampes, of which M. distichophylla is a member, are very minimal. In NE Mexico the following seven spe- cies represent this section: M. distichophylla, M. emersleyi, M. jaime-hintonii, M. lindheimeri, M. pubescens, M. pubigluma, and M. robusta. Preliminary molecular analyses of both nuclear and chloroplast DNA sequences also exhibits little variation among members of this section, perhaps indicating that current species delimi- tation is too fine-grained (Peterson et al. 2001a, 2004). Specimens examined. MEXICO. Tamaulipas: 42 km SW of hwy 85 on road towards Dulces Nombres, P.M. Peterson 15913 cvj. Valdes- Reyna (ANSM, US); 14.6 mi NE of Dukes Nombres, P.M. Peterson 15921 &}. Valdes-Reyna (ANSM, US). 10. Muhlenbergia dubia E. Fourn., Biol. Cent.-Amer., Bot. 3(29): 540. 1885. (Fig. 8, A-C). TYPE: MEXICO. OAXACA: Chinantla, May 1841, EM. Liebmann 688 (HOLOTYPE: P!; ISOTYPES: C, US-91018 fragm!). Muhlenbergia acuminata Vasey, Bot. Gaz. ll(12):337-338. 1886. TYPE: U.S.A. NEW MEXICO: probably Grant Co. near Santa Fe (fide Allred, Great Basin Naturalist 50:75. 1990), 1851-1852, C. Wright 1993 (HOLOTYPE: US-81605!; ISOTYPES: GH, US-995177!). Spoivbolus ligulatus Vasey & L.H. Dewey, Contr. U.S. Natl. Herb. 1(8): 268. 1893. TYPE: U.S.A. TEXAS: Presidio Co.: Limpia Canon, Sep 1892, G.C. Nealley 127 (HOLOTYPE: US-82018!; ISOTYPE: US-556887Q. Muhlenbergiafirma Beal, Grass. N. Amer. 2:243. 1896. TYPE: MEXICO. OAXACA: Sierra de San Felipe, summit ledges, 10,500 ft, 18 Sep 1894, C.G. Pringle 4914 (HOLOTYPE: MSC; ISOTYPES: LEI, MO-2974120!, US-746252!, US-822866!, US-250841!; W-1895-4473Q. Muhlenbergia densiflora Scribn. Sr Merr., Bull. Div. Agrostol., U.S.D.A. 24:18, f. 4. 1901. TYPE: MEXICO. DISTRITO FEDERAL: Serrania de Ajusco, on lava beds, 10,000 ft, 13 Aug 1897, C.G. Pringle 6675 (HOLOTYPE: US-316900!; ISOTYPES: CM-279867, LEI, US-822867!: W-1898-2942!). Crypsinna breviglumis M.E. Jones, Contr. W Bot. 14:8. 1912. TYPE: MEXICO. CHIHUAHUA: Guayanopa Canyon, Sierra Madre Mountains, Sep 1903, M.E. Jones s.n. (HOLOTYPE: POM?; ISOTYPE: US-3168555 fragm!). Densely caespitose perennials. Culms 30-100 cm tall, erect, rounded near the base, not rooting at the lower nodes; internodes glabrous for most of their length, minutely pubescent to hirtellous below the nodes. Leaf sheaths longer than the internodes, smooth or scaberulous, not becoming spirally coiled when old, rounded basally; ligules 4-10 mm long, membranous, firm below, acute, lacerate, brownish; blades 10-60 cm long, 1-2 mm wide, usually involute (occasionally flat), scabrous abaxially, hispidulous adaxially. Panicles 10-40 cm long, (0.6-)l-2.4 cm wide, contracted, grayish-green; primary branches 0.6-7 cm long, diverging up to 40? from the rachises, stiff, spikelet-bearing to the base; pedicels 0.1-6 mm long, strongly divergent, hispidulous. Spikelets 3.8-5 mm long, grayish green; glumes (1.8?)2?3 mm long, equal, shorter than the florets, glabrous and smooth proximally, scaberulous distally, faintly 1-nerved, acute; lemmas 3.8-5 mm long, narrowly lanceolate, calluses hairy, hairs to 0.5 mm long, lemma bodies glabrous and smooth below, scabrous distally, apices acuminate, unawned, mucronate or awned, the awns 1-6 mm long, straight; pa- leas 3.8-5 mm long, narrowly lanceolate, glabrous below, acuminate; anthers 1.5-2.2 mm long, greenish. Caryopses 2.5-3.5 mm long, fusiform, brownish. In = 40, 50. Phenology.?Flowering July to November. Distribution and habitat.?Muhlenbergia dubia grows on steep slopes, ridge tops, limestone rock outcrops, and along draws with Juniperusfiaccida, ]. deppeana, Quercus spp., Pinus ponderosa, P. edulis, P. pseudostrobus, P. johannis, Arctostaphylos pungens, Cercocarpus breviflorus, Fallugia paradoxa, Panicum bulbosum, Piptochaetium fimbriatum, Lycurus phleoides, Buddleja scorpioides, Nassella tenusissima, Juglans sp., Selaginella sp., Dasylirion sp., Hechtia sp., Opuntia spp., Salvia sp., Brahea sp., Agave sp., Yucca sp., Bouteloua hirsuta, B. unioloides, and Aristida spp.; 1500-3200 m. The range of M. dubia extends into the western Texas and southern New Mexico, U.S.A., and in Mexico this species occurs in Chihuahua, Durango, Aguascalientes, Zacatecas, Michoacan, Mexico, Distrito Federal, Tlaxcala, Guanajuato, Queretaro, Jalisco, Hidalgo, San Luis Potosi, Puebla, Vera- cruz, and Oaxaca (Espejo Serna et al. 2000). Comments.?Muhlenbergia dubia is morphologically similar to M. rigens and can be separated from the latter by having a more loosely ascending and wider panicles (up to 2.4 cm wide), longer panicle branches (up to 7 cm long), olivaceous anthers (verses reddish), longer lemmas, and shorter glumes (less than 3 mm long). Traditionally, M. firma was recognized as having longer ligules, a dense spike-like panicle verses a narrow but scarcely spikelike, and glume apices that are sub-aristate verses obtuse. All of these characters 956 Journal of the Botanical Research Institute of Texas 1(2) FIG. 8. Muhlenbergia dubia [P.M. Peterson 8384&J. Valdes-Reyna (ANSM, US)]. A. Ligule. B. Glumes. C. Floret. Muhlenbergiarigida [P.M. Peterson 9659 (US)]. D. Habit, E. Panicle (narrow). [P.M. Peterson 10876, C.R. Annable&l. Valdes-Reyna (US, ANSM)]. F. Panicle (wide). G. Ligule. H. Glumes. I. Floret. Peterson et al., Muhlenbergiinae from northeastern Mexico 957 vary on a single individual and within a population, and there appears to be very little correlation between distribution and morphology. Therefore, it seems best to recognize a single species. Our observations show as one descends in latitude from the U.S.A. and into Mexico a general trend is seen in the coloration of the panicles/spikelets. The northern forms are usually greenish-gray whereas the forms from Chihuahua south and east are often dark-reddish or greenish-gray. The type, from Oaxaca, is the greenish-gray form. Usually the dark-reddish forms tend to have slightly longer florets. Specimens examined. MEXICO. Couhuilu: 2?3.5 mi E of Hwy 54 up San Lorenzo Canyon, P.M. Peterson 13260, 13264, J. Valdes-Reyna 6 M.B. Knowles (US); Sierra El Pino, 33.5-39.5 km W of Rancho El Cimarron, P.M. Peterson 10659, 10665, 10689 & C.R. Annable (US); 140.3 km NW of Muzquiz on Hwy 53 towards Boquilla del Carmen, P.M. Peterson 10593, 10594 & C.R. Annable (US); 4 km E of Los Lirios on road to Laguna de Sanchez, 50 km SE of Saltillo, P.M. Peterson 6250 & C.R. Annable (US); 9.7 km E of Los Lirios on road to Laguna de Sanchez, 56.3 km SE of Saltillo, P.M. Peterson 6256 & C.R. Annable (US); 12.9 km E of Los Lirios on road to Laguna de Sanchez, 60 km SE of Saltillo, P.M. Peterson 6261 & C.R. Annable (US); Sierra Zapaliname, ca. 5 km east of Saltillo (Las Palapas) up Camino de Quatro; then up trail towards cumbre, P.M. Peterson 17862, 17866,]. Valdes-Reyna & R.H. Cardenas (ANSM, US); entrance to Monterreal, at 33mi E of Arteaga, P.M. Peterson 15944 &J. Valdes-Reyna (US); Municipio de Acufia, Serranias del Burro, Rancho El Bonito, Canon El Bonito, 7 mi W of la casa principal, J. Valdes-Reyna 235 & D. H. Riskind (ANSM); Serranias del Burro, Rancho El Bonito, Canon el Toro, J. Val- des-Reyna 1173 & D. H. Riskind (ANSM); Serranias del Burro, Rancho El Bonito, Canon Los Ojitos, j. Valdes-Reyna 1259 & D. H. Riskind (ANSM); Municipio de Arteaga, 32 mi SE of Saltillo & 8 mi SE of Jame, camino towards Las Vigas, P.M. Peterson 10058, C.R. Annable &>J. Valdes-Reyna (ANSM, US); 55.3 km SE of Saltillo and 16.6 km SE of Jame on road to Sierra La Viga, P.M. Peterson 10064, C.R. Annable &]. Vdldes-Reynrt(US);Jame-Rayones, G.S. Hinton 27809 (HINT); El Coahuilon, Sierra de la MartaJ. Valdes-Reyna 1835, M. A. CarranzaP. & J.A. Villarreal Q. (ANSM); Fraccionamiento Bravo Leon, E. Perez-Torres 3 (COCA); Las Vigas, Canon de la Carbonera, Sierra de Arteaga, J. Valdes-Reyna 1792, M.A. Carranza P. &J.A. Villarreal Q. (ANSM); Rancho el Chorro, carretera al Tunal, 3 km E de la desviacion al Tunal, sobre la carretera de Saltillo-Matehuala, J. Espinosa-Aburto 168 (ANSM); Sierra de Arteaga, Canon La Carbonera, camino al Tunal, M.A. Carranza P. 2436 & N. Snow (ANSM); Sierra de Arteaga, El Tunal, carretera estatal 65, P.S. Hoge. 267, M.E. Barkworth &J. Valdes-Reyna (ANSM); Sierra Madre Oriental. SE of San Antonio de las Alazanas and SE of Saltillo at end of road near summit of Coahuilon, P.M. Peterson 8384 & 8391, J.A. Villarreal Q. & j. Valdes-Reyna (ANSM, US); Municipio de Ramos Arizpe, Sierra de la Paila, Ejido el Cedral camino hacia el Valle de Parrerios, J.A. Villarreal Q. 5380, M.A. Carranza P. & A. Rodriguez G. (ANSM); Sierra de la Paila, Ejido el Cedral por el camino El Carmen, J. Valdes-Reyna 2184 (ANSM); Municipio de Saltillo, Canada Salsipuedes, en la Sierra Zapaliname, 3 km NO de Cuahtemoc, R. Lopez-Aguillono s.n. (ANSM); Canon de San Lorenzo, en la Sierra de Zapaliname, 8 km S de Saltillo, 3.2 km E de la Universidad Autonoma Agraria Antonio Narro, R. Lopez-Aguillon s.n. (ANSM); ca. 6 km S of Saltillo, land owned by Universidad Au- tonoma Agraria Antonia Narro, P.M. Peterson 8344 &J. Valdes-Reyna (US); "Lomas de Lourdes, PA. Lobato 5 (COCA); highway 54 (road from Saltillo to Concepcion del Oro), S of Estacion Carneros on telephone line service road, M.E. Barkworth 5122, J. Valdes-Reyna, P. 5. Hoge & M.A. Carranza P. (ANSM); 24.2 km S of Saltillo on MEX 54, 16.1 km E to Rancho Experimental Ganadero, P.M. Peterson 8434 &> M.A. Carranza P. (US); Rancho Experimental Los Angeles, 48 Km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, S.L. Hatch Stephen 4551, C.W. MordenJ. Valdes-Reyna (ANSM); 21 km SE of Saltillo on Hwy 57 towards Matehuala, P.M. Peterson 15799 cvj. Valdes-Reyna (US); Sierra de Zapaliname, 1 km S del Canon de San Lorenzo, R. Lopez-Aguillon s.n. (ANSM); Sierra de Zapaliname; Lomas de Lourdes, al SE de Saltillo, J.S. Marroquin delaEuente 2951 (ANSM); Sierra la Concordia, 40 km SO de Saltillo, J.A. Villarreal Q. 6567, M.A. Carranza P., J. Valdes-Reyna, M. Vdsquez R. & D. E. Lozano (ANSM); Sierra la Concordia, 6 km NE de la Victoria, J.A. Villarreal Q. 4084, M.A. Carranza P. & A. Rodriguez G. (ANSM); Sierra Madre Oriental, 18 mi S of Saltillo on Mexico 54 and 1.3 Mi W on road to microondas, just W of Estacion Carneros, P.M. Peterson 8419 & M.A. Carranza P. (ANSM, US); Sierra Madre Oriental. Cuesta de Palmas Altas, R. Marie Francois 5748 &J. Passini (ANSM); 5 mi W of Chapultepec on cutoff road between Hwy 54 & 57, 23 mi S of Saltillo, P.M. Peterson 13274, 13277 &M.B. Knowles (US). Nuevo Leon: 3 mi NE of Duke Nombres, 5.2 mi SE of San Pablo and 4 mi NW of San Francisco Javier, P.M. Peterson 18958 &J. Valdes-Reyna (ANSM, US); Sierra El Pinal Alto, 1.1 mi N of San Pablo, P.M. Peterson 18937, 18941 &J. Valdes-Reyna (ANSM, US); Sierra El Pinal Alto, 3.7 mi N of San Pablo, P.M. Peterson 18946 &>J. Valdes-Reyna (ANSM, US); 16 km W of Laguna de Sanchez and 21 km E of Los Lirios, P.M. Peterson 6272 & C.R. Annable (US); 2.5 mi N of La Siberia on road towards La Encantada, P.M. Peterson 16775, J. Valdes-Reyna & M. Sosa Morales (US); 5.2 mi S of Zaragoza on road towards Ejido La Encantada , P.M. Peterson 16749, J. Valdes-Reyna &M. Sosa Morales (US); Sierra La Lagunita; 9.5 mi SE of Aramberri on road towards Agua Fria, P.M. Peterson 16695, J. Valdes-Reyna & M. Sosa Morales (US); 13.5 mi SE of Aramberri on road towards Agua Fria, P.M. Peterson 16731, J. Valdes- Reyna & M. Sosa Morales (US); 8 km S of La Cruata on Hwy 3 towards Aramberri, P.M. Peterson 15885, 15887 &J. Valdes-Reyna (US); 2 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13319, 13321 & M.B. Knowles (US); 6.7 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13328, 13330 & M.B. Knowles (US); 10.4-12.7 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13331,13339,13342,13356 & M.B. Knowles (US); Municipio de Galeana, San Jose del Rio, G.S. Hinton 21508 (HINT); Canon de los Capulines above San Enrique, Hacienda San Jose de Raices, H.C. Mueller 2367 (MEXU); Cienegas del Toro, J.L. Elizondo-Elizondo 204 &> R. Banda S. (ANSM); Sierra el Infiernillo, Canon San Francisco, 15 km NE de Pablillo, J. Valdes-Reyna 2324, M.A. Carranza P. & R. Banda S. (ANSM); Municipio de General Zaragoza, Sierra El Soldado, camino a Puerto Pinos, J.A. Villarreal Q. 4957, M.A. CarranzaP., G. Nesom &J. Norris (ANSM, MEXU); Municipio de Iturbide, 10 mi W of Iturbide, J. Brunken. 202 & C. Perino (TAES); Municipio de Linares, Las Palmas-El Pinal, JJ. Ortiz-Diaz 21 (ANSM); Municipio de Santiago, Areas cercanas a Cola de Caballo, 958 Journal of the Botanical Research Institute of Texas 1(2) ].A. Villarreal Q. 5556 &M.A. Carranza P..(ANSM); La Escondida, I. Cabral-Corderol 592 (ANSM); Laguna de Sanchez, P. jauregui-Ramirez 127 (COCA). Tamaulipas: 42 km SW if hwy 85 on road towards Dulce Nombres, P.M. Peterson 15914 &]. Valdes-Reyna (ANSM, US); 14.6 mi NE of Dulce Nombres, P.M. Peterson 15920 &]. Valdes-Reyna (ANSM, US); 101.6 km SW of Ciudad Victoria on MEX 101 towards San Luis Potosi, P.M. Peterson 8326 ev R.M. King (US); Municipio de Bustamante, Ejido Felipe Angeles 2 km NO rumbo a Bustamante, R. Diaz-Perez 187 (UAT); Municipio de Hidalgo, Los Caballos, G.S. Hinton 24809 (HINT); Los Caballos, G.S. Hinton 24809 (MEXU), G. Villegas-Dumn 537 (COCA); Municipio de Jaumave, Ejido Avila & Urbina,].G. Galvdn-lnfante 103 (COCA); Municipio de Palmillas, Ejido Palmillas, R.A. Carranco-Rendon. 197 (COCA); Municipio de Tula, Valle de Tula, G. Villegas-Duran 544 (COCA). 11. Muhlenbergia emersleyi Vasey, Contr. U.S. Natl. Herb. 3(1):66. 1892. (Fig. 9, A-C). Epicampes emersleyi (Vasey) Hitchc, U.S.D.A. Bull. (1915-23) 772:44-145. 1920. TYPE: U.S.A. ARIZONA: 1890,].D. Emersley 46 (HOLOTYPE: US-73223!). Muhlenbergia vaseyana Scribn., Ann. Rep. Missouri Bot. Gard. 10:52. 1899. TYPE: U.S.A. ARIZONA: Jul 1874, J.T. Rothroch 282 (LECTOTYPE: US-81633! designated by Soderstrom, Contr. U.S. Natl. Herb 34(4): 166. 1967, without citing a specific sheet in a specific her- barium). Epicampes subpatens Hitchc, U.S.D.A. Bull. (1915-23) 772:144. 1920. TYPE: U.S.A. NEW MEXICO: Eddy Co.: Ranger Station, Queen, Guadeloupe Mountains, 3-6 Sep 1915, AS. Hitchcock 13541 [Amer. Gr. Herb. 1382] (HOLOTYPE: US-905799!; ISOTYPES: LE!, US- 3215629!, US-3278409Q. Muhlenbergia distans Swallen, N. Amer. Fl. 17(6):461. 1935. TYPE: MEXICO. Oaxaca: Las Sedas, dry hills, 6000 ft, 15 Sep 1894, C.G. Ptingle 5575 (HOLOTYPE: US-746297!; ISOTYPES: MO-1837832!, TAES!, US-134322!, US-305676!). Muhlenbergia gooddingii Soderstr., Contr. U.S. Natl. Herb. 34(4):115. 1967. TYPE: U.S.A. ARIZONA: Pima Co.: Baboquivari Mountains, canyon north of Moristo Canyon, 4000 ft, 19 Nov 1945, LN. Goodding 462-45 (HOLOTYPE: YU; ISOTYPES: ARIZ!, MO-5073874!, NY, US-2550348!). Densely caespitose perennials. Culms (65-)80-150(-200)cm tall, erect, stout, not conspicuously branched; internodes smooth lor most oi their length, smooth or scaberulous below the nodes. Leaf sheaths 7-35 cm long, shorter or longer than the internodes, glabrous or puberulent, basal sheaths compressed-keeled, usu- ally keeled; sheath auricles lacking; ligules 10-25 mm long, membranous throughout, acuminate, lacerate, slightly firmer below; blades 20-50 cm long, 2-6 mm wide, flat or folded, scabrous abaxially, smooth or scaberulous adaxially, margins coarsely scabrous. Panicles 20-45 cm long, 3-15 cm wide, loosely contracted to open, light purplish to light brownish; primary branches 1-17 cm long, lax, loosely appressed or diverging up to 70? from the rachises, naked basally; pedicels 0.5-3 mm long, erect, smooth or scaberulous. Spikelets 2.2-3.2 mm long; glumes 2.2-3.2 mm long, longer or as long as the lemma, subequal, scaberulous to scabrous, faintly 1-nerved, acute to obtuse, usually unawned, occasionally mucronate, mucro to 0.2 mm long; lemmas 2-3 mm long, oblong-elliptic, pubescent along the midvein and margins on the lower V4?%, apices acute, usually awned, sometimes unawned and or mucronate, awns generally (1?)6?15 mm, flexuous, purplish; paleas 1.8-2.9 mm long, oblong-elliptic, acute; anthers 1.2-1.6 mm long, yellowish to purplish. Caryopses 1.3-1.6 mm long, fusiform, reddish-brown. In = 24, 26, 28, 30, 40, 42, 46, 60, 64. Phenology.?Flowering July to November. Distribution and habitat.?Rocky slopes, gravelly washes, canyons, cliffs, and along streams often derived from limestone parent material associated with Quercus spp., Pinus cembroides, P. chihuahuana, P. jefjeryi, P. ponderosa, P. edulis, P. rejlexa, juniperus deppeana, Arctostaphylos pungens, A. patula, Ceanothus leucodermis, Agave sp., Prosopis sp., Plantanus wrightii, Rhus trilobata, Cercocarpus breviflorus, Chilopsis linearis, Fallugiaparadoxa, and Bouteloua curtipendula; 1200-2600 m; western Texas, New Mexico, Arizona and common throughout Mexico. Comments.?Muhlenbergia emersleyi is an extremely variable species. Soderstrom (1967) pointed out that M. emersleyi is the most common species of Muhlenbergia sect. Epicampes and that, "attempts to segregate the forms into more than one species on the basis of morphology are unrewarding because of a thorough intergradation of characters among the specimens." Preliminary molecular evidence seems to support this conclusion because there apparently is very little sequence divergence among closely related species of this section (Peterson et al. 2001a, 2004). Specimens examined. MEXICO. Coahuila: 26 mi E of Saltillo, J.R. Reeder 3289, C.G. Reeder&> J.R. Soderstrom [n=30](US); Municipio de Acuha, del Carmen mountains, E.G. Marsh Jr. 655 (MEXU); Serranias del Burro, Rancho El Bonito, Cafion El Bonito, 7 mi O de la casa principal, en la ultima pila, J. Valdes-Reyna 1237, D.H. Rishind (ANSM); Serranias del Burro, Rancho El Bonito, Canon el Toro, R. Valdes- Reyna 1174 & D.H. Rishind (ANSM); Municipio de Arteaga, 12 km de Saltillo, hacia Matehuala, M.A. Madrigal-A. s.n. (ANSM); 17 mi SE Peterson et al., Muhlenbergiinae from northeastern Mexico 959 FIG. 9. Muhlenbergia emersleyi [J.R. Reeder7393 & C.G. Reeder (ARIZ, US)]. A. Ligule. B. Glumes. C. Floret. Muhlenbergialindheimeri (P.M. Peterson 6280 & C.R. Annable (US)]. D. Habit. E. Ligule. F. Glumes. G. Floret. 960 Journal of the Botanical Research Institute of Texas 1(2) of Saltillo & 7.4 mi NW of Jame, P.M. Peterson 10077 (ANSM, US); Sierra de Arteaga, El Tunal, carretera estatal 65, P.5. Hoge 263, M.E. Barkworth &>]. Valdes-Reyna (ANSM); Municipio de General Cepeda, km 23 Carretera de General Cepeda a Parras, J. Espinosa-Aburto 154 (ANSM); Municipio de Ramos Arizpe, Sierra de la Paila (Lado Norte) Canada Becerros, J.A. Villarreal Q. 5464, M.A. Carranza P. & L. Avce G. (ANSM); Municipio de Saltillo, Estacion Carneros, carretera a Zacatecas 30 km S de Saltillo, M.A. Carranza P. 515 & P.M. Peterson (ANSM); Rancho experimental Los Angeles, 48 km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, J.A. Villarreal Q. 3370, ]. Valdes-Reyna (ANSM); Sierra la Concordia, 6 km NE de la Victoria, J.A. Villarreal Q. 4083, M.A. Carranza P. e> A. Rodriguez G. (ANSM); Sierra Madre Oriental, Sierra Zapaliname, 1 km S del Canon de San Lorenzo, R. Lopez-Aguillon s.n. (ANSM). Nuevo Leon: Municipio de Galeana, Agua Blanco a San Miguel, G.S. Hinton 21337 (HINT); A orillas del pozo el Gavilan, P. Jauregui-Ramirez 37 (COCA); Municipio de General Zaragoza, 4 km S of Zaragoza at jtn of road to Cerro Viejo-Tepehuanes, P.M. Peterson 15854 &>]. Valdes-Reyna (ANSM, US); 6 km S of Zaragoza, P.M. Peterson 15861 &]. Valdes-Reyna (ANSM, US); 8 km S of La Cruata on hwy 3 towards Aramberri, P.M. Peterson 15890 &]. Valdes-Reyna (US); 19 km S de Zaragoza, camino a La Encantada, J.A. Villarreal Q. 7539 e> M.A. Carranza P. (ANSM); Muni- cipio de Linares, Las Palmas-El Pinal, ].]. Ortiz-Diaz 53 (ANSM); Municipio de Santiago, Las Gracielas, I. Cabral-Cordero 552 (ANSM); San Jose de Las Boquillas, I. Cabral-Cordero 563 (ANSM). Tamaulipas: Municipio de Aldama, Ejido Lauro Aguirre, P. Moya-Salgado 246 (COCA); Municipio de Guemez, Camino a Los San Pedros, G. Villegas-Durdn 532 (COCA); Los Pedros, G.S. Hinton 25135 (HINT); Los Pedros a Hacienda La Boca, G.S. Hinton 25302 (HINT); Municipio de San Carlos, El Rosario. Vicinity of Marmolejo, H.H. Bartlett 10882 (MEXU); Municipio de Tula, 30 km al N de Tula, I. Nunez-Tancredi 28 (COCA); Municipio de Victoria, Altas Cumbres, G. Bores-Kidman 81 (COCA); Altas Cumbres, J.F. Iribe-Duarte 160 (COCA); Camino al Molino, J.E. Lopez de la Cruz 28 (COCA); Carretera Victoria-Tula, J.F. Iribe-DuarteJ. Fernando 44 (COCA); Ejido Vicente Guerrero, Cisneros M. 187 (COCA); Minas de asbesto, 35 km al O de Ciudad Victoria, F. Gonzdlez-Medrano 3423, P. Torres V. Soils & M. Terrazas (MEXU). 12. Muhlenbergia fragilis Swallen, Contr. U.S. Nad. Herb. 29(4):206. 1947. (Fig. 6, D-G). TYPE: U.S.A. TEXAS: Brewster Co.: Sunny Glen, W of Alpine, 29 Sep 1935, B.H. Warnoch 235 (HOLOTYPE: US-1829290!; ISOTYPE: GH!). Caespitose annuals. Culms 10-38 cm, erect or spreading; scabrous or strigulose below the nodes; internodes mostly glabrous, smooth or scaberulous. Leaf sheaths 2.4-4.2 cm long, often longer than the internodes, scaberulous, margins hyaline; ligules 1-3 mm long, hyaline, obtuse, irregularly toothed to lacerate, with lateral lobes extended into auricles; blades 1-10 cm long, 0.4-2 mm wide, flat, scabrous abaxially, strigulose adaxially, margins and midveins whitish-thickened; panicles 10-24 cm long, 3.5-11 cm wide, diffuse; primary branches 2.2-6.2 cm long, capillary, diverging 80-100? from the rachises, straight; pedicels 6-10 mm long, delicate. Spikelets 1-1.2 mm long, appressed to slightly divergent from branch axes; glumes 0.5-1 mm long, equal to subequal, glabrous throughout or obscurely puberulent, hairs about 0.06 mm long, 1-nerved, apex obtuse or subacute; lemmas 1-1.2 mm long, oblong-elliptic, membranous, purplish to light brownish, not mottled, glabrous or densely appressed-puberulent on the margins and midveins, apices obtuse, unawned; paleas 0.9-1.2 mm long, oblong-elliptic, densely puberulent between the nerves or glabrous, apex obtuse; anthers 0.3-0.5 mm long, purplish. Caryopses 0.7-0.9 mm long, elliptic, reddish-brown. In = 20. Phenology.?Flowering August through September. Distribution and habitat.?Muhlenbergia fragilis grows on rocky talus slopes, cliffs, canyon walls, road cuts, and sandy slopes, often on calcareous parent materials, at elevations of 480-2200 m; southeastern California to western Texas, U.S.A., and south in Mexico from Baja California, Sonora, Chihuahua, Sinaloa, Jalisco, Nayarit, Guanajuato, San Luis Potosi, Queretaro, Michoacan, Guerrero, Morelos, Puebla, Veracruz, Oaxaca, and Chiapas. It is usually found in oak-grama savannahs, thorn scrub forests, oak-yellow pine forests, and pinyon-juniper woodlands. Comments.?Occasionally populations may have some individual plants with completely glabrous lem- mas rather than the more common hairy-spikeleted forms. This morphological variation is not correlated with distributional or habitat preference. Specimen examined. MEXICO. Tamaulipas: San Antonio de los Alamos, E base of Sierra de San Antonio, I.M. Johnston 8244 (US, UT). 13. Muhlenbergia glauca (Nees) B.D. Jacks., Index Kew. 2:269. 1895. (Fig. 10, A-D). Podosemumglaucum Nees, Linnaea 19(6):689. 1847. TYPE: MEXICO. A. Aschenborn 335 (HOLOTYPE: B?). MuhlenbergiahuachucanaVasey, Contr. U.S. Natl. Herb. 3(1):69. 1892. TYPE: U.S.A. ARIZONA: Huachuca Mountains, Jul 1882, J.G. Lemmon 2915 (HOLOTYPE: US-81617Q. Muhlenbergia lemmonii Scribn., Contr. U.S. Natl. Herb. 1(2):56. 1890. TYPE: U.S.A. ARIZONA: Huachuca Mountains, Lemon and wife 2918 (LECTOTYPE: US-746111! designated by Hitchcock, N. Amer. Fl. 17(6):449. 1935, without citing a specific sheet or specific herbarium; ISOLECTOTYPES: US-994769!, US-994778!, US-746113!). Peterson et al., Muhlenbergiinae from northeastern Mexico 961 1mm FIG. 10. Muhlenbergia glaum [P.M. Peterson 6031 & C.R. Annable (US)]. A. Ligule. B. Glumes. C. Floret. D. Lodicules, stamens, and pistil. Muhlenbergia polycaulis [P.M. Peterson S647& C.R. Annable (US)]. E. Habit. F. Ligule. G. Glumes. H. Floret. I. Lodicules, stamens, and pistil. 962 Journal of the Botanical Research Institute of Texas 1(2) Perennials with slender, creeping, well-developed rhizomes. Culms 25-60 cm tall, 1-2 mm thick, often decumbent, moderately stiff, sometimes erect; internodes mostly scabrous, retrorsely hispidulous below the nodes. Leaf sheaths longer than the internodes, scaberulous; ligules 0.5-2 mm long, truncate to obtuse, erose or lacerate; blades 4-12 cm long, 1-2.6 mm wide, flat to involute distally, not arcuate, scabrous abaxially, hirsute or scabrous adaxially. Panicles 4-12(-17) cm long, 0.3-2.4 cm wide, contracted, interrupted below; primary branches 0.3-3 cm long, usually appressed, occasionally diverging up to 30? from the rachises; pedicels 0.1-1.2 mm long, scabrous to hirsute. Spikelets 2.4-3.5 mm long; glumes 1.5-3.5 mm long, Vz to about as long as the lemma, equal, 1-nerved, veins scabrous, apices acute or acuminate, usually mucronate or awned, awns, if present, to 1.5 mm long; lemmas 2.4-3.4 mm long, elliptic, pubescent on the lower the V2 of the midveins and margins, hairs to 0.6 mm long, tawny, apices acuminate to acute, awned, awns 0.1-3(-5) mm long, straight; paleas 2.2-3.4 mm, elliptic, intercostal region pubescent on the lower V2, apices acuminate to acute; anthers 1.8-2.4 mm long, orange. Caryopses 1.7-2 mm long, fusiform, brownish. In = 60. Phenology.?Flowering August through October. Distribution and habitat.?Calcareous rocky slopes, cliffs, canyon walls, table rocks, and volcanic rock outcrops in open vegetation associated with Quercus, Pinus cembroides, P. chihuahuana, Juniperus deppeana, Plantanus wrightii, Arctostaphylos pungens, Agave, Dasylirion, Yucca carnewsana, Rhus trilobata, R. glabra, Vitis arizonica, and Ceanothus buxifolius; 1200-2780 m; southeastern Arizona, southern New Mexico, southeastern Texas to northern Mexico, also found in Chihuahua, Durango, Aguascalientes, San Luis Potosi, Mexico, Distrito Federal, Guanajuato, Hidalgo, Jalisco, and Puebla (Espejo Serna 2000; Herrera Arrieta 2001; Peterson 2003). Comments.?Muhlenbergia glauca is morphologically very similar to M. polycaulis and can be distinguished from that species by its shorter awned lemmas (the awn usually less than 3 mm long) and slender, well developed rhizomes. More study of these two species, along with the allied, M. arsenei and M. pauciflora, is needed. Specimens examined. MEXICO. Coahuila: Sierra del Paila, Oct 1910, C.A. Put pus 5006 (US); Western Coahuila, Sierra de la Madera. vicinity of "La Cueva" in Corte Blanco fork of Charretera Canyon, 5300?6500 ft, LM. Johnston 8906 (US); UAAAN experimental ranch "Los Angeles" 14 km E of Mex Hwy 54, 30 km S of Saltillo, C.W. Morden 515 (US); Sierra El Pino, 33.5 km W of Rancho El Cimarron, P.M. Peterson & C.R. Annable 10655 (US); Sierra El Pino, 40.3 km W of Rancho El Cimarron, P.M. Peterson & C.R. Annable 10664 (US); Sierra El Pino, 39.5 kmW of Rancho El Cimarron, P.M. Peterson cy C.R. Annable 10668 (US); Municipio de Acuha, Serranias del Burro, Rancho El Bonito, 12 km O de la casa del rancho El Bonito, Canon Los Ojitos,J. Valdes-Reyna 1264 & D. H. Riskind (ANSM); Municipio de Arteaga, 17 mi SE of Saltillo & 7.4 mi NW of Jame, at Bosques de Montana (near cabin of J. Valdes-Reyna), P.M. Peterson 10072, C.R. Annable &>]. Valdes-Reyna (ANSM, US); 6 Km E del entronque carretera 57 hacia los Lirios, J.A. Villarreal Q.l 5173, J. Valdes-Reyna, M.E. Barhworth & P.S. Hoge (ANSM); Bosques de Montana, aproximadamente 6 Km E de carretera 57 camino a Jame, 30 Km SE de Saltillo, Valdes-Reyna Jesus 2361, J.A. Villarreal Q. & M.A. Carranza P. (ANSM); SE of San Antonio de las Alazanas and SE of Saltillo along road up Coahuilon, P.M. Peterson 8386, J. Valdes-Reyna &J.A. Villarreal (ANSM, US); Municipio de Muzquiz, Sierra La Encantada, aproximadamente 170 km NO de Muzquiz, cuesta de Malena, brecha Muzquiz-Boquillas del Carmen, M.A. Carranza P. 829, J. Valdes-Reyna, P.A. Fryxell, R. Vdsauez A. &>0. Meza (ANSM); Municipio de Ramos Arizpe, Sierra de la Paila, Ejido el Cedral camino hacia el Valle de Parrehos, J.A. Villarreal Q. 5284, M.A. Carranza P. & A. Rodriguez G. (ANSM); Municipio de Saltillo, Canon de San Lorenzo, en la Sierra de Zapaliname, 8 km S de Saltillo, 3.2 km E de la Universidad Autonoma Agraria Antonio Narro, R. Lopez-Aguillon s.n. (ANSM); Canon de Zapaliname, en la Sierra Zapaliname, 8 km S de Saltillo & 3.2 km E de Buenavista, Saltillo, L. Aree-Gonzdlez s.n. (ANSM); Sierra Zapaliname, 1 k S del Canon de San Lorenzo, R. Lopez-Aguillon s.n. (ANSM). Nuevo Leon: Municipio de Aramberri, Carretera Galeana-La Ascension, a 1.5 km del poblado de San Enrique en Galeana, M.M. Castillo-Badillo 209 & N. Bazaldua B. (COCA); Municipio de Linares, Las Palmas-El Pinal, J.J. Ortiz-Diaz 22 (ANSM); Municipio de General Zaragoza, 6 km S of Zaragoza, P.M. Peterson 15871 &]. Valdes-Reyna (ANSM, US). 14. Muhlenbergia gypsophila Reeder &C. Reeder, Madrono 18:186-190, f. 1 Al-Hl. 1966. (Fig. 11, A-F) TYPE: MEXICO. NUEVO LEON: 3 mi E of junction of Linares-Galena road with Hwy. 85, 6400 ft, 30 Oct 1964, J.R Reeder & C.G. Reeder 3963 (HOLOTYPE: YU; ISOTYPE: US-2524092Q. Densely caespitose perennials. Culms (12-)25-80 cm tall, erect, pubescent below the nodes, the basal nodes terete, 2-4 nodes per culm; internodes scabrous. Leaf sheaths (4-)8-22 cm long, shorter or longer than the internodes, pubescent to glabrous basal sheaths rounded becoming brownish, shredded and/or fibrous with age; ligules l-6(-10) mm long, membranous above and firm and light brown below, decurrent, margins puberulent, apex truncate, acute or acuminate; blades 2-14(-25) cm long, 0.5-1.5 mm wide, tightly involute, Peterson et al., Muhlenbergiinae from northeastern Mexico 963 1mm FIG. 11.Muhlenbergiagypsophila[P.M.Peterson6235&CR.Annable(US)]. A. Habit. B. Panicle.C.Ligule. D. Glumes. E. Floret. F. Lodicules,stamens,and pistil. Muhlenbergiapurpusii [P.M. Peterson 6227& C.R. Annable (US)]. G. Habit. H. Panicle. I. Ligule. J. Glumes. K. Floret. L. Lodicules, stamens, and pistil. 964 Journal of the Botanical Research Institute of Texas 1(2) somewhat rigid and falcate, scabrous to glabrous below and densely pubescent above, the hairs less than 0.1 mm long. Panicles (3-)5-18(-22) cm long, 0.2-1 cm wide, contracted, spikelike, dense, stramineous to purplish; primary branches 0.5-2.7 cm long, ascending and tightly appressed; pedicels 0.6-2.6 mm long, shorter than the spikelets, scabrous. Spikelets 3.5-4.3 mm long, stramineous to purplish; glumes 1.2-2.5 mm long, shorter than the floret, obscurely 1-nerved, puberulent on upper 2/3, apex acute often erose; lemmas 3.5-4.3 mm long, lanceolate, stramineous to purplish, lateral nerves distinct and raised, short pi- lose throughout, the hairs 0.1-0.3 mm long, callus densely short pilose, apex acute to acuminate, entire to minutely bifid, awned, the awn 10-20 mm long, flexuous; paleas 3.5-4.3 mm long, as long as the lemma, short pilose between the nerves throughout, apex acute; anthers 1.5-2.4 mm long, greenish to purplish. Caryopses 1.7-2.1 mm long, fusiform, light brownish. In = 20. Phenology.?Flowering September through November. Distribution and habitat.?Muhlenbergia gypsophila occurs on calcareous derived soils primarily on gypsum flats usually on the sides of sink holes, roadsides, and slopes with Flaveria sp., Larrea divaricata, Prosopis sp., Pinus cembroides, Pinus spp., Bouteloua chasei, B. gracilis, B. uniflora, Muhlenbergia purpusii, Acacia sp., Puya sp., Agave lecheguilla, Juniperus flaccida, Rhus sp., Dasylirion longissimum, Condalia sp., Leucophyllum alejandrae, L. hintonii, Gutierrezia microphylla, Aristida spp.Yucca carnerosana, Quercus spp., and Brichellia sp.; 1025-2430 m. Specimens examined. MEXICO. Coahuila: Municipio de Cuatrocienegas, entrada al Casco del Rancho Potrero de Menchaca, R. Vasauez- Aldape 17 cy L.E. Rodriguez G. (ANSM); along road to Concepcion de Oro, Zacatecas, 35 mi S of Saltillo, J.R. Reeder &> C.G. Reeder 3622. Nuevo Leon: 2 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13318 &> M.B. Knowles (US); 36 mi NE of Dr. Arroyo on Hwy 61 towards Linares, P.M. Peterson 13367 &> M.B. Knowles (US); 8.7 miNE of San Antonia de Pena Nevada on road towards La Liberia, P.M. Peterson 16784, ].Valdes-Reyna& M. Sosa Morales (US); 13.5 mi S of Milagro, P.M. Peterson 17816,]. Valdes-Reyna & G.S. Hinton (US); 5.6 mi E of junction of Hwy 57 on Hwy 58 towards Linares, P.M. Peterson 13289, 13297, 13298 & M.B. Knowles (US); 13.4 miE of Hwy 57 on Hwy 58 at crossing of Rio Potosi, P.M. Peterson 13299 &M.B. Knowles (US); Municipio de Aramberri, Aramberri, G.S. Hinton 23999 (ANSM, HINT); La Escondida, Aramberri-Dolores, G.S. Hinton 23597, 23655 (ANSM, HINT); 12 km S of Aramberri, P.M. Peterson 15848 &]. Valdes-Reyna (US); Municipio de Galeana, Near Galeana, 25 Mar 1962, A.A. Beetle M-481 (US); 3 mi SE of Galeana, J.R. Reeder and C.G. Reeder 3659 (US); 10 km E del entronque a San Roberto sobre carretera 58 camino a Galeana, J. Valdes-Reyna 1721 & R. Banda S. (ANSM); 2 km S del Salero, 1 km E de carretera 57 Matehuala-Saltillo,]. Valdes-Reyna 1619 &].S. Marroauin de la F. (ANSM); 3kmSofElSalero, P.M. Peterson 17834,]. Valdes-Reyna & G.S. Hinton (US); 7.5 km E of Puentes, P.M. Peterson 17851,]. Valdes-Reyna & G.S. Hinton (US); 20 km S of San Roberto along highway 57, S.L. Hatch 4942, ]. Valdes-Reyna &]. Kessler (ANSM); 5 km E de Galeana, I. Cabral-Cordero 1082 (ANSM); 4 mi SE of Galeana, J.R. Reeder & C.G. Reeder 3965, 4987 (US); 1 mi S of Galeana, KW. Allied 5502, T. Columbus &]. Valdes-Reyna (ANSM); Ejido El Tokio, M.L. Avalos-Marin s.n. (UAT, ANSM); Galeana, ].A. Ochoa-Guillemar 1000 (COCA); La Becerra, G.S. Hinton 19868 (ANSM, HINT, MEXU); Santa Rita, 5 km S de Galeana,].A. Villarreal Q. 6319 & M.A. Carranza P. (ANSM); 3mi SE of Galeana on road to Linares, P.M. Peterson 13314 & M. B. Knowles (US); San Jose del Rio, G.S. Hinton 21531 (HINT); Pabillo a La Ascension, G.S. Hinton 27496 (HINT); SW of Laguna de Labradores, G.S. Hinton 27891, 28080(HINT); Municipio de General Zaragoza, Zaragoza, G.S. Hinton 23647, 23636 (ANSM, HINT); 12 km S of Aramberri, Cuesta Blanca near La Joya, P.M. Peterson 15840 &]. Valdes- Reyna (ANSM, US). 15. Muhlenbergia jaime-hintonii EM. Peterson & Valdes-Reyna, Sida 18(3):686, f. 1. 1999. (Fig. 12, A-L). TYPE: MEXICO. NUEVO LEON; Municipio General Zaragoza, La Joya, Cuesta Blanca, ca. 15 km S of Aramberri on road towards Zaragoza, 1345 m, 31 Oct 1998, J. Valdes-Reyna & M. A. Carranza Perez 2560 (HOLOTYPE: ANSM!; ISOTYPES: US-3377556!, US-33775570- Loosely caespitose perennials with short, densely leafy rhizomes and extravaginal shoot initiation. Culms 44-82 cm tall, erect, compressed keeled near the base, densely white pubescence below the basal nodes, these hidden beneath the leafy sheaths, the hairs 0.8-1.3 mm long, upper nodes glabrous or puberulent; internodes puberulent below and mostly glabrous above. Leaf sheaths 6-28 cm long, longer than the lower internode, puberulent to glabrous, stiff and brownish below, often curled, margins mostly smooth with a few short hairs near the summit; ligules 0.4-1 mm long, membranous below, apex truncate, ciliolate; blades 5-22 cm long, 1.8-5 mm wide, flat just above ligule to tightly conduplicate above, apically acuminate, somewhat stiff, pubescent above and glabrous below. Panicles 13-34 cm long, 0.7-7 cm wide, narrow to somewhat open, the ascending densely flowered branches tightly appressed or loosely spreading up to 40? from the rachises; primary branches 0.5-6.5 cm long; pedicels 0.5-2 mm long, ascending, scaberulous. Spikelets 1.5-2.1 mm long, appressed to branches, 1-flowered, reddish-gray; glumes 0.7-1.2 mm long, oblong, Peterson et al., Muhlenbergiinae from northeastern Mexico 965 FIG. 12. Muhlenbergiajaime-hintonii [J. Valdes-Reyna 2560 & MA CarranzaP. (ANSM, US)]. A. Habit. B. Ligule. C. Panicle. D. Secondary panicle branch. E. Spikelet. F. Glumes. G. Lemma. H. Lemma, opened. I. Lemma, lateral view. J. Palea. K. Palea with lodicules, stamens, and pistil. L. Lodicules, stamens, and pistil. Scale for C is shown in A; Scale for F-L is shown in E. 966 Journal of the Botanical Research Institute of Texas 1(2) shorter than the lemma, usually equal in length, faintly 1-nerved, reddish, glabrous, scaberulous along the midvein, apex acute to obtuse, occasionally minutely erose; lemmas 1.5-2.0 mm long, oblong to elliptic, unawned, faintly 3(l)-nerved, greenish mottled with reddish areas, midvein, margins, and proximal V2 to 3A loosely to densely appressed pubescent to villous, often these hairs more numerous along the margins and midvein below, the hairs up to 0.5 mm long, apex acute, rarely minutely mucronate; paleas 1.5-2.0 mm long, oblong, 2-nerved, equal in length to the lemma, the proximal 2/3 to 3A densely appressed pubescent to villous between the veins and along the margins, apex acute to obtuse; anthers 0.8-1.0 mm long, reddish at maturity, greenish when immature. Caryopsis not seen. Phenology.?Flowering in October through November. Distribution and habitat.?Muhlenbergia jaime-hintonii is known only from southern Nuevo Leon between 1300-1850 m in the Municipio's Aramberri and General Zaragoza, and can be found growing in whitish, alkaline soils derived from gypsum with Leucophyllum hintoniorum G.L. Nesom, Scutellaria lutilabia T.M. Lane & G.L. Nesom, Galium dempsterae B.L. Turner, Lobelia gypsophila TJ. Ayers, Geniostemon gypsophilum B.L. Turner, Callisia hintoniorum B. L. Turner, Agave striata Zucc, and Heehtia glomerata Zucc. Specimens examined. MEXICO. Nuevo Leon: Municipio de Aramberri, between LaEscondida and Aramberri, 23 Oct 1993, G.S. Hinton et al. 23707 (ANSM, HINT, US); San Francisco, G.S. Hinton 22698 (ANSM, HINT, TEX), G.S. Hinton 22725, 28234 (HINT); Municipio General Zaragoza, Aramberri-El Salitre, 26 Oct 1993, G.S. Hinton 23766 (ANSM, HINT, TEX); La Joya, Cuesta Blanca, approximately 15 km S of Aramberri on road towards Grab Zaragoza, 29 Jul 1998, M.A. Cananza P. C-2981 &J. Valdes-Reyna (ANSM); near La Joya, 12 km S of Aramberri, 20 Sep 2001, P.M. Peterson 15841 &]. Valdes-Reyna (ANSM, US). 16. Muhlenbergia lindheimeri Hitchc, J. Wash. Acad. Sci. 24(7):291. 1934. (Fig. 9, D-G). TYPE: U.S.A. TEXAS: 1847, F. Lindheimer 725 (HOLOTYPE: US-998949!; ISOTYPES: F, GH, MO!, UC, US-998947!, W!). Epieampesgraeilis Trin., Mem. Acad. Imp. Sci. Saint-Petersbourg, Ser. 6, Sci. Math., Seconde Pt. Sci. Nat. 6,4(3?4):271. 1841, nom. illeg. horn. TYPE: U.S.A. Texas oriental, Dec 1870, s.c. s.n. (HOLOTYPE: LE-TRIN-1556.01!). Strongly caespitose perennials. Culms 50-150 cm tall, stout, erect, not rooting at the lower nodes; internodes mostly glabrous, sometimes puberulent below the nodes. Leaf sheaths 10-45 cm long, shorter or longer than the internodes, glabrous, basal sheaths compressed- keeled, not becoming spirally coiled when old, pur- plish-brown or yellowish; ligules 10-35 mm long, decurrent, firm and brown basally, membranous distally, acuminate; blades 25-55 cm long, 2-5 mm wide, flat or folded, firm, scaberulous abaxially, often involute near apex, scabrous and shortly pubescent adaxially. Panicles 15-50 cm long, (0.6-)l-2(-3) cm wide, loosely contracted, often purplish-tinged; primary branches 0.5-7 cm long, appressed or strongly ascending, rarely spreading as much as 20? from the rachises; pedicels 0.5-1.2 mm long, scabrous. Spikelets 2.4-3.5 mm long, light grayish; glumes 2-3.5 mm long, equal, longer than the florets, scabrous or smooth, 1-nerved, obtuse to acute, occasionally bifid and the teeth to 0.3 mm long, unawned, rarely mucronate, mucros less than 0.2 mm long; lemmas 2.4-3.5 mm long, lanceolate, scabrous or smooth, rarely puberulent near the base, apices obtuse to acute, unawned or awned, the awns 1-4 mm long, straight; paleas 2.4-3.5 mm long, lanceolate, glabrous to puberulent between the nerves on the proximal Vt, obtuse; anthers 1.1-1.5 mm long, purplish. Caryopses 1.2-1.6 mm long, fusiform, reddish-brown. In = 20, 26, 30 (Reeder & Reeder 4577). Phenology.?Flowering August through December. Distribution and habitat.?Muhlenbergia lindheimeri grows in sandy draws to rocky, calcareous soils, generally in open areas, at elevations of 150-700 m. Muhlenbergia lindheimeri is an uncommon species throughout its range, which includes northern Mexico in addition to southern Texas, but it also is grown as an ornamental. Peterson & Valdes-Reyna 18957 from near San Pablo is an unusual collection of M. lindheimeri since it was collected at 2550 m. All other collections of this species are known from below 700 m. Comments.?Muhlenbergia lindheimeri is similar to M. pubigluma, another species with strongly com- pressed-keeled basal sheaths and decurrent ligules that are firm and brown below. Muhlenbergia lindheimeri can be separated from M. pubigluma by having glabrous glumes that are longer than the florets (verses short pubescent glumes, shorter than the florets in M. pubigluma) and lemmas that are glabrous, rarely puberulent (verses lemmas that are villous on lower Vi in M. pubigluma). Peterson et al., Muhlenbergiinae from northeastern Mexico 967 Specimens examined. MEXICO. Coahuila: 7 mi SSW of Cuatro Cienegas on road to San Pedro, J.R. Reeder cv C.G. Reeder 1577 (US): Municipio de Ramos Arizpe, Sierra de la Paila, Ejido el Cedral camino hacia el Valle de Parrenos, J.A. Villarreal Q. 5346, M.A. Carranza P. &A. Rodriguez G. (ANSM); Nuevo Leon: Municipio de Santiago, Canon La Boca, camino a Cola de Caballo-Laguna de Sanchez, M.A. Carranza P. 232, J.A. Villarreal Q. &]. Valdes-Reyna. (ANSM). 17. Muhlenbergia macroura (Kunth) Hitchc., N. Amer. Fl. 17(6):468. 1935. (Fig. 13, A-F). Crypsismacroura Kunth, Nov. Gen. Sp. (quarto ed.) 1:140-141. 1816. Phleum macrourum (Kunth) Willd. ex Steud., Nomencl. Bot. (ed. 2) 1:365. 1840. Epieampes macroura (Kunth) Benth., J. Linn. Soc, Bot. 19:87. 1881. Crypsinna macroura (Kunth) E. Fourn., Mexic. PI. 2:90. 1886. (Fig. X). TYPE: MEXICO. MEXICO: near Nevado de Toluca, Sep, EWH.A. Humboldt & A.].A. Bonpland s.n. (HOLOTYPE: P-BONPL!; ISOTYPE: US-A865654 fragm. ex P-BONPL!). Crypsis setifolia}. Presl, Reliq. Haenk. l(4-5):245. 1830. Cinna setifolia Q. Presl) Kunth, Revis. Gramin. Suppl. xvi. 1830. TYPE: MEXICO. T. Haenke s.n. (HOLOTYPE: PR; ISOTYPE: US-A865655 fragm. ex P-BONPL!). Caespitose perennials. Culms 75-200 cm tall, erect, rounded near base, forming dense clumps of up to 100 culms or more and up to 1 m in diameter, pubescent below the nodes, internodes mostly glabrous. Leaf sheaths 15-40 cm long, shorter than the internodes, glabrous to scaberulous, the basal persistent and keeled with age; ligules (5-)8-40(-50) mm long, strongly decurrent, spliting into broad auricles, membranous to chartaceous above, brownish, firm, the veins evident below and near margins, apex truncate to obtuse; blades 20-60 cm long, 2-5 mm wide, mostly flat and apically involute, scabrous above and below. Panicles (15-)20-40 cm long, 5-12 mm wide, dense, spikelike, erect, exserted and surpassing the blades in height, greenish to greenish-gray; primary branches 0.1-1.2 cm long, ascending and tightly appressed, unexposed, imbricate; pedicels 0.1-1.7 mm long, shorter than the spikelets, scaberulous. Spikelets 3.4-5.6 mm long, erect, strongly laterally compressed, greenish-gray; glumes 3.4-5.6 mm long, linear-elliptic to linear-ovate, usually longer than the lemma, 1-nerved, scabrous along the keel, subequal, unawned, the upper slightly longer, apex acute to acuminate, scabrous; lemmas 3.4-5 mm long, elliptic to linear-elliptic, scabrous, greenish-gray; callus pilose, the hairs 0.1-0.3 mm long, apex acute, rarely mucronate, the mucro less than 0.4 mm long; paleas 3.4-5 mm long, about as long as the lemma, scabrous, apex acute; anthers 1.5-2.2 mm long, dark greenish. Caryopses 2-3 mm long, fusiform, brownish. 2n = 20, 24, 28. Phenology.?Flowering August through December. Distribution and habitat.?Muhlenbergia maeroura occurs in the Sierra Madre Occidental in northern Mexico from Chihuahua to Chiapas, Guatemala, and Costa Rica; found on upland slopes, mountain meadows, in pine or pine-oak forests often in deep humid soils associated with Festuca spp., Piptochaetiumfimbriatum, P. pringlei, Bromus spp., Trisetum spicatum, Pinus spp., Alnus sp., and Quercus greggii; 1500-3400 m. Comments.?Morphologically, M. nigra Hitchc, a species from central and southern Mexico, is dif- ficult to separate from M. macroura. The former, generally has shorter panicles [6-15(-17) cm long], longer glumes [(5.3-)6-8 mm long], longer lemmas (5-6.5 mm long), and narrower leaf blades (2-3 mm wide). Muhlenbergia nigra also tends to be distributed at higher elevations than M. macroura. Specimens examined. MEXICO. Coahuila: ascent to Sierra Infernillo, 15 mi SW of Galeana, C.H. & M.T. Mueller 832 (US); Municipio de Arteaga, Sierra Zapaliname, G.S. Hinton 20506, 20868 (HINT); Municipio de Ramos Arizpe, Sierra de la Paila-Ramoz Arizpe, G. Cano 17 (ENCB); Municipio de Saltillo, Sierra Zapaliname, E of Saltillo at "El Penitente", P.M. Peterson 18797 &]. Valdes-Reyna (ANSM, US). 18. Muhlenbergia microsperma (DC.) Kunth, Revis. Gramin. 1:64. 1829. (Fig. 14, A-D). Prichochloamicrosper- ma DC, Cat. PI. Ftorti Monsp. 151. 1813. Muhlenbergia microsperma (DC.) Trin., Gram. Unifl. Sesquifl. 193. 1824, nom. inval. TYPE: MEXICO, cult, at Montpellier, from seeds collected in Mexico and distributed by the Botanical Garden of Madrid, Sesse &> Mocino s.n. (HOLOTYPE: MPU; ISOTYPES: P!, US fragm. ex P!). Podosemum setosum Kunth, Nov. Gen. Sp. (quarto ed.) 1:129. 1816. Trichochloa setosa (Kunth) Roem. & Schult., Syst. Veg. 2:386. 1817. Agrostis setosa (Kunth) Spreng., Syst. Veg. 1:262. 1825. Muhlenbergia setosa (Kunth) Trin., Gram. Unifl. SesquiE. 193, t. 5, f. 22. 1824. Muhlenbergia setosa (Kunth) Kunth, Revis. Gramin. 1:63. 1829, isonym. TYPE: MEXICO: between Gueguetoque and Tula, Aug, F.W.H.A. Humboldt & A.].A. Bonpland 1171 (HOLOTYPE: P-BONPL!; ISOTYPES: B-W, US-91917 fragm. ex P-BONPL!). Agrostis microsperma Lag., Gen. Sp. PI. 2. 1816. TYPE: MEXICO: plants grown at the Botanical Garden of Madrid from seeds collected by Sesse in Mexico, Sesse s.n.(HOLOTYPE: MA?). Muhlenbergia fasciculata Trin., Gram. Unifl. Sesquifl. 192, 296, t. 5, f. 21. 1824. TYPE: North America, boreali-Amer.(HOLOTYPE: LE?). 968 Journal of the Botanical Research Institute of Texas 1(2) FIG. 13. Muhlenbergia macroura [P.M. Peterson 5970&CR. Annable (US)]. A. Habit. B. Panicle. C. Ligule. D. Glumes. E. Floret. F. Lodicules, stamens, and pistil. Muhlenbergiarigens [J.R. Reeder4589 & C.G. /feeder (ARIZ, US)]. G. Ligule. H. Glumes. I. Floret. J. Lodicules, stamens, and pistil. Peterson et al., Muhlenbergiinae from northeastern Mexico 969 MM FIG. 14. Muhlenbergia mkrosperma [P.M. Peterson 4185 & CR. Annable (ARIZ, ENCB, GH, MEXU, MICH, MO, NMC, NY, RSA, TAES, UC, UNLV, US, UK, WIS, WS)]. A. Habit. B. Llgule. C. Glumes. D. Floret. Muhlenbergiaspiciformis [P.M. Peterson8361 &J. Valdes-Reyna (ANSM, US)]. E. Habit. F. Llgule. G. Glumes. H. Floret. I. Lodkules, stamens, and pistil. 970 Journal of the Botanical Research Institute of Texas 1(2) Muhlenbergia purpurea Nutt., J. Acad. Nat. Sci. Philadelphia, ser. 2, 1:186. 1848. TYPE: U.S.A. CALIFORNIA: Santa Barbara Co.: Santa Barbara and Santa Catalina Island, Gambel s.n. (HOLOTYPE: K!). Muhlenbergia mmosissima Vasey, Bull. TorreyBot. Club 13:231. 1886. TYPE: MEXICO. CHIHUAHUA: SW Chihuahua, Aug-Nov 1885, F. Palmer 158 (LECTOTYPE: NY! designated by Hitchcock, N. Amer. Fl. 27:441. 1935, but without indicating the specilic specimen; Peterson & Annable, Syst. Bot. Monogr. 31:61. 1991 indicated the specific specimen; ISOLECTOTYPES: LE!, MO-2974152!, P!, US-995580!). Caespitose annuals, sometimes appearing as short-lived perennials. Culms 10-80 cm tall, often geniculate at the base, slender, often striate, much branched near the base, scaberulous below the nodes; internodes 1.8-8.6 mm long, mostly scaberulous or smooth. Leaf sheaths 2.2-6.6 mm long, commonly shorter than the internodes, glabrous, smooth or scaberulous; ligules 1-2 mm long, membranous to hyaline, decurrent, margins often extended, apex truncate to obtuse; blades 3-8.5(-10) cm long, 1-2.5 mm wide, flat or loosely involute, scabrous below, strigulose above, often deciduous with age. Panicles 6.5-13.5 cm long, 1-6.5 cm wide, open and not densely flowered, often purplish; primary branches 1.6-4 cm long, ascending or diverging up to 80? from the rachises, spikelet-bearing to the base; pedicels 2-6 mm long, appressed to divaricate, antrorsely scabrous. Cleistogamous panicles with 1-3 spikelets present in the axils of the lower sheaths. Spikelets 2.5-5.5 mm long; glumes 0.4-1.3 mm long, exceeded by the florets, 1-nerved, obtuse, often minutely erose; lower glumes 0.4-1 mm long; upper glumes 0.6-1.3 mm long; lemmas 2.5-3.8(-5.3) mm long, narrowly lanceolate, mostly smooth, scaberulous distally, hairy on the calluses, lower V2 of the margins, and midveins, the hairs 0.2-0.5 mm long, apices acuminate, awned, awns 10-30 mm long, straight to flexuous; paleas 2.2-4.8 mm long, narrowly lanceolate, acuminate; anthers 0.3-1.2 mm long, purplish. Caryopses 1.7-2.5 mm long, fusiform, reddish-brown. In = 20, 40, 60. Phenology.?Flowering March through December. Distribution and habitat.?Muhlenbergia microsperma grows on sandy slopes, drainages, cliffs, rock outcrops, and disturbed roadsides, at elevations of 0-2400 m. It is usually found in creosote scrub with species of Ambrosia, Encelia, Bebbia, Baccharis and Eriogonum, thorn-scrub forest with Acacia and Clethra, sarcocaulescent desert with Acacia, Fouquieria and Bursera, and oak-pinyon woodland associations. Its range extends from the southwestern United States, Mexico in Baja California, Baja California Sur, Sonora, Sinaloa, Chihuahua, Durango, Aguascalientes, Zacatecas, Jalisco, Nayarit, Morelos, Guanajuato, Queretero, Hidalgo, Tlaxcala, Mexico, Michoacan, Guerrero, Oaxaca, Veracruz, and Chiapas, and through Central America and South America along the Andean countries (Espejo Serna et al. 2000; Peterson & Annable 1991). Comments.?Muhlenbergia microsperma can sometimes be confused with M. tenuijolia and differs from it by having cleistogamous panicles in the axils of the lower sheaths and shorter, obtuse glumes, 0.4-1.3 mm (glumes acute to acuminate, 2-2.8 mm long in M. tenuijolia). Specimens examined. MEXICO. Coahuila: Municipio de Arteaga, 17 mi SE of Saltillo & 7.4 mi NE of Jame, P.M. Peterson 10074, C.R. Annable &J. Valdes-Reyna (ANSM, US); 6 km E del entronque carretera 57 hacia los Lirios, J.A. Villarreal Q. 5172,}. Valdes-Reyna, M.E. Barkworth cv P.S. Hoge (ANSM); Municipio de Cuatrocienegas, Ladera baja de la Sierra Cristo, frente al poblado de Cuatrocienegas, A. Rodiiguez-Gdmez 1225, N. Moreno &].]. Lopez G. (ANSM); Municipio de Muzquiz, Rancho San Manuel, J.A. Santos-L. s.n. (ANSM); Sierra La Encantada, 170 km NO de Muzquiz, cuesta de Malena, brecha Muzquiz-Boquillas del Carmen, M.A. Carranza P. 828,]. Valdes-Reyna, P.A. Fryxell, R. VasauezA. cv O. Meza (ANSM); Municipio de Ramos Arizpe, Sierra de la Paila, Ejido el Cedral por el camino El Carmen, J.A. Villarreal Q. 5272, M.A. Carranza P. &A. Rodriguez G. (ANSM); Municipio de Saltillo, 3.5 mi E of Hwy 54 up San Lorenzo Canyon, P.M. Peterson 13259,]. Valdes-Reyna &> M.B. Knowles (US); Canon San Lorenzo en La Sierra Zapaliname, 8 km S de Saltillo, R. Lopez-Aguil- lon s.n. (ANSM, US); Canon San Lorenzo, Canon en la Sierra de Zapaliname, 1.5 km E del pozo numero 2, R. Lopez-Aguillon s.n. (ANSM). Nuevo Leon: Municipio de Allende, 9 mi N of Allende on Mex 85, O.L. Briones 1841 (ENCB); Municipio de Galeana, Ejido 18 de Marzo, J.A. Ochoa-Guillemar 977 (COCA); Municipio de San Carlos, La Begonia, 2 km al S de San Jose, O.L. Briones 1306 (SLPM); Municipio de Santiago, 3 km adelante de la Cienega camino a Laguna de Sanchez, Villa de Santiago, P.A. Garcia-Martinez 1865 (COCA). Tamaulipas: Municipio de Bustamante, Camino a la Joya de San Francisco, A. Brito 121 (COCA); Municipio de Gomez Farias, Rumbo al Rancho La Gloria, M.H. Cervera-Rosado 62 (COCA); Municipio de San Carlos, Cerro del Diente, J.A. Barrientos-B. s.n. (COCA); Municipio de Tula, 32 km al SO de Tula, cerca del limite de estados (San Luis Potosi & Tamaulipas), F. Gonzalez-Medrano 4370, R.M. Lopez F. cv R. Dirzo M. (MEXU); La Tapona, J.F. Iribe-Duarte 156 (COCA); Municipio de Victoria, Carretera Victoria-Tula, J.F. Iribe-Duarte 49 (COCA); km 20 carretera Victoria, San Luis Potosi, G. Villegas-Durdn 265 (COCA). 19. Muhlenbergia minutissima (Steud.) Swallen, Contr. U.S. Natl. Herb. 29(4):207. 1947. (Fig. 6). Agmstis minutissima Steud., Syn. PI. Glumac. 1:171. 1854. Sporobolus minutissimus (Steud.) Hitchc, Proc. Biol. Soc. Wash. 41:161. 1928. TYPE: U.S.A. NEW MEXICO: 1847, A. Fendler 986 (HOLOTYPE: not located; ISOTYPES: MO!, NY-327637!, US-825378!, US-997292!). Peterson et al., Muhlenbergiinae from northeastern Mexico 971 Milium microspermum Lag., Gen. Sp. PI. 2. 1816, non Muhlenbergia mierosperma (DC.) Trin. 1824, Panicum microspermum (Lag.) E. Fourn., Mexic. PL 2:492. 1886. Sporobolus microspermus (Lag.) Hitchc, J. Wash. Acad. Sci. 23(10):453. 1933. TYPE: MEXICO: Habitat in Nova Hispania, D. Sesse s.n. (HOLOTYPE: MA; ISOTYPE: US-91019 fragm.!). Vilja conjusa E. Fourn., Mexic. PL 2:101. 1886. Spomholus conjusus (E. Fourn.) Vasey, Bull. Torrey Bot. Club 15:293. 1888. Muhlenbergia confusa (E. Fourn.) Swallen, Contr. U.S. Natl. Herb. 29(4):207. 1947. TYPE: MEXICO: Jalicingo, C.].W. Schiede & Deppe 913 (SYNTYPES: US-998282 fragm. ex P!, US-3376139Q; Orizaba, Botteii 117 (SYNTYPES: P!, US fragm.!); Orizaba, Schaffner93 (SYNTYPES: P!, US fragm. ex P!); Orizaba, Schajfner 125 (SYNTYPE: P!); Nevado de Toluca, Sep, Hahn s.n. (SYNTYPE: P!); U.S.A., Hall & Harbour 643 (SYNTYPE: P!); Jorullo, in devexis arenosis montis ignivomi, AJ.A. Bonpland in part (SYNTYPE: P?). Delicate annuals. Culms 5-40 cm tall, slender, erect or spreading; scaberulous or strigulose below the nodes; internodes mostly glabrous, scaberulous or smooth. Leaf sheaths 0.4-5.2 cm long, shorter or longer than the internodes, smooth or scaberulous; ligules 1-2.6 mm long, hyaline, margins entire, rarely with lateral lobes or auricles not longer than the body of the ligule, apex truncate to obtuse; blades 0.5-4(-10) cm long, 0.8-2 mm wide, flat or involute, scabrous below, puberulent above, margins and midveins not whitish-thickened. Panicles 5-16.2(-21) cm long, 1.5-6.5 cm wide, open; primary branches 8-42 mm long, often capillary, diverging 25-80? from the rachises; pedicels 2-7 mm long, straight or curved, but rarely curved as much as 90?; glumes 0.5-0.9 mm long, subequal, sparsely strigulose, at least near the apices, the hairs 0.1-0.3 mm long, 1-nerved; lower glumes 0.5-0.8 mm long, obtuse to acute; upper glumes 0.6-0.9 mm long, broader than the lower glumes, obtuse; lemmas 0.8-1.5 mm long, lanceolate, brownish to purplish, glabrous or the midveins and margins appressed-pubescent, apex obtuse to subacute, unawned; paleas 0.8-1.4 mm long, puberulent or glabrous; anthers 0.2-0.7 mm long, purplish. Caryopses 0.6-0.9 mm long, fusiform to elliptic, brownish. In = 60, 80. Phenology.?Flowering July through November. Distribution and habitat.?Muhlenbergia minutissima grows in sandy and gravelly drainages, rocky slopes, flats, road cuts, and open sites. It is usually found in yellow pine and oak-pine forests, pinyon-juniper wood- lands, thorn-scrub forests, and oak-grama savannahs, at elevations of 1200-3000 m; western North America from central Washington to Montana south to Texas, U.S.A., and throughout Mexico to Guatemala. Comments.?The shape and length of the lemmas are variable in this species with some individuals having short (0.8-1.1 mm long), obtuse lemmas and others having longer (1.0-1.5 mm long), subacute lemmas. Muhlenbergia texana Buckley has lemmas similar to the longer-flowered M. minutissima individuals and the lemmas are mucronate or short-awned up to 2 mm long (Peterson & Annable 1991). Currently there are no records of M. texana in NE Mexico. Specimens examined. MEXICO. Tamaulipas: Municipio de Victoria, km 26 carretera Victoria-San Luis Potosi, G. Villegas-Duran 169 (COCA). 20. Muhlenbergia montana (Nutt.) A. S. Hitchc, U.S.D.A. Bull. (1915-23) 772:145, 147. 1920. (Fig. 15, A?C). Calycodon montanum Nutt., Proc. Acad. Nat. Sci. Philadelphia 4:23. 1848. TYPE: U.S.A. NEW MEXICO: Santa Fe Co.: near Santa Fe, W. Gambel s.n. (HOLOTYPE: BM!, ISOTYPES GH, PH). Muhlenbergiagracilis var. enervis Scribn. exBeal, Grass. N. Amer. 2:242. 1896. Muhlenbergia enervis (Scribn. ex Beal) Hitchc, Contr. U.S. Natl. Herb. 17(3):302. 1913. TYPE: MEXICO. CHIHUAHUA: Sierra Madre, dry ledges, 7 Oct 1887, C.C. Piingle 1413 (HOLOTYPE: MSC; ISOTYPES: GH, US-995814!, VT, W-1916-27712!). Muhlenbergia tiijida Hack., Repert. Spec. Nov. Regni Veg. 8:518. 1910. TYPE: MEXICO. MICHOACAN: vicinity of Morelia, Quinceo, 11 Nov 1909, Bro. Arsene 3117 (HOLOTYPE: W-1916-!; ISOTYPES: BM!, MO-843315!, US!, US-86637 fragm!, W-1916-32145!). Densely caespitose perennials. Culms 10-80 cm tall, erect, rounded near base, glabrous below the strictly basal nodes; internodes mostly glabrous, occasionally glaucous. Leaf sheaths 2-35 cm long, longer than the lower internode, glabrous to scaberulous, often glaucous, becoming flattened, loose and papery, and occasionally spirally twisted near base; ligules 4-14(-20) mm long, membranous, decurrent, apex acute to acuminate, often lacerate; blades 6-25 cm long, 1-2.5 mm wide, flat becoming loosely involute to subfili- form, somewhat stiff, scabrous below and hirsute above. Panicles 4-25 cm long, (l-)2-6 cm wide, narrow to somewhat open, loosely-flowered, not dense; primary branches 0.5-10 cm long, ascending, appressed or spreading up to 40? from the rachises; pedicels 0.5-6.5 mm long, flattened, scabrous, occasionally stiffly 972 Journal of the Botanical Research Institute of Texas 1(2) FIG. 15. Muhlenbergia tnontana [P.M. Peterson 8191 & R.M. King (US)]. A. Ligule. B. Floret. C. Glumes. Muhlenbergia setifolia [P.M. Peterson 8368 & J. Valdes-Reyna (ANSM, US)]. D. Habit. E. Ligule. F. Glumes. G. Floret. H. Lodicules, stamens, and pistil. Peterson et al., Muhlenbergiinae from northeastern Mexico 973 reflexed. Spikelets 3-4.5(-7) mm long, erect, occasionally reflexed; glumes (l-)1.5-3.2(-4) mm long, 1/3 to 2/3 as long as the lemma, subequal, glabrous to scaberulous above; lower glumes 1-nerved, sometimes mucronate, the mucro less than 1 mm long; upper glumes 3-nerved, 3-toothed and 3-awned, the teeth (including the awns) 1/3 to V2 the length of the glume, and the awns up to 1.7 mm long, apex truncate to acute; lemmas 3-4.5(-7) mm long, lanceolate, awned, often greenish or yellowish with dark green or purple mottles, scaberulous above, loosely to densely appressed pubescent to pilose along the midvein, margins, and proximal V2 to 4/5, the hairs up to 0.8 mm long, occasionally glabrous, apex acute to acuminate, the awn (2-)6-25 mm long, flexuous; paleas 3-4.5(-7) mm long, lanceolate, loosely to densely appressed pubescent to pilose between the nerves on the proximal 1/3 to 4/5, apex acute to acuminate, scaberulous; anthers 1.5-2.3 mm long, purplish. Caryopses 1.8-2 mm long, fusiform, light brown. In = 20, 40. Phenology.?Flowering July through December. Distribution and habitat.?Muhlenbergia montana ranges from southwestern USA throughout western Mexico to Guatemala, primarily in upland and mountain habitats. In NE Mexico this species is only known from Madera del Carmen and Sierra El Jardin. This species grows on rocky slopes, dry meadows, ridge tops, and open grasslands usually associated with Pinus pseudostrobis, Pinus spp., Arbutus xalapensis, Pseu- dotsuga menziesii, Juniperus deppeana, Cupressus sp., Abies sp., Populus tremuloides, Quercus spp., Ceanothus sp., Cornus stolonijera, Holodiseus discolor, Rhus trilobata, Ribes cereum, Cercocarpus breviflorus, and Festuca arizonica;1400-3500 m. Comments.?Muhlenbergia montana is a highly variable species and is sometimes difficult to separate from the southern Rocky Mountain endemic, M.filiculmis, which has shorter spikelets with shorter lemmatal awns (1-5 mm long), tightly involute and filiform, sharp-tipped blades (2-6 mm long), and shorter culms (5-40 cm tall). The morphological distinctions between these two sister species are not great and further study is warranted. Specimens examined. MEXICO. Coahuila: Madera del Carmen, 3 mi N of El Cinco Junction on road to El Dos, P.M. Peterson 18904 &?]. Valdes-Reyna (ANSM, US); wooded canyon above Campo El Dos, P.M. Peterson 18919 &]. Valdes-Reyna (ANSM, US); Municipio de Acuna, Sierra El Jardin, steep slopes near ridge top, 2410m, P.M. Peterson 19934 & S. Lara-Contreras (US, ANSM). 21. Muhlenbergia polycaulis Scribn., Bull. Torrey Bot. Club 38:327. 1911. (Fig. 10, E-I). TYPE: MEXICO. CHIHUAHUA: Sierra Madre Mountains, 30 Sep 1887, C.C. Pringle 1414 (HOLOTYPE: US-81636!; ISOTYPES: US-822943!, US-155173!, US-995733!). Loosely caespitose perennials from a firm, knotty, short rhizomatous base. Culms 15-40(-50) cm tall, erect, decumbent at base, often geniculate, strigulose below the nodes; internodes strigulose to glabrous. Leaf sheaths 1-8 cm long, mostly shorter than the internodes, glabrous to scaberulous, without necrotic spots and not becoming spirally coiled when old; ligules 0.5-2.5 mm long, erose or lacerate, apex obtuse to acute, margins hyaline, firmer than the central portion; blades 3-10 mm long, 0.5-2 mm wide, flat or involute, occasionally folded, hirsute or scaberulous above and scaberulous or smooth below. Panicles 2-12 cm long, (0.6-)l-2 cm wide, narrow, contracted and interrupted below; panicle branches 0.5-4 cm long, ascending and appressed occasionally spreading up to 30? from the rachises, spikelet bearing to the base; pedicels 0.1-1.5 mm long, scabrous. Spikelets 2-3.5 mm long, plump near the middle; glumes (l-)1.5-2.6 mm long, more than V2 as long as the lemma, subequal, 1-nerved, mucronate, awned or unawned, scabrous along midvein near apex, apex acute sometimes acuminate, the awn up to 1.4 mm long; lemmas 2-3.5 mm long, elliptic, widest near the middle, appressed-pubescent along the midvein and margins on the proximal V2 to 2/3, the hairs up to 0.5 mm long; apex acuminate, scaberulous, awned, the awn 10-20(-25) mm long, flexuous; paleas 2-3.5 mm long, elliptic, appressed pubescent between the nerves on the proximal V2, apex acuminate; anthers 1.5-2 mm long, orange. Caryopses 1.5-2 mm long, fusiform, brownish. 2n = 20, 40. Phenology.?Flowering August through October. Distribution and habitat.?Steep rocky slopes, canyon walls, cliffs, table rocks, and volcanic rock out- crops in open vegetation associated with Quercus spp., Pinus spp., P. cembroides, P. chihuahuana, Pseudostuga menziesii, Cupressus sp., Abies sp., Ceanothus sp., Juniperus deppeana, Arctostaphylos sp., A. pungens, Cercocar- 974 Journal of the Botanical Research Institute of Texas 1(2) pus sp., Rhus trilobata, Brickellia sp., Agave sp., Tillandsia sp., Platanus wrightii, Fouquieria splendens, Cornus stolonijera, Polypodium sp., and Selaginella sp.; 1200-2410 m; southeastern Arizona, southern New Mexico, southwestern Texas, U.S.A. to northern Mexico in Baja California, Baja California Sur, Sonora, Sinaloa, Chihuahua, Durango, Zacatecas, Aguascalientes, San Luis Potosi, Guanajuato, Hidalgo, Jalisco, Mexico, Nayarit, and Queretaro (Espejo Serna 2000; Herrera Arrieta 2001; Peterson 2003). Specimens examined. MEXICO. Coahuila: Sierra del Carmen, Ejido San Francisco, Ryolytic rock outcrop W of cabin headquarters, P.M. Peterson 18845,]. Valdes-Reyna & C. Sifuentes (ANSM, US); Madera del Carmen, 10 mi NW of Mares, P.M. Peterson 18883 &]. Val- des-Reyna (ANSM, US); Madera del Carmen, Wooded canyon above Campo El Dos, P.M. Peterson 18914 &]. Valdes-Reyna (ANSM, US); Municipio de Acuna, W slope of Sierra El Jardin, E of Rancho El Caballo, M.C. Johnston 9292, F. Chiang C. & T.L. Wendt (ANSM); Sierra El Jardin, steep slopes near ridgetop, 2410m, P.M. Peterson 19937 &> S. Lara-Contreras (US, ANSM); Municipio de Muzquiz, Rancho La Encantada, ].A. Santos L. 250F (TAES); Municipio de Saltillo, Rancho Demostrativo "Los Angeles" 48 km S of Saltillo, S.L. Hatch 4548, C.W. Morden &?]. Valdes-Reyna (TAES). 22. Muhlenbergia porteri Scribn. exBeal, Grass. N. Amer. 2:259. 1896. (Fig. 16, A-E). MuhlenbergiatexanaThurb. ex Porter &J.M. Coult., Syn. Fl. Colorado 144. 1874. nom. illeg., non Muhlenbergia texana Buckley Podosemum ported (Scribn. ex Beal) Bush, Amer. Midi. Naturalist 7(2):36. 1921. TYPE: U.S.A. TEXAS: Rio San Pedro, 5 Nov 1850, ].M. Bigelow s.n. (SYNTYPES: GH, US fragm. ex GH!); Presidio del Norte, Jul 1852, C.C. Party s.n. (SYNTYPES: GH, US fragm. ex GH!); Western Texas to El Paso, May-Oct 1849, C. Wright 734 (SYNTYPES: GH, MO!, US fragm. ex GH!). Loosely caespitose perennials with a wirey and knotty base, rhizomes absent, distinctly bushy in appearance. Culms 25-100 cm long, 0.5-1.5 mm think, erect, geniculate and widely spreading near base, freely branched, branching at the lower and middle nodes; scaberulous below the nodes; internodes mostly scaberulous. Leaf sheaths 0.7-4 cm long, shorter than the internodes, glabrous; ligules l-2.5(-4) mm long, toothed or lacerate, apex truncate, margins hyaline, decurrent, sometimes extended to form short auricles; blades 2-8 cm long, 0.5-2 mm wide, flat or folded, scaberulous above and smooth to scaberulous below. Panicles 4-14 cm long, 6-15 cm wide, open, loosely flowered, usually purple, panicle branches 1-7.5 cm long, widely divergent and stiffly spreading 30-90? from the rachises, not floriferous basally; pedicels 2-13(-20) mm long, scabrous. Spikelets 3-4.5 mm long, often purple; glumes 2-3 mm long, subequal, 1-nerved, occasionally mucronate, scabrous along the nerve, apex acuminate, occasionally mucronate, the mucro up to 0.4 mm long; lemmas 3-4.5 mm long, lanceolate, purplish, appressed-pubescent on the margins and midvein on the proximal Vi to 3A, apex acuminate, awned, the awn 5-13 mm long, straight; paleas 3-4.5 mm long, lanceolate, glabrous or appressed-pubescent between the nerves on the proximal 4/5, apex acuminate; anthers 1.5-2.3 mm long, purple to yellow. Caryopses 2-2.4 mm long, ellipsoid, compressed, yellowish brown. 2n = 20, 23, 24, 40. Phenology.?Flowering June through October. Distribution and habitat.?Rocky slopes among boulders, dry arroyos, desert flats and grasslands, and cliffs, frequently in protection of shrubs associated with Prosopis sp.,Larrea tridentata, Dasylirion longissimum, Agave lecheguilla, Jatwpha dioiea, Opuntia sp., Acacia spp., Yucca sp., Psilostrophe sp., Mimosa sp., Nolina sp., Bouteloua spp., and Eragwstis spp.; 600-1700 m; southeastern California, southern Nevada, southern Utah, Arizona, southern New Mexico, western Texas, and scattered in western Oklahoma and Colorado to Mexico in Baja California, Sonora, Chihuahua, Durango, Zacatecas, and San Luis Potosi. Comments.?This grass is highly palatable to all classes of livestock but is never abundant at any par- ticular site to provide a significant source of forage. Specimens examined. MEXICO. Coahuila: 16.9 km NE of San Miguel on road towards Boquillas, P.M. Peterson 10609 &> C.R. Annable (US); 7.2 mi SEW of Jaboncillos on road towards Cuesta de Malena, P.M. Peterson 19846 & S. Lara-Contreras (ANSM, US); Municipio de Cuatrocienegas, Cuatrocienegas, A. Miranda 7-a (COCA); Ladera baja de la Sierra Cristo, frente al poblado de Cuatrocienegas, A. Rodriguez-Gdmez 1224, N. Moreno &>].]. Lopez G. (ANSM); Laderas de la Sierra de San Marcos 24 mi SWof Cuatrocienegas, P.M. Peterson 10010, C.R. Annable &]. Valdes-Reyna (ANSM, US); Sierra de San Marcos, areas cercanas a la Poza de La Becerra, A. Zarate-Lupercio 5 (ANSM); Municipio de General Cepeda, 41 mi W of Saltillo, F.W. Gould 11535 (TAES); Municipio de Lampazos de Naranjo, Rancho Las Rusias, S. Gonzalez s.n.(TAES); Municipio de Muzquiz, El Sauz, entronque carretera 57, 32 km S de Sabinas, R. Vdsquez-Aldape 218 (ANSM); Municipio de Ocampo, Rancho el Barranquito, 50 km de Ocampo rumbo a Sierra Mojada, M.A. Carranza P. 575 & F.J. Carranza P. (ANSM); Sierrra La Encantada, Rancho Puerto de Aire, R. Vdsquez-Aldape 238 (ANSM, CIIDIR); Municipio de Ramos Arizpe, Sierra de la Paila (Lado Norte), Canada Becerros,].A. Villarreal Q. 5446, M.A. Carranza P. & L. Arce G. (ANSM); Municipio de Saltillo, 15 Mi W of Peterson et al., Muhlenbergiinae from northeastern Mexico 975 Fie. 16. Muhlenbergiaporteri [P.M. Peterson 8144 & R.M. King (ANSM, US)]. A. Habit. B. Ligule. C. Glumes. D. Floret. E. Lodkules, stamens, and pistil. Muhlenbergia villiflora var. villiflora [P.M. Peterson 10982, C.R. Annable & J. Valdes-Reyna (ANSM, US)]. F. Ligule. G. Glumes. H. Lemma. I. Lodicules, stamens, and pistil. 976 Journal of the Botanical Research Institute of Texas 1(2) Saltillo along highway 40 to Torreon, S.L. Hatch 5052 &]. Valdes-Reyna (ANSM, TAES); Carretera Saltillo-Torreon km 33,].F. Cano-Sdler 127 (ANSM); Municipio de Torreon, Torreon and vicinity, E. Palmer 511 (TAES); Sierra dejumilco, proximidadesalejido La Trinidad, ].A. Villarreal 1116 (CIIDIR); Municipio de Sierra Mojada, 35 km al SE de Jaco, R. Aguirre C. (INEGI). Nuevo Leon: 9.4 mi Wof San Antonia de Peha Nevada & 0.4 mi E of Jtn of Hwy 2 to Dr. Arroyo, P.M. Peterson 16793, J. Valdes-Reyna & M. Sosa Morales (ANSM, US). Tamaulipas: Municipio de Miquihuana, 4 Km al O del Tanque de Eguia, hacia la Presa de San Carlos, F. Gonzdlez-Medrano 9029 (MEXU). 23. Muhlenbergia pubigluma Swallen, Proc. Biol. Soc. Wash. 56:78. 1943. (Fig. 17, A-D). TYPE: MEXICO. COAHUILA: Municipio de Cuatro Cienegas, Sierra de la Madera, Canon del Agua, 10 Sep 1939, CH. Mailer 3261 (HOLOTYPE: US-2209360!). Densely caespitose perennials. Culms (50-)65-125 cm tall, stout, erect, puberulent below the nodes, 2 or 3 nodes per culm; internodes glabrous. Leaf sheaths 10-32 cm long, usually longer than the internodes, scaberulous, basal sheaths compressed-keeled, glabrous, dark-brown with age; ligules 5-13 mm long, membranous above and firm and brown below, decurrent; blades 10-35 cm long, 1.5-3 mm wide, folded to involute, attenuate, firm, scabrous with whitish pubescent, the short hairs about 0.1 mm long, these slightly longer on the upper surface and near the collar. Panicles (15-)20-34 cm long, 1-3 cm wide, narrow, loosely contracted; primary branches 1-6 cm long, mostly ascending and appressed, rarely spreading up to 20? from the rachises, grayish-green; pedicels 0.3-2.5 mm long, usually shorter than the spikelets, scabrous. Spike- lets 2.5-3.5 mm long; glumes 2-3.3 mm long, usually shorter than the floret, 1-nerved, lightly pubescent especially near base, apex obtuse to acute, unawned; lemmas 2.8-3.5 mm long, lanceolate, grayish-green to purplish, the lateral nerves indistinct, appressed villous on lower Vi, basal margins densely villous, the hairs less than about 0.5 mm long, apex acute, usually short-awned, the awns 0.5-3.5 mm long; paleas 2.7-3 mm long, pubescent between the nerves on the proximal 1/3, apex obtuse; anthers 1.4?1.6 mm long, yellowish. Caryopses not seen. Phenology.?Flowering September through November. Distribution and habitat.?Muhlenbergia pubigluma primarily occurs on calcareous slopes and flats with Bouteloua, Aristida, Quercus, Rhus virescens, Pinus eembroides, Pinus spp., Pseudotsuga menziesii, Agave leeheguilla, Abies, Holodiscus, and Populus tremuloides; 1800-3400 m. Comments.?Muhlenbergia pubigluma is morphologically very similar to Muhlenbergia pubescens (Kunth) Hitchc, a species common in the Sierra Madre of western Mexico. Individuals of M. pubigluma have broadly decurrent ligules 5-13 mm long that are firm and brown at the base, whereas ligules of M. pubescens are only 1.5-6 mm long and are not decurrent or firm and brown near the base. In general, the culms, leaves, glumes, lemmas, and paleas of M. pubescens are villous with wavy hairs 0.2-1 mm long. In M. pubigluma, these same structures are pubescent with straight hairs usually less than 0.2 mm long. However, there are four collections of M. pubigluma: Peterson 6251, 10068 & Amiable; Peterson 8385, Valdes-Reyna & Villarreal G.; Peterson 13355 &> Knowles, that have longer hairs on the glumes, lemmas, and paleas that resemble individu- als of M. pubescens. Specimens examined. MEXICO. Coahuila: 4 km E of Los Lirios on road to Laguna de Sanchez, 50 km SE of Saltillo, P.M. Peterson 6251 &C.R. Annable (US); 12.9 km E of Los Lirios on road to Laguna de Sanchez, 60 km SE of Saltillo, P.M. Peterson 6258 & C.R. Annable (US); Municipio de Arteaga, SE of San Antonio de las Alazanas and SE of Saltillo along road up Coahuilon, P.M. Peterson 8385.]. Valdes-Reyna ??].A. Villarreal G. (ANSM, US); 41.4 km SE of Saltillo and 4.3 km SE of Jame on road to Sierra La Viga, P.M. Peterson 10068, C.R. Annable &?]. Valdes-ReynaQJS); 26.7 mi SE of Saltillo & 2.7 mi SE of Jame, on road towards Sierra La Viga, 2640 m, P.M. Peterson 10058, C.R. An- nable &?}. Valdes-Reyna (ANSM, US); 5 mi W of Chapultepec on cutoff road between Hwy 54 Sr 57, 23 mi S of Saltillo, P.M. Peterson 13279 & M.B. Knowles (US); Sierra de Arteaga, El Tunal, carretera estatal 65, P.S. Hoge 280, M.E. Barkworth &]. Valdes R. (ANSM); Municipio de Ocampo, Crest of the range, at top of S-facing scarp, near Canon del Desiderio, J. Valdes-Reyna 1071 & T.L. Wendt (ANSM); Municipio de Saltillo, Canada Salsipuedes, en la Sierra Zapaliname, 3 km NO de Cuahtemoc, R. Lopez-Aguillon s.n. (ANSM); Sierra Zapaliname, 1 km S del Canon de San Lorenzo, R. Lopez-Aguillon s.n. (ANSM); Sierra Zapaliname, ca. 5 km east of Saltillo (Las Palapas) up Camino de Quatro, P.M. Peterson 17864, 17867,]. Valdes-Reyna & R.H. Cardenas (ANSM, US); 18 mi S of Saltillo on Mexico 54 and 1.3 mi W on road to microondas, just W of Estacion Carneros, P.M. Peterson 8118 8120, 8121 & M.A. Carranza P. (ANSM, US); 30.6 km SE of Saltillo on hwy 57 to San Luis Potosi, P.M. Peterson 6211 &> C.R. Annable (US); 15 mi S of Saltillo on Mexico 54 and 10 mi E to Rancho Experimental Los Angeles, P.M. Peterson 8126, 8127 & M.A. Carranza P. (ANSM, US); 3.5 mi E of Hwy 54 up San Lorenzo Canyon, P.M. Peterson 13262, J. Valdes-Reyna cy M.B. Knowles (US). Nuevo Leon: 6.7 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13329 & M.B. Knowles (ANSM, US)10.4 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13355 & M.B. Knowles (ANSM, US); Peterson et al., Muhlenbergiinae from northeastern Mexico 977 FIG. 17. Muhlenbergiapubigluma [P.M. Peterson 8426 & M.A. Cairanza P. (ANSM, US)]. A. Ligule. B. Glumes. C. Floret. D. Lodicules, stamens, and pistil. Muhlenbergiarobusta [P.M. Peterson 6131&C.R. Annable (US)]. E. Habit. F. Panicle. G. Ligule. D. Glumes. I. Floret. J. Lodicules, stamens, and pistil. 978 Journal of the Botanical Research Institute of Texas 1(2) Municipio de Galeana, 12 km E of highway 57 on hwy 58, C.W. Morden 519 (ANSM, TAES); San Pablo to San Pedro Sotolar, G.S. Hinton 27299 (HINT): Municipio de General Zaragoza, 9 km S of Aramberri on road towards Zaragoza, P.M. Peterson 15838 &]. Valdes-Reyna (ANSM, US); Zaragoza, G.S. Hinton 23654 (ANSM, HINT); above El Barro, G.S. Hinton 27980 (HINT); Municipio de General Zaragoza, W of Zaragoza, G.S. Hinton 23654 (HINT); 9 km S of Aramberri on road towards Zaragoza, P.M. Peterson 15838 &]. Valdes-Reyna (ANSM, US); Municipio de Santiago, Santiago, I. Cabral-Cordero 609 (ANSM). 24. Muhlenbergia purpusii Mez, Repert. Spec. Nov. Regni Veg. 17(13-18):214. 1921. (Fig. 11, G-L). TYPE: MEXICO. SAN LUIS POTOSI: Minas de San Rafael, Nov 1911, C.A. Purpus 5011 (HOLOTYPE: B; ISOTYPES: MO-2974180!, US-463679!, US-72636 fragm. ex BQ. Caespitose perennials. Culms 25-60 cm tall, erect, pubescent below the nodes, the nodes all basal terete, usually 1 node per culm; internodes scabrous and pubescent. Leaf sheaths 1-20 cm long, shorter than the internodes, pubescent to hispidulous, sheaths rounded, brownish with age below; ligules 4-10 mm long, membranous above and firm and brownish below, decurrent, margins puberulent and wider than Vi the adjacent blade width, apex acuminate; blades 5-13 cm long, 0.7-1.8 mm wide, flat or folded, falcate, pu- berulent to hispidulous above and below, the hairs about 0.1 mm long, margins scabrous. Panicles 7-25(-30) cm long, 1-10 cm wide, loosely contracted to open, ovate to pyramidal, purplish; primary branches 2-8.5 cm long, capillary, ascending, appressed or spreading up to 50? from the rachises; pedicels (2-)4-14 mm long, mostly longer than the spikelets, flexuous, glabrous and smooth. Spikelets 2.4-3.2 mm long, purplish; glumes 0.7-1.1 mm long, less than Vi as long as the lemma, obscurely 1-nerved, puberulent on upper 2/3, apex obtuse to acute often erose; lemmas 2.3-3.1 mm long, lanceolate, purplish, short pilose, the hairs 0.1-0.2 mm long, callus short pilose, apex acute, entire to minutely bifid, awned, the awn 10-20 mm long, flexuous; paleas 2.4-3.2 mm long, slightly longer than the lemma, short pilose between the nerves, apex acute; anthers 1.6-2 mm long, purplish. Caryopses 1?1.2 mm long, fusiform to ovoid, brownish. In = 20. Phenology.?Flowering September through November. Distribution and habitat.?Muhlenbergia purpusii occurs on calcareous derived soils primarily on gypsum flats usually on the sides of sink holes, rock outcrops, roadsides, and slopes with Muhlenbergia gypsophila, Pinus cembroides, Leueophyllum hintonii, Agave leeheguillaa, Juniperusflaccida, Gutierrezia microphylla, Bouteloua chasei, and Yucca filijera; 1240-1900 m. This species has also been reported in Chihuahua, Coahuila, and San Luis Potosi (Espejo Serna et al. 2000; Davila et al. 2006). Specimens examined. MEXICO. Nuevo Leon: 7.5 km E of Puentes on dirt road, P.M. Peterson 17847, J. Valdes-Reyna dv G.S. Hinton (ANSM, US). Tamaulipas: 101.6 km SW of Ciudad Victoria on MEX 101 towards San Luis Potosi, P.M. Peterson 8325 & R.M. King (ANSM, US); Municipio de Jaumave,19 km al S de Avila y Urbina, F. Gonzdlez-Medrano H248, P. Hiriart, V. Judrez, R. Molczadzhi & L. Hernandez (MEXU). 25. Muhlenbergia quadridentata (Kunth) Trim, Gram. Unifl. Sesquifl. 194, t. 5b, f. 14. 1824. (Fig. 18, A?D). Podosemum quadndentatum Kunth, Nov. Gen. Sp. (quarto ed.) 1:130?131. 1816. Muhlenbergia quadndentata (Kunth) Kunth, Revis. Gramin. 1:64. 1829, isonym. Trichochloa quadridentata (Kunth) Roem. &Schult., Syst. Veg. 2:388. 1817. Muhlenbergia virescens subsp. quadridentata (Kunth) Y. Herrera, Amer. J. Bot. 81(8):1043. 1994. TYPE: MEXICO. MEXICO: near Toluca, Sep, EW.H.A Humboldt &A.J.A. Bonplands.n. (LECTOTYPE: P-BONPL!, designated by McVaugh 253. 1983; ISOLECTOTYPE: GH, US-2557456!, US-86634 fragm. exP!,US-86635!)- Podosemumgracile Kunth, Nov. Gen. Sp. (quarto ed.) 1:131?132. 1816. Muhlenbergia gracilis (Kunth) Trim, Gram. Unifl. Sesquifl. 193, t. 5a, f. 6. 1824. Muhlenbergia gracilis (Kunth) Kunth, Revis. Gramin. 1:64. 1829, isonym. TYPE: MEXICO. MICHOACAN: Volcan de Jorullo, Sep, EW.H.A. Humboldt & A.].A. Bonpland s.n. (HOLOTYPE: P-BONPL!; ISOTYPES: LE-TRIN-1501.02!, US-86636 fragm. ex P-BONPL!). Caespitose perennials with short, stout rhizomes. Culms 20-70 cm tall, erect, mostly glabrous below the nodes, the nodes basal, flattened, 1 node per culm; internodes mostly scabrous. Leaf sheaths 10-30 cm long, shorter than the internodes, scabrous to smooth; basal sheaths densely pubescent to glabrous abaxially, smooth and shiny adaxially, becoming flattened and usually not spirally twisted with age; ligules 2-8 mm long, membranous to hyaline above, firm and often brownish with evident veins near the margins below, decurrent, apex acuminate often lacerate; blades 5-15 cm long, 0.6-2 mm wide, flat or usually tightly involute, scaberulous below, short-spiculate and often villous above, the hairs 0.2-0.5 mm long, usually Peterson et al., Muhlenbergiinae from northeastern Mexico 979 1mm 1mm Gr?oberts FIG. 18. Muhlenbergia quadridentata [J.H. Beamon2472 (MICH, US)]. A. Habit. B. Ligule. C. Glumes. D. Floret. Muhlenbergia virescens [P.M. Peterson 6201 & C.R. Atmable (US)]. E. Ligule. F. Portion of panicle branch. G. Glumes. H. Floret. 980 Journal of the Botanical Research Institute of Texas 1(2) appressed, the spicules shiny to whitish. Panicles 5-20 cm long, 0.5-2 cm wide, narrow, loosely-contracted, interrupted below, mostly plumbeous; primary branches 0.5?5(?6) cm long, appressed and ascending to spreading up to 30? from the rachises; central axis flattened with 2 ribs, scabrous; pedicels 0.5-2 mm long, shorter than the spikelets, scabrous. Spikelets 3.4-4.7 mm long, mostly plumbeous; glumes 1.8-4 mm long, shorter to almost as long as the floret, unequal, mostly greenish-plumbeous, scabrous, usually with a few short hairs below; lower glumes 1.8?2.5(?3) mm long, 1-nerved, apex obtuse to acute, often with 2 small teeth; upper glumes (3-)3.2-4 mm long, 3-nerved, apex truncate, obtuse or acute, often with 3 or 4 small teeth, the teeth less than 1/6 the length of the glumes; lemmas 3-4.7 mm long, lanceolate, terete, usually awned, greenish-plumbeous to mottled-plumbeous, sparsely pilose near base and margins on lower V2, apex acuminate, scabrous, the awn 0-20 mm long, flexuous, scabrous, greenish-plumbeous; paleas 2.8-4.3 mm long, shorter than the lemma, pilose on the proximal V2; anthers 1-2.5 mm long, purple. Caryopses 1.8-2 mm long, fusiform, brownish. In = 20. Phenology.?Flowering July through November. Distribution and habitat.?Muhlenbergia quadridentata occurs on open to forested slopes derived from calcareous and volcanic rocks, and is associated with Pinus spp., P. culminicola, Abies sp., Holodiscus discolor, Populus tremuloides, Pseudostuga menziesii, and Quercus spp.; (1900-)2500-4100 m; throughout Mexico in the higher mountains and found in Guatemala. Comments.?The distinction between M. quadridentata and M. virescens is minimal and it is quite pos- sible that they represent different morphological forms corresponding to their distinctive habitat preferences (McVaugh 1983). Generally the greenish-plumbeous spikeleted forms (M. quadridentata) are found above 2500 m whereas the whitish-hyaline to grayish-green forms (M. virescens) are found between 1600-2700 m. Even this color distinction can break down since intermediate individuals are not uncommon. Reeder (1995) mentioned that in M. quadridentata the ligule is shorter, firmer near the base, and frequently with vascular traces, and the blades are strongly ribbed with tiny spicules on the ribs. After studying the types, including that of M. curvula, we find these same characteristics in many specimens of M. virescens as anno- tated by C.G. Reeder. One character that seems to be fairly consistent within each species is the presence of hairs at the base of the glumes (Reeder 1995). In addition to having dull, scabrous glumes, most individu- als of Muhlenbergia quadridentata have a few short hairs near the base, whereas individuals of M. virescens have whitish or stramineous glumes that are glabrous and shiny near the base. The panicles of M. virescens are often wider (0.5-5 cm) with branches spreading up to 45? from the rachises. Muhlenbergia montana, a common and widespread species known only in NE Mexico from Madera del Carmen and Sierra El Jardin, is morphologically similar to M. quadridentata and M. virescens. However, M. montana differs primarily by having upper glumes that are 3-awned (McVaugh 1983). Even though there has been a recent revision of the Muhlenbergia montana complex (Herrera Arrieta 1998) a more thorough study of this group is needed since species limits have not been tested. Specimens examined. MEXICO. Coahuila: Municipio de Arteaga, Sierra La Viga 6 km al E de Jame Puerto de Maravillas, J.A. Villar- real VR-1987 (MEXU); 51.6 km SE of Saltillo and 13 km SE of Jame on road to Sierra La Viga, P.M. Peterson 10056, 10057, C.R. Amiable &?]. Valdes-Reyna (US); 55.3 km SE of Saltillo and 16.6 km SE of Jame on road to Sierra La Viga, P.M. Peterson 10062, C.R. Annable &]. Valdes-Reyna (US); Sierra La Viga 6 km al E de Jame, Puerto Maravillas, J.A. Villarreal Q. 1987, J. Valdes-Reyna, P.S. Hoge & M.E. Barhworth (ANSM, MEXU, US); Sierra La Viga, J.A. McDonaldllOO (MEXU, TEX); A. Moreno T. 1192 (INEGI), C.E. Zermeno B. 1155 (INEGI); Cima de Sierra La Marta en la ceja de la ladera sur, J.A. McDonald 1235 (COCA). Nuevo Leon: 12.7 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13340 & M.B. Knowles (US). 26. Muhlenbergia racemosa (Michx.) Britton, Sterns & Poggenb., Prelim. Cat. 67. 1888. (Fig. 19, A-E). Agrostis racemosa Michx., Fl. Bor.-Amer. 1:53. 1803. Vilfa racemosa (Michx.) P. Beauv., Ess. Agrostogr. 16, 148, 182. 1812. Polypogon racemosus (Michx.) Nutt, Gen. N. Amer. PL 1:51. 1818. Cinna racemosa (Michx.) Kunth, Revis. Gramin. 1:67. 1829. TYPE: U.S.A. ILLINOIS: in ripis sabulosis inundatis fluminis Mississippi, Michaux s.n. (HOLOTYPE: P!; ISOTYPE: US-76287 fragm. <5r photo ex P!). Muhlenbergia glomeratavar. ramostf Vasey, Descr. Cat. Grass. U.S. 40. 1885. Muhlenbergia racemosa var. ramosa (Vasey) Vasey ex Beal, Grass. N. Amer. 2:253. 1896. TYPE: U.S.A. DAKOTA-WISCONSIN: 188?, G.R. Vasey s.n. (LECTOTYPE: US-994606!, here designated, Hitchcock designated a specimen "type from Dakota and Wisconsin" in N. Amer. Fl. 17(6):453. 1935, but did not specify an herbarium). Peterson et al., Muhlenbergiinae from northeastern Mexico 981 FIG. 19. Muhlenbergiaracemosa [I. Valdes-Reyna 1277&D. Riskind (ANSM, US)]. A. Habit. B. Ligule. C. Glumes. D. Floret. E. Lodicules, stamens, and pistil. Muhlenbergia wrightii [Stanford2672, Lauber& Taylor (US)]. F. Habit. G. Ligule. H. Glumes. I. Floret. J. Lodicules, stamens, and pistil. 982 Journal of the Botanical Research Institute of Texas 1(2) Perennials with slender, elongate, scaly rhizomes. Culms 30-110 cm tall, stiffly erect, in clumps, branched above from the middle, glabrous to puberulent below the nodes; internodes smooth and polished, glabrous. Leaf sheaths 1.5-7.5 cm long, slightly keeled, scaberulous; ligules 0.6?1.5(?1.7) mm long, membranous, lacerate-ciliolate, apex truncate; blades 2-17 cm long, 2-5 mm wide, flat, scabrous, scaberulous, or occa- sionally smooth. Panicles 0.8-16 cm long, 0.3-1.8 cm wide, narrow, densely-flowered, condensed, lobed; primary branches 0.2-2.5 cm long, ascending and appressed; pedicels 0-1 mm long, shorter than the spikelets, erect, strigose. Spikelets 3-8 mm long; glumes 3-8 mm long including the awns, 1.3-2 times longer than the lemma, subequal, awn-pointed, 1-nerved, smooth to scaberulous near apex, apex acumi- nate, the awn up to 5 mm long; lemmas 2.2-3.8 mm long, lanceolate, unawned or mucronate, short pilose along the midvein and margins on the proximal Vi, callus short pilose, apex acuminate, scaberulous, the mucro up to 1 mm long; paleas 2.2-3.8(-4.5) mm long, lanceolate, loosely pilose between the nerves on the proximal Vi, apex acuminate; anthers 0.4-0.8 mm long, yellowish. Caryopses (1.2?)1.4?2.3 mm long, fusiform, brown, n = 20. Phenology.?Flowering August through October. Distribution and habitat.?Muhlenbergia racemosa is found on rocky slopes, irrigation ditches, season- ally wet meadows, margins of cultivated fields, railways and roadsides, prairies, sandstone outcrops, stream banks, and along forest ecotones; 30-3400 m. This species is more common in northcentral United States but ranges from southern Canada sporadically throughout the western U.S.A. to Coahuila, Mexico. Specimens examined. MEXICO. Coahuila: Municipio de Acuha, Serranias del Burro, Rancho El Bonito, 12 km N ol headquarters, J. Valdes-Reyna 1227 & DM. Rishind (ANSM); Serranias del Burro, Rancho El Bonito, Canon Los Ojitos, J. Valdes-Reyna 1248 & D.H. Riskind (ANSM). 27. Muhlenbergia repens (J. Presl) Hitchc, Fl. Calif. 1:111. 1912. (Fig. 20, A-D). Sporobdus repens}. Presl, Reliq. Haenk. 1(4-5):241. 1830. Vilja repens (J- Presl) Trin., Mem. Acad. Imp. Sci. Saint-Petersbourg, Ser. 6, Sci. Math., Seconde Pt. Sci Nat. 6,4(1-2):102. 1840. TYPE: MEXICO. Haenke s.n. (HOLOTYPE: PR; ISOTYPES: LE-TRIN-1732.01!, MO fragm. Sr fig!, US fragm!). Muhlenbergia subtilis Nees, Linnaea 19(6):689. 1847. TYPE: MEXICO. Aschenbotn 206 (HOLOTYPE: B; ISOTYPE: US fragm. ex B!). Muhlenbergia abata I.M. Johnst., J. Arnold Arbor. 24:387-388. 1943. TYPE: U.S.A. NEW MEXICO: Valley of the Rio Grande, 1851-1852, C. Wiight 1982 (HOLOTYPE: GH; ISOTYPE: US-556896!)- Perennial with shining, creeping, scaly rhizomes. Culms 5-42 cm tall, decumbent near base, forming dense mats, freely branching above, glabrous below the nodes; internodes mostly glabrous below, lightly nodulose roughened just below the inflorescence. Leaf sheaths 0.6-3.4 cm long, shorter or longer than the internodes, glabrous, margins hyaline; ligules 0.1?1(?1.8) mm long, membranous, decurrent, apex truncate, occasionally lacerate; blades 0.4-6 cm long, 0.5-1.4 mm wide, involute, somewhat arcuate-spreading, mostly glabrous below and scaberulous above. Panicles 1-9 cm long, 0.1-0.6 cm wide, narrow, contracted, loosely-flow- ered, usually included at the base in the uppermost leaf sheath; primary branches 0.2-3 cm long, usually closely appressed, rarely diverging up to 40? from the rachises; pedicels 0.2-3.6 mm long, minutely setose. Spikelets 2.6-4.2 mm long, occasionally 2-flowered; glumes 1.1-3.6 mm long, V2 to as long as the lemma, subequal, usually 1-nerved, occasionally 2- or 3-nerved, light green, apex acute; lemmas 2.6-3.2(-4.2) mm long, lanceolate, unawned or mucronate, dark greenish or mottled, glabrous or with minute appressed pubescence along the margin and base, the hairs less than 0.1 mm long, apex acute to attenuate and taper- ing, scaberulous, the mucro 0.1-0.8 mm long; paleas 2.1-3.3 mm long, lanceolate, glabrous to scaberulous, apex acute; anthers 0.7-1.4 mm long, yellow to purplish. Caryopses 1.1-1.5 mm long, ellipsoid to ovoid, brownish. In = 60, 70-72. Phenology.?Flowering May through November. Distribution and habitat.?Muhlenbergia repens occurs on sandy meadows, canyon bottoms, calcareous rocky flats, gypsum flats, rolling slopes, and roadsides associated with Pinus spp., P. cembroides, P.johannis, Pseudotsuga menziesii, Cupressus sp., Abies sp., Quercus spp., Juniperus deppeana, Cornus stolonijera, Chryso- thamnus nauseosus, Arctostaphylos spp., Prosopis spp., Larrea tridentate, Cereocarpus ledijolius,, Flaveria spp., Ceanothus spp., Fallugia paradoxa, Dasylirion sp., Agaves spp., Yucca sp. , Sporobolus wrightii, Lycurus phalaroi- Peterson et al., Muhlenbergiinae from northeastern Mexico 983 FIG. 20. Muhlenbergia repens [J.R. ReederS C.G. Reeder4045 (ARIZ, US)]. A. Habit. B. Ligule. C. Glumes. D. Floret. Muhlenbergia utilis [AS. Hitchcock 5652 (US)]. E. Habit. F. Rhizome. G. Ligule. H. Glumes. I. Floret. 984 Journal of the Botanical Research Institute of Texas 1(2) des, Aristida sp., and Stipa vobusta; 100-3120 m; southern Utah, southern Colorado, eastern Arizona, New Mexico, western Texas, and throughout Mexico. Specimens examined. MEXICO. Coahuila: 32.2 km SE of Saltillo on road to LosLirios, P.M. Peterson 6219 & C.R. Annable (US); Madera del Carmen, above campo El Dos, P.M. Peterson 18906 &]. Valdes-Reyna (ANSM, US); Municipio de Arteaga, N de La Canada el Carbon, 3 km NO del Ejido Sierra Hermosa, R. Lopez-Aguillon s.n. (ANSM); Columpio, 2 km NO del Ejido Sierra Hermosa, R. Lopez-Aguillon s.n. (ANSM); El Coahuilon, Sierra de la Marta, P. Valdes-Reyna 1836 M.A. Carranza P. (ANSM); SE of San Antonio de las Alazanas and SE of Saltillo at end of road near summit of Coahuilon, P.M. Peterson 8396, 8106, ]. Valdes-Reyna &].A. Villareal (ANSM, US); Puerto Los Tejocotes en la Sierra de Zapaliname, R. Lopez-Aguillon s.n. (ANSM); Sierra La Viga 6 km E de Jame, Puerto Maravillas, J. Valdes-Reyna 1981,].A. Villarreal Q., P.S. Hoge & M.E. Barhvorth (ANSM); Municipio de Miquihuana, Ejido Valle Hermoso, M.H. Cervera 032 (COCA); Municipio de Muzquiz, Station No. 24, ].A. Santos L. 75W (TAES); Municipio de Saltillo, 12 kmN of Zacatecas border on Mexico highway 54, C.W. Morden 509 (ANSM, TAES); 20 km E de Saltillo, carretera Saltillo-Torreon, R. Almeida 1638 (ANSM); 28.2 mi S de Saltillo, carretera 54 a Concepcion del Oro, Zacatecas, P.M. Peterson 10025, C.R. Annable &]. Valdes-Reyna (ANSM, US); 5 km SO de Buenavista, carretera Saltillo-Concepcion del Oro, Zacatecas, P.E. Garcia-Solis s.n. (ANSM); Sierra de Zapaliname, 5 km S Saltillo in San Lorenzo Canyon, 5.L. Hatch 4482, C.W. Morden &]. Valdes-Reyna 4482 (TAES); 21 km SE of Saltillo on Hwy 57 towards Matehuala, P.M. Peterson 15801 &]. Valdes-Reyna (ANSM, US); Buenavista, 7 km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, H. Gonzdlez-Dominguez s.n. (ANSM), C.W. Morden 505, S.L. Hatch, A. Ruiz-Aznar, VM. Valdes-Rodriguez cyJ.S. Marroquin-de la Fuente (ANSM); Escuela Superior Agraria Antonio Narro, Buenavista, PPM. Garza-Cantii s.n. (MEXU); Poblado Carneros, a 40 km por la carretera Federal Numero 54, Saltillo-Concepcion del Oro, Zacatecas, Saldivar 2 (COCA); Rancho Experimental Los Angeles, 48 Km S of Saltillo, carretera 54 Saltillo- Concepcion del Oro, Zacatecas, C.W. Morden 505, 513,]. Valdes-Reyna &].S. Sierra-Tristan (ANSM, TAES), D.H. Rodriguez s.n. (ENCB); 24.2 km S of Saltillo on MEX 54, 16.1 km E of Rancho Experimental Los Angeles, P.M. Peterson 8437 &? M.A. Carranza P. (ANSM, US). Nuevo Leon: El Salero, Sierra Madre Oriental, P.M. Peterson 15820 &]. Valdes-Reyna (ANSM, US); 2.5 mi N of La Siberia on road towards La Encantada, P.M. Peterson 16776, ]. Valdes-Reyna & M. Sosa Morales (ANSM, US); Ejido Tepehuanes, P.M. Peterson 15871 &]. Valdes-Reyna (ANSM, US); El Salero, P.M. Peterson 15820 &]. Valdes-Reyna (ANSM, US); 10.4 mi W of Dieciocho de Marzo up road towards Cerro Potosi, P.M. Peterson 13352 & M.B. Knowles (US); 13.4 mi E of Hwy 57 on Hwy 58 at crossing of Rio Potosi, P.M. Peterson 13310 & M.B. Knowles (US); Municipio de Aramberri, 70 mi N of Matehuala on Hwy 61 towards Linares and 1.5 mi N of La Rosita, P.M. Peterson 13361 & M.B. Knowles (US); Trinidad - Santa Gertrudis, G.S. Hinton 27292 (HINT); Municipio de Bustamante, La Cardona, R. Lopez 012 (COCA); Municipio de Galeana, 32 km N of San Roberto, 18 km S of San Rafael, C.W. Morden 521 (ANSM, TAES); 13 km S of Coahuila border in Nuevo Leon on highway 57, C.W. Morden 521 (ANSM, TAES); Navidad, carretera 57, km 85 al N de Saltillo, F. Cardenas s.n. & M.A. Bernal (MEXU); Hwy 58, 8 Km W of 'Y' intersection, 23 km E of Hwy 57, C.W. Morden 518 (ANSM, TAES); Municipio de General Trevifio, km 55 on Mex 54, E of road, C.W. Morden 507, S.L. Hatch &]. Valdes-Reyna (TAES); Municipio de Santiago, La Escondida, I. Cabral-Cordero 590 (ANSM). Tamaulipas: 101.6 km SW of Ciudad Victoria on MEX 101 towards San Luis Potosi, P.M. Peterson 8323 & R.M. King (US); Municipio de Bustamante, Ejido La Cardona, C.R. Lopez-Aguilar 12 (COCA); Municipio de Miquihuana, Ejido Valle Hermoso,].A. Franco- Lopez 32 (COCA); Municipio de Tula, La Tapona, M.H. Cervera-Rosado 132 (COCA), J.F. Iribe-Duarte 155 (COCA). 28. Muhlenbergia rigens (Benth.) Hitchc, J. Wash. Acad. Sci. 23:453. 1933. (Fig. 13, G-J). Epkampes rigens Benth., J. Linn. Soc, Bot. 19:88. 1881. Ctypsinna rigens (Benth.) M.E. Jones, Contr. W. Bot. 14:8. 1912. TYPE: U.S.A. CALIFORNIA: Sonoma, Sep 1866, H.N. Bolander 6121 (HOLOTYPE: Kl; ISOTYPES: US-323974!, US-323975!). Ctypsinna setiglumis M.E. Jones, Contr. W Bot. 14:8. 1912. TYPE: MEXICO. CHIHUAHUA: Marsh Lake, Sierra Madre Mountains near Garcia in dry pine woods, Sep 1903, M.F.Jones s.n. (HOLOTYPE: POM; ISOTYPE: US-3168556!). Fpicampes leptoura Piper, Proc. Biol. Soc. Wash. 18:143. 1905. Muhlenbergia leptoura (Piper) Hitchc, N. Amer. Fl. 17(6):468. 1935. TYPE: MEXICO. CHIHUAHUA: Sierra Madre Mountains near Colonia Garcia, 2134m, 21 Sep 1899, C.H.T. Townsend & CM. Barber 311 (HOLOTYPE: US-347144!; ISOTYPES: MO-1837827!, US-347144!, US-998992Q. Muhlenbergia marshii I.M. Johnst., J. Arnold Arbor. 24:392. 1943. TYPE: MEXICO. COAHUILA: Sierra del Carmen, 8 Sep 1936, E. G. Marsh ]r. 746 (HOLOTYPE: GH; ISOTYPES: LL, US-1647094!). Muhlenbergia mundula I.M. Johnst. J.Arnold Arbor. 24:392-393. 1943. TYPE: MEXICO. CHIHUAHUA: near Chihuahua, 13 Oct 1885, C.C. Pringle 417 (HOLOTYPE: GH; ISOTYPES: MO-1837822!, US-999023Q. Densely caespitose perennials. Culms (35-)50-150 cm tall, erect, rounded and up to 5 mm thick near base, mostly glabrous below the nodes; internodes glabrous. Leaf sheaths 3-45 cm long, longer than the internodes, glabrous to scaberulous, rounded to keeled and chartaceous near base; ligules 0.5-2(-3) mm long, somewhat firm, decurrent, apex truncate, usually minutely ciliolate; blades 10-50 cm long, 1.5-6 mm wide, flat or involute, stiff, glabrous below and scabrous between the prominent ridges above. Panicles 15-60 cm long, 0.5-1.2 cm wide, narrow, elongate, contracted and spikelike, densely flowered, often interrupted below, grayish-green; primary branches 0.2-4 cm long, ascending and tightly appressed; pedicels 0.2-3 mm long, mostly shorter than the spikelets, hispidulous. Spikelets 2.4-4 mm long, erect, grayish-green; glumes 1.8-3.2 mm long, subequal, shorter than the lemma, scabrous to scaberulous, 1-nerved, apex acute Peterson et al., Muhlenbergiinae from northeastern Mexico 985 or obtuse, occasionally acuminate or notched, mucronate or short awned, the awn up to 1.7 mm long; lem- mas 2.4-4 mm long, lanceolate, unawned, rarely mucronate, glabrous below and scabrous above, short ap- pressed pubescence on the callus, midvein, and margins on the proximal 1/6, the hairs up to 0.4 mm long, apex acute or obtuse, the mucro up to 0.9 mm long; paleas 2.3-3.8 mm long, lanceolate, glabrous below and scabrous above, apex mostly acute; anthers 1.3?1.8 mm long, yellow to purple. Caryopses 1.8-2.2 mm long, fusiform, brownish. In = 40. Phenology.?Flowering August through November. Distribution and habitat.?Sandy washes, gravelly canyon bottoms, rocky drainages, and moist, sandy slopes often along small streams with Pinus spp., P. cembroides, P. chihuahuana, P. rejlexa, Juniperus deppeana,]. flaccida, Quercua spp., Q. greggii, Salvia regla, Abies concolor; Arctostaphylos pungens, A. patula, Ceanothus leuco- dermis, Ganyagrisea, Pwsopis, Cowaniaplieata, Berberissp., Bouteloua curtipendula, Rhus trilobata, Cercocarpus brevijlorus, and Mimosa; 90-2500 m; California, Arizona, southwestern New Mexico, southwestern Texas and scattered in Nevada to northcentral Mexico in Baja California, Baja California Sur, Sonora, Chihuahua, Durango, Aguascalientes, Zacatecas, Jalisco, Michoacan, and Puebla (Espejo Serna et al. 2000). Comments.?A highly variable taxon, M. rigens is morphologically similar to M. macwura and M. dubia. Muhlenbergia rigens can be separated from M. macroura by having glumes shorter than the florets (glumes longer than the florets in M. macroura) and shorter ligules 0.5-2(-3) mm long [ligules (5-)8-40(-50) mm long in M. macroura}. Muhlenbergia rigens can be separated fromM. dubia by having yellow to purple anthers, 1.3?1.8 mm long (anthers greenish, 1.5-2.2 mm long in M. dubia), shorter lemmas, 2.4-4 mm long (lemmas 3.8-5 mm long in M. dubia), and shorter ligules (ligules 4-10 mm long in M. dubia). Muhlenbergia rigens is available commercially as an ornamental. Speciments examined. MEXICO. Coahuila: Municipio de Arteaga, Las Vigas, Canon de la Carbonera, Sierra de Arteaga,J. Valdes-Reyna 1793,}. A. Villarreal Q. <5rM.A. CarranzaP. (ANSM); Municipio de Saltillo, Carneros, camino a la torre de microondas, 3kmO delaestacion. 30 km S de Saltillo,J. Espinosa-Aburto 117 (ANSM); Sierra de Zapaliname Mountains, 5 kmS of Saltillo in San Lorenzo Canyon, S.L. Hatch 4487, C. W. Morden &]. Valdes-Reyna (ANSM, TAES); Sierra Zapaliname, 2 km east of Saltillo up Camino de Quatro (Las Palapas), P.M. Peterson 17855,]. Valdes-Reyna & R.H. Cardenas (ANSM, US); P.M. Peterson 17855 &?]. Valdes-Reyna 18806 (ANSM, US). Nuevo Leon: 13.4 mi E of Hwy 57 on Hwy 58 at crossing of Rio Potosi, P.M. Peterson 13311 & M.B. Knowles (US). 29. Muhlenbergia rigida (Kunth) Kunth, Revis. Gramin. 1:63. 1829. (Fig. 8, D-I). Podosemum rigidum Kunth, Nov. Gen. Sp. (quarto ed.) 1:129. 1816. Trichochloa rigida (Kunth) Roem. & Schult., Syst. Veg. 2:386. 1817. Agrostis rigida (Kunth) Spreng., Syst. Veg. 1:262. 1825. TYPE: MEXICO. GUANAJUATO: near Guanajuato, Sep, F.W.H.A. Humboldt&AJ.A. Bonplands.n. (HOLOTYPE: PI; ISOTYPE: US-91920 fragm. ex PI). Podosemum glabratum Kunth, Nov. Gen. Sp. (quarto ed.) 1:130. 1816. Trichochloa glabrata (Kunth) Roem. & Schult., Syst. Veg. 2:387. 1817. Agrostis glabrata (Kunth) Spreng., Syst. Veg. 1:262. 1825. TYPE: MEXICO. Santa Rosa de la Sierra and Canada de Acabuca, Sep. F.W.H.A. Humboldt & A.J.A. Bonpland s.n. (HOLOTYPE: P-Bonpl.!; ISOTYPE: US-91921 fragm. ex P-Bonpl.!). Muhlenbergia berlandieri Trim, Mem. Acad. Imp. Sci. Saint-Petersbourg, Sen 6, Sci. Math., Seconde Pt. Sci. Nat. 6,4(3-4):299. 1841. TYPE: MEXICO. DISTRITO FEDERAL: Mountains near Mexico, Aug 1827, J.L Berlandier 676, 684 (SYNTYPE: LE-TRIN-1487.01!, both collec- tion numbers appear on the same sheet, with a single specimen and figure); Mexico, 26 Aug 1827, J.L. Berlandier 676 (ISOSYNTYPES: US-2557457!, US-87241 fragm.!, W-2396040; Mexico, ca. Mexico in montibus, J.L Berlandier 684 (ISOSYNTYPE: MO-2974285!, W-1889-239603!)- Muhlenbergia afjinisTiin., Mem. Acad. Imp. Sci. Saint-Petersbourg, Sen 6, Sci. Math., Seconde Pt. Sci. Nat. 6,4(3-4):301. 1841. Podosemum affine (Trin.) Bush, Amen Midi. Naturalist 7(2):40. 1921. TYPE: MEXICO. MEXICO: Toluca, J.L. Berlandier 1083 (ISOTYPES: LE-TRIN- 1485.01 fragm.!, US-87237 fragm.!). Muhlenbergia metcaljei M.E. Jones, Contr. W. Bot. 14:12. 1912. TYPE: U.S.A. NEW MEXICO: Grant Co.: Santa Rita Mountains, 1904, O.B. Metcfll/1485 (ISOTYPE: US!). Densely caespitose perennials. Culms 40-100 cm tall, stiffly erect, glabrous to scaberulous below the basal, terete nodes; usually 1 node per culm; internodes mostly glabrous. Leaf sheaths 2-30 cm long, longer than the internodes, glabrous to scaberulous, rounded near base; ligules (l-)3-12(-15) mm long, often lacerate, firmer below, strongly decurrent; apex obtuse to acute; blades 12-35 cm long, 1-3 mm wide, flat or invo- lute, not falcate, glabrous to scaberulous below and scaberulous to hirsutulous above. Panicles (4-)10-35 cm long, (2-)3-5(-15) cm wide, loosely contracted to open and lax, purplish; primary branches 0.4-10 cm long, sometimes capillary, ascending and spreading up to 80? from the rachises; pedicels 1-10 mm long, 986 Journal of the Botanical Research Institute of Texas 1(2) mostly longer than the spikelets. Spikelets 3.5-5 mm long, purplish; glumes l-1.7(-2) mm long, about equal, 1-nerved, unawned, apex obtuse to subacute, sometimes hirsutulous, rarely mucronate; lemmas 3.5-5 mm long, narrow lanceolate, scaberulous to scabrous, purple, awned, callus with hairs up to 0.5 mm long, apex acuminate, the awn (5-)10-22 mm long, flexuous; paleas 3.5-5 mm long, narrow lanceolate, purple, scaberulous, apex acuminate; anthers 1.7-2.3 mm long, purplish. Caryopses 2-3.5 mm long, fusiform, brownish. 2n = 40, 44. Phenology.?Flowering August through November. Distribution and habitat.?Rocky slopes, ravines, and sandy, gravelly slopes derived from granitic and calcareous substrates associated with Pinus spp., P. cembroides,Juniperus deppeanajuniperus sp., Quercus spp., Arbutus sp., Acacia sp., Arctostaphylos pungens, Brahea sp., Hechtia sp., Cercocarpus breviflorus, Ceanothus sp., Salvia sp., Arbutus sp., Agave sp., Opuntia sp., and Yucca sp.; 1200-2500 m; southeastern Arizona, south- western New Mexico to southwestern Texas, and throughout Mexico and South America along the Andes in Ecuador, Peru, Bolivia, and Argentina. Comments.?This species is highly variable and is one of the most common upland bunchgrasses form- ing almost pure stands in northern Mexico. Muhlenbergia rigida can be distinguished morphologically from M. setijolia by having purplish spikelets (stramineous in M. setijolia), scabrous lemmas (smooth and shiny in M. setijolia), only one node per flowering culm visible (2-4 nodes per culm in M. setijolia), and an evident demarcation between the lemma body and the awn (this not evident in M. setijolia). Another species similar to M. rigida with only a single node per flowering culm is M. purpusii. However, M. rigida has longer lemmas (3.5-5 mm long verses 2.3-3.1 mm long in M. purpusii) that are scaberulous to scabrous (short pilose in M. purpusii). Specimens examined. MEXICO. Coahuila: Sierra El Pino, 26.7 km Wof Rancho El Cimarron, P.M. Peterson 10648 & C.R. Annable (US), 33.5 km W of Rancho El Cimarron, P.M. Peterson 10661 & C.R. Annable (US), 39.5 km W of Rancho El Cimarron, P.M. Peterson 10673 & C.R. Annable (US); 5 mi W of Chapultepec on cutoff road between Hwy 54 & 57, 23 mi S of Saltillo, P.M. Peterson 13273 &M.B. Knowles (US); 30.6 km SE of Saltillo on HWY 57 to San Luis Potosi, P.M. Peterson 6238, 6242 & C.R. Annable (US); 4 km E of Los Lirios on road to Laguna de Sanchez, 50 km SE of Saltillo, P.M. Peterson 6252 & C.R. Annable (US); 12.9 km E of Los Lirios on road to Lagunade Sanchez, 60 km SE of Saltillo, P.M. Peterson 6257, 6263 & C.R. Annable (US); Municipio de Acuna, del Carmen Mountains, E.G. Marsh jr. 719 (MEXU); Madera del Carmen, 12.2 mi NW of Pilares near "old cabin", P.M. Peterson 18884 &]. Valdes-Reyna (ANSM, US); Municipio de Arteaga, Al N de La Canada el Columpio, 2 km NO del Ejido Sierra Hermosa, R. Lopez-Aguillon s.n. (ANSM); Las Vigas, Canon de la Carbonera, Sierra de Arteaga, ]. Valdes-Reyna 1796,].A. Villarreal Q. & M.A. Carranza P. (ANSM); Sierra de Arteaga, El Tunal, carretera estatal 65, PS. Hoge 266, M.E. Barkworth &>]. Valdes-Reyna (ANSM); Municipio de Cuatrocienegas, Sierra de la Madera, Canon Charreteras, Rancho Charreteras,].A. Villarreal Q. 7344, M.A. Carranza P. & R. Rodriguez L. (ANSM); 25 km E of San Roberto along Hwy 58, S.L. Hatch 4574, 4577, C.W. Morden &?]. Valdes-Reyna (TAES); carretera 57, 4.1 km al SW de Pablillo, S.L. Hatch 4999 (TAES); Municipio de Muzquiz, Sierra Maderas del Carmen, E.A. Estrada-Castillon 1784 (ANSM); Sierra del Carmen, Ejido San Francisco, P.M. Peterson 18848,]. Valdes- Reyna & C. Sifuentes (ANSM, US); Madera del Carmen, 12.2 mi NW of Pilares near "old cabin", P.M. Peterson 18890 &]. Valdes-Reyna (ANSM, US); Municipio de Ocampo, Rancho La Rueda, 87 km al NW de Ocampo, D. Barra s.n. (SLPM); Municipio de Ramos Arizpe, Sierra de la Paila,].S. Marroquin-de la Fuente 2343 (ANSM); Sierra de la Paila, Ejido el Cedral por el camino El Carmen, J.A. Villarreal Q. 5379, M.A. Carranza P. & A. Rodriguez G. (ANSM); Municipio de Saltillo, Buenavista, 7 km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas,].A. Villarreal Q. 1413 & M.A. Carranza P. (ANSM); 24 km al S de Chapula, C.E. Zermeho B. 1078 (INEGI); Camino de los Burros, hacia los Aguajes N del Picacho el recreo, en la Sierra de Zapaliname, R. Lopez-Aguillon s.n. (ANSM); Canada Salsipuedes, en la Sierra Zapaliname, 3 km NO de Cuahtemoc, R. Lopez-Aguillon s.n. (ANSM); 2 mi E of Hwy 54 up San Lorenzo Canyon at mouth, P.M. Peterson 13263, ]. Valdes-Reyna &> M.B. Knowles (US); Canon de San Lorenzo, PA. Lobato 21 (COCA); Estacion Carneros, carretera a Zacatecas 30 km S de Saltillo, M.A. Carranza P. 519 & P.M. Peterson (ANSM); 18 mi S of Saltillo on Mexico 54 and 1.3 mi W on road to microondas, just W of Estacion Carneros, P.M. Peterson 8422 cy M.A. Carranza P. (ANSM, US); Hwy 54 S of Estacion Carneros on telephone line service road, M.E. Barkworth 5121, ]. Valdes-Reyna, P. S. Hoge & M.A. Carranza P. (ANSM); Rancho Experimental Los Angeles, 48 km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, J. Espinosa-Aburto 78 (ANSM), S.L. Hatch 4553 & C.W. Morden (ANSM), J. Valdes-Reyna 1903, M.E. Barkworth, P. S. Hoge & M.A. Carranza P. (ANSM),].S. Sierra-Tristan (ANSM, MEXU, COCA); 18 mi S of Saltillo on Mexico 54 and 1.3 Mi W on road to microondas, just W of Estacion Carneros, P.M. Peterson 8423 oy M.A. Carranza P. (ANSM, US); 15 mi S of Saltillo on Mexico 54 and 10 mi E to Rancho Experimental Los Angeles, P.M. Peterson 8435, 8436 and M.A. Carranza P. (ANSM); Terrenos de Tranquitas, R.M. Francois 5830 &>]. Passim (ANSM); Municipio de Torreon, Sierra de Jimulco, 11.7 km Eof Flordejimulco at an abandoned mine, P.M. Peterson 8459, P. A. Fryxell,]. Valdes-Reyna &].A. Villarreal Q. (ANSM, US). Nuevo Leon: 5.6 mi E of junction of Hwy 57 on Hwy 58 towards Linares, P.M. Peterson 13290 & M.B. Knowles (US); 13.4 mi E of Hwy 57 on Hwy 58 at crossing of Rio Potosi, P.M. Peterson J3300, 13301 cy M.B. Knowles (US); 2 mi W of Dieciocho de Marzo up road towards Cerro Potosi, Peterson et al., Muhlenbergiinae from northeastern Mexico 987 P.M. Peterson 13323 & MB. Kncm-les (US); 36 mi NE of Dr. Arroyo on Hwy 61 towards Linares, P.M. Peterson 13369 & U.B. Knowles (US); 5.2mi S of Zaragoza on road towards Ejido La Encantada, P.M. Peterson 16732,]. Valdes-Reyna &M. Sosa Morales (ANSM, US); 14 mi S of the junction of Hwy 58 and Hwy 51 S of Pablillo, S.L. Hatch. 1999 &J. Valdes-Reyna (ANSM); Municipio de Dr. Arroyo, Cruz de Elorza, G.S. Hinton 20631 (HINT); Municipio de Galeana, La Cuesta, G.S. Hinton 19887 (HINT, MEXU); Microondas El Salero, G.S. Hinton 27308, 27310 (HINT); SW of Laguna de Labradores, G.S. Hinton 27922 (HINT); km 63.6 carretera Galeana-San Roberto, I. Cabral-Cordero 1089 (ANSM); Puerto Mexico, carretera 57 km 67 al S de Saltillo, F. Cdrdenas s.n. (MEXU); Municipio de General Zaragoza, Sierra El Soldado, camino a Puerto Pinos,].A. Villa/real Q. 1955, M.A. Carranza P., G. Nesom &]. Norris (ANSM); Municipio de Santiago, El Guardarralla, I. Cabral-Cordero s.n. (ANSM); Las Gomitas, 1. Cabral-Cordero 623 (ANSM); carretera Villa de Santiago-Laguna de Sanchez, km 30.7, P. Jauregui R. 112 (COCA). Tamaulipas: Municipio de Bustamante, Ejido Felipe Angeles, 2 km al NW rumbo a Bustamente, R. Diaz 187 (MEXU); Municipio de Miquihuana, Colonia La Pena, ].A. Barrientos-B. 122 (COCA); Municipio de Palmillas, 101.6 km SW of Ciudad Victoria on MEX 101 towards San Luis Potosi, P.M. Peterson 8316 & R.M. King (US); Ejido Palmillas, R.A. Carranza 228 (COCA). 30. Muhlenbergia robusta (E. Fourn.) Hitchc, N. Amer. Fl. 17(6):462. 1935. (Fig. 17, E-J). Epicampes robusta E. Fourn., Mexic. PI. 2:89. 1886. TYPE: MEXICO. DISTRITO FEDERAL: Santa Fe, 2 Oct 1865, M. Bourgeau 1153 (LECTOTYPI: P!, designated by Hitchcock, N. Amer. Fl. 17(6):462. 1935; ISOLECIOTYPES: K!, US-999036!, US-999031 fragm!, US-90734 fragm!). Epicampes stiicta}. Presl, Reliq. Haenk. l(4-5):235, t. 39. 1830. Muhlenbergiapresliana Hitchc, N. Amer. Fl. 17(6):462. 1935, nom. nov. TYPE: MEXICO. T. Haenke s.n. (HOLOTYPP: PR; ISOTYPPS: LE-TR1N-1558.01 fragm!, US-865970 fragm!). Epicampes berlandieri E. Fourn., Mexic. PI. 2:89. 1886. Muhlenbergia joumieriana Hitchc, J. Wash. Acad. Sci. 23:453. 1933. TYPE: MEXICO. Mexico: Feb 1839,].L Berlandier 670 (LECTOTYPE: P designated by Hitchcock, N. Amer. Fl. 17(6):462. 1935; ISOLPCTOTYPE: US-1127013!). Epicampes macrotis Piper, Proc Biol. Soc Wash. 18:144. 1905. Muhlenbergia macrotis (Piper) Hitchc, N. Amer. Fl. 17(6):463. 1935. TYPE: MEXICO. Zacatecas: Sierra Madre Mountains, ca. 40 km W of San Juan Capistrano, 7 Aug 1897, ].N. Rose 3528 (HOLOTYPE: US-302505!). Epicampes minutijlora Mez, Repert. Spec. Nov. Regni Veg. 17:212. 1921. Muhlenbergia meziana Hitchc, N. Amer. Fl. 17(6):461. 1935, nom. nov. TYPE: MEXICO. Michoacan: near El Canizal, 600m, 15 Jan 1899, E. Langlasse 750 (ISOTYPE: US-386160!). Caespitose perennials. Culms 100-230(-300) cm tall, erect, compressed-keeled near base, glabrous to sometimes pubescent below the nodes; internodes glabrous. Leaf sheaths 15-70 cm long, longer than the internodes below, glabrous, becoming brownish below, sometimes shredded; sheath auricles present, (l-)2-4(-10) cm long, linear subulate to broadly triangular, longer above, straight or twisted, firm below; ligules 2-10(-12) mm long, membranous, lacerate throughout; blades 40-100 cm long, 4-7 mm wide, folded sometimes involute towards tip, scaberulous above and below, the margins and keel saw-toothed. Panicles 30-80 cm long, (2-)3-8 cm wide, narrow to loosely contracted, greenish gray to silvery gray or purplish; primary branches 1?15(?17) cm long, naked on the lower Vi, ascending and closely appressed to spreading up to 40? from the rachises; pedicels 0.3-1.1 mm long, shorter than the spikelets, erect, scaberulous; central axis prominently ribbed, scabrous. Spikelets (1.8-)2-3(-3.2) mm long, erect, greenish gray or purplish; glumes 1.8-3.2 mm long, usually longer than the floret, subequal, narrowly oblong to elliptic, unnerved to indistinctly 1-nerved, hyaline to greenish-gray, glabrous to scaberulous, apex acute to obtuse occasionally erose; lemmas 1.7-2.6 mm long, linear oblong, unawned or rarely mucronate, greenish to yellowish-brown, glabrous or pubescent with scattered hairs on lower V2, the hairs up to 0.3 mm long, callus glabrous or with a few hairs, apex acute, the mucro when present up to 1 mm long; paleas 1.7-2.6 mm long, glabrous to sparingly pilose between the nerves on the lower V2, apex acute; anthers 1.1-2 mm long, purplish. Caryopses 1.2-1.7 mm long, fusiform, brownish. 2n = 40. Phenology.?Flowering July through April. Distribution and habitat.?Muhlenbergia robusta occurs in mountainous areas from Sinaloa and Chihua- hua south to Chiapas and Central America; found on rocky slopes, along barrancas, pine, pine-oak, and/or pine/fir forests, and tropical deciduous forests with Carya sp., Pinus spp., Arbutus sp., and Quercus spp.; 850-3000 m. Comments.?This species is highly variable. Historically, M. macrotis was separated from M. robusta by having sheath-auricles from 1-10 cm long whereas M. robusta has sheath-auricles 2-5 mm long or lacking. The length of sheath-auricles seems to be under environmental control since we can find no discrete length classes to separate these forms. This character varies widely on individuals within a population and there appears to be no other character that can be used to separate these two forms. 988 Journal of the Botanical Research Institute of Texas 1(2) Specimens examined. MEXICO. Coahuila: Municipio de Saltillo, Lomas de Lourdes, Saltillo, P. Lobato 040 (COCA). Nuevo Leon: 9.2 mi NE of Dulces Nombres, P.M. Peterson 15928 &]. Valdes-Reyna (ANSM, US). 31. Muhlenbergia setifolia Vasey, Bot. Gaz. 7(8-9):92. 1882. (Fig. 15, D-G). TYPE: U.S.A. TEXIS: western Texas, Guadalupe Mountains, V Havard s.n. (HOLOTYPE: US-81634!, W-1916-29061!). Caespitose perennials. Culms 30-85 cm tall, erect, slender, slightly decumbent near base, hirsutulous below the terete nodes, 2-4 nodes per culm; internodes glabrous to hirsutulous. Leal sheaths 2-13 cm long, shorter than the internodes, glabrous to puberulent, basal sheaths rounded, margins whitish; ligules 4-7(-10) mm long, membranous, firm below, decurrent, margins glabrous to puberulent and wider than V2 the adjacent blade width, apex acuminate, lacerate; blades 5-20(-25) cm long, 0.2-1.2 mm wide, tightly involute, fal- cate, scaberulous below and scaberulous to hirsutulous above, the hairs less than 0.1 mm long. Panicles 8-20(-25) cm long, (2-)3-5 cm wide, loosely contracted, ovate; primary branches 0.5-7 cm long, capillary, ascending, appressed or spreading up to 70? from the rachises; pedicels 3-20 mm long, mostly longer than thespikelets, delicate, flexuous, glabrous and smooth. Spikelets 3.5-5.1 mm long; glumes 1.5-2.5 mm long, subequal, thin and hyaline, often purplish near base; lower glumes unnerved, apex truncate or obtuse, often toothed or notched; upper glumes 1-nerved or unnerved, apex obtuse to acute often mucronate, the mucro less than 0.7 mm long; lemmas 3.5-5.1 mm long, narrow lanceolate, glabrous, smooth and shining, stramineous, awned, callus with hairs up to 0.6 mm long, apex acuminate, demarcation of lemma body and awn not evident, the awn 10-30 mm long, flexuous; paleas 3.5-5.1 mm long, as long as the lemma, narrow lanceolate, glabrous, apex acuminate; anthers 2-2.6 mm long, greenish. Caryopses 2.4-3.2 mm long, fusiform, brownish. In = 40. Phenology.?Flowering June through November. Distribution and habitat.?Muhlenbergia setifolia grows on calcareous rocky slopes, rock outcrops, and in desert grasslands associated with Quercus spp., Q. saltensis, Juniperus deppeana, J. flaccida, Pinus eembroides, Larrea tridentata, Parthenium argentatum Agave lecheguilla, Fallugia paradoxa, Rhus virescens, Acacia berlandieri, Dasylirion longissimum, Karvinskia humboldtiana, Salvia regla, Cowania plicata, Mimosa sp., Berberis sp., Prunus sp., Bouteloua spp., B. curtipendula, Aristida sp., and Sorghastrum sp.; 1000-2250 m. Muhlenbergia setifolia also ranges to western Texas and New Mexico, U.S.A.. Comments.?Muhlenbergia setifolia is very similar to M. rigida but differs from the latter by having lem- mas that are smooth, shining, and stramineous; leaf blades that are tightly involute, falcate, and narrow (0.2-1.2 mm wide); culms usually with 2-4 nodes; and greenish anthers. Muhlenbergia setifolia can be easily confused with M. purpusii, another species commonly found on calcareous habitats. However, Muhlenbergia purpusix has smaller spikelets (2.4-3.2 mm long, pilose lemmas and paleas, shorter anthers (1.6-2 mm long), shorter caryopses (1-1.2 mm long), and only a single, basal node per culm. Specimens examined. MEXICO. Coahuila: 35.4 km W of Ocampo at Cuesta Zozaya, P.M. Peterson 8368 &]. Valdes-Reyna (US); 140.3 km NW of Muzquiz on Hwy 53 towards Boquilla del Carmen, P.M. Peterson 10599 & C.R. Annable (US); 135.4 km NW of Muzquiz on Hwy 53 towards Boquilla del Carmen, P.M. Peterson 10587 & C.R. Annable (US); Sierra El Pino, 9.6 km SW of Rancho El Cimarron, P.M. Peterson 10637 & C.R. Annable (US); Sierra El Pino, 39.5 km W of Rancho El Cimarron, P.M. Peterson 10669 & C.R. Annable (US); Sierra La Lagunita; 6.4 mi SE of Aramberri on road towards Agua Fria, P.M. Peterson 16687,]. Valdes-Reyna & M. Sosa Morales (ANSM, US); Municipio de Acuria, Serranias del Burro, Rancho El Bonito, Canon el Toro, J. Valdes-Reyna 1182 cy D.H. Riskind (ANSM); Canon Los OjitosJ. Valdes-Reyna 1250, 1260 & D.H. Riskind (ANSM); Municipio de Arteaga, Puerto de las Flores, R.M. Francois 183 (ANSM); 18 mi E of Saltillo, J.R. Reeder 5000 &> C.G. Reeder (ENCB); Municipio de Castahos, Paso de San Lazaro, Sierra de la Gavia, 37.6 mi S of Monclava on Mex 57 towards Saltillo, P.M. Peterson 9977, 9979, C.R. Annable &]. Valdes-Reyna (ANSM, US); Paso de San Lazaro, Sierra de la Gavia, Municipio de General Cepeda, 20 km sobre la carretera de General Cepeda-Parras, J. Espinosa-Aburto 147 (ANSM); Municipio de Muzquiz, Rancho Santo Domingo, J. A. Santos-Ls.n. (ANSM); 26 mi NW of Rancho Margareta, 90 mi NW of Sabinas, F.W. Gould 10688 (TAES); La Cuesta del Plomo on the Muzquiz-Boquillas hwy, J. Cano 19 (TAES); Sierra La Encantada, 140 km al N de Muzquiz, entronque Boquillas del Carmen brecha & tunel, Flourita de Mexico Unidad Minera, 6 km al SO pasando el tunel, M.A. CarranzaP. 710,]. Valdes-Reyna, P.A. Fryxell & R. VdsquezA. (ANSM, MEXU); Municipio de Parras, Rancho El Tunal, 25 km al ESE de Parras de la Fuente, C.P. Cowan 3669 (TAES); Municipio de Ramos Arizpe, Canada el Diente, Sierra de la Paila, J.A. Villarreal Q. 4811 & M.A. Carranza P. (ANSM); Sierra de la Paila (Lado Norte) Canada Becerros, J.A. Villarreal Q. 5468, M.A. Carranza P. & L. Arce G. (ANSM); Sierra de la Paila, Ejido el Cedral por el camino El Carmen, J. Valdes-Reyna 2183, J.A. Villarreal Q. 5378, M.A. Carranza P. & A. Rodriguez G. (ANSM); Sierra de la Paila, Valle de Parrehos, J.A. Villarreal Q. 4171, J.L. Elizondo E. &J.J. Lopez (ANSM); Municipio de Saltillo, Cerro del Pueblo, O de la Ciudad de Peterson et al., Muhlenbergiinae from northeastern Mexico 989 Saltillo, ]. Valdes-Reyna 2054, M. Martinez M. & M.A. Carranza P. (ANSM, MEXU); San Lorenzo Canyon, 6 mi SE of Saltillo, E. Palmer 400 (US); 6 km S of Saltillo, land owned by Universidad Autonoma Agraria "Antonia Narro", P.M. Peterson 8346 &]. Valdes-Reyna (ANSM, US); Carneros, camino a la torre de microondas, 30 km al S de Saltillo, J. Espinosa 103 (TAES); alrededores de la Escuela de Agricultura "Antonio Narro", J.G. Garcia G. s.n. (1BUG); Rancho Demostrativo "Los Angeles" 48 km al S de Saltillo, J. S. Sierra PR04 (ENCB); Estacion Carneros, carretera a Zacatecas 30 km S de Saltillo, M.A. Carranza P. 517 &> P.M. Peterson (ANSM); Paso de Carneros, al S de Saltillo, J.S. Marroauin-de la Fuente 3056 (ANSM); Rancho experimental Los Angeles, 48 km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, J.S. Sierra-Tristdn s.n. &>]. Valdes-Reyna (ANSM); 29 km S of Saltillo on Mex 54 and 2.1 km W on road to Microdoonas, just W of Estacion Carneros, P.M. Peterson 8417 cy M.A. Carranza P. (ANSM, US); Municipio de San Buenaventura, Sierra La Encantada, Rancho Carrizalejo, entrada S al rancho Puerto del Aire, M.A. Carranza P. 725, J. Valdes-Reyna, P.A. Fryxell, R. Vdsquez A. &>0. Meza (ANSM); 9 km al SW del Rancho El Cimarron, J. Blando Navarrete 8109181 (INEGI). Nuevo Leon: Municipio de Galeana, Near Puerto Mexico along highway 57, S.L. Hatch. 5009, C.W. Morden &]. Valdes-Reyna (TAES); Municipio Mier & Noriega, N of Tapona Morena, G.S. Hinton 27335 (HINT); Municipio de San Pedro, 16 km al NE de San Fernando, Sierra La Fragua, Ft. Garcia G. s.n.(INEGI); Municipio de Santiago, Las Gomitas, I. Cabral-Cordero 617 (ANSM); Sierra Zapaliname, at 2 km east of Saltillo up Camino de Quatro (Las Palapas), P.M. Peterson 17854, ]. Valdes-Reyna & R.H. Cardenas (ANSM, US); Sierra Zapaliname, along camino "El Cuatro", E of Saltillo, P.M. Peterson 18811, ]. Valdes-Reyna & R.H. Cardenas (ANSM, US). 32. Muhlenbergia spiciformis Trin., Mem. Acad. Imp. Sci. Saint-Petersbourg, Ser. 6, Sci. Math., Seconde Pt. Sci. Nat. 6,4(3-4):288. 1841. (Fig. 14, E-I). TYPE: MEXICO. "Southern Mexico," Karwinsky s.n. (LECIOTYPE: W! here designated, sheet is annotated by C.B. Trinius; ISOLECTOTYPE: LE fragm!). Muhlenbergia acutijolia E. Fourn., Mexic. PI. 2:86. 1886. TYPE: MEXICO.Veracruz: Orizaba, 8 Nov 1866, M. Bourgeau 3327 (HOLOTYPE: P!; ISOTYPES: MO-2974301!, US-87235 fragm!, US-2561240!). Muhlenbergia parviglumis Vasey, Contr. U.S. Natl. Herb. 3(1):71. 1892. TYPE: U.S.A. Texas: 1887, G.C. Nealley s.n. (HOLOTYPE: US-81638!; ISOTYPE: US-994967!). Caespitose perennials, often short-lived and appearing as annuals. Culms 25-80 cm tall, erect, slender and wiry, freely branching at the base, strigose to glabrous below the nodes; internodes mostly glabrous, usu- ally 4-8 nodes per culm. Leaf sheaths 3.5-12 cm long, shorter than the internodes, scaberulous; ligules 1-3 mm long, deeply lacerate, margins hyaline, apex acuminate; blades 2-12 cm long, 1-3 mm wide, flat to involute, hirsutulous to scabrous above and scaberulous below. Panicles 4-18 (-20) cm long, (0.6-)l-2.8 cm wide, narrow, contracted, sometimes interrupted below, loosely flowered; primary branches 0.6-5 cm o long, ascending and appressed occasionally spreading up to 30 from the rachises; pedicels 0.1-3.0 mm long. Spikelets 2.8-4 mm long, erect; glumes 0.3-1.0 mm long, less than V2 as long as the lemma, 1-nerved, unequal, apex obtuse to acute, sometimes erose; lower glumes shorter than the upper glumes; lemmas 2.8-4 mm long, narrowly lanceolate, awned, purplish, scabrous roughened, sparsely appressed-pubescent on the calluses and lower % of the midveins and margins, the hairs less than 0.3 mm long, apex acuminate, the awn (10-)20-40 mm long, straight to flexuous; paleas 2.6-3.9 mm long, narrowly lanceolate, sparsely pu- bescent between the nerves on the basal 1/3, apex acuminate, scabrous; anthers 0.9-1.6 mm long, purplish. Caryopses 2-2.6 mm long, fusiform, brownish. In = 40. Phenology.?Flowering July to November. Distribution and habitat.?Muhlenbergia spiciformis grows on rocky slopes, cliffs, and calcareous rock outcrops, often in thorn-scrub and open woodland communities associated with Quercus spp., Pinus spp., P. cembroides, Juniperus deppeana, Pseudotsuga menziesii, Abies sp., Cupressus sp., Agave sp., Ceanothus sp., Acacia sp., Cornus stolonijera, Salvia sp.,Juglans sp., Arbutus sp., Opuntia, sp., Fraxinus sp., Bouteloua sp., and Aristida sp.; 450-2800 m. This species ranges from southern New Mexico and southwestern Texas, and is found in Mexico in Chihuahua, San Luis Potosi, Hidalgo, Michoacan, Jalisco, Oaxaca, Queretaro, Veracruz, and Chiapas to NC Mexico. Flowering July to October. Specimens examined. MEXICO. Coahuila: Madera del Carmen, 9.5 mi NW of Pilares, P.M. Peterson 18880 &]. Valdes-Reyna (ANSM, US); 27.4 km SE of Saltillo and 12 km NW of Jame at Bosque de Montana, P.M. Peterson 10074, C.R. Annable &]. Valdes-Reyna (US); Sierra El Pino, 33.5 kmW of Rancho El Cimarron, P.M. Peterson 10658 &> C.R. Annable (US); 9.7 km E of Los Lirios on road to Laguna de Sanchez, P.M. Peterson 6255 & C.R. Annable (US); Municipio de Acuna, Del Carmen mountains, E.G. Marshjr. 717 (MEXU); Municipio de Arteaga, 32.2 km SE of Saltillo on road to Los Lirios, P.M. Peterson 6244 & C.R. Annable (US); Sierra de Arteaga, El Tunal, P.S. Hoge 280, M.E. Barkworth csj. Valdes-Reyna (ANSM); Sierra Madre Oriental. SE of San Antonio de las Alazanas and SE of Saltillo at end of road near summit of Coahuilon, P.M. Peterson 8402,].A. Villarreal Q. &J. Valdes-Reyna (US, ANSM); Municipio de Monclova, Rancho Agua Bueno, 43 mi N of Monclova, F.W. Gould 6410 (ANSM, TAES); Sierra de la Gloria, Canon El Cono, near El Chilpitin, PL. Wendt 1604 & D.H. 990 Journal of the Botanical Research Institute of Texas 1(2) Riskind (ANSM, UT); Municipio de Miizquiz, 137.9 km NW of Muzquiz on Hwy 53 towards Boquilla del Carmen, P.M. Peterson 10590 & C.R. Annable (US); Madera del Carmen, Wooded canyon above Campo El Dos, P.M. Peterson 18915 &]. Valdes-Reyna (ANSM, US); Sierra Santa Rosa, R. Vdsquez-Aldape s.n. (ANSM); Sierra del Carmen, Ejido San Francisco, P.M. Peterson 18859,]. Valdes-Reyna & C. Sifuentes (ANSM, US); Municipio de Ocampo, 10 km Saltillo towards General Cepeda, J. Espinosa-Aburto 132 (ANSM); 7.5 km al W del Rancho La Palma, Sierra La Encantada, J. Blando Navarrete 810971 (1NEG1); Municipio de Ramos Arizpe, 36 mi S of Castanos, J.R. Reeder 4813 cy C. G. Reeder (MEXU); Paso de San Lazaro, al N de Ramos Arizpe, carretera 57, 3 mi S of restaurant La Muralla, P.M. Peterson 8361 & ]. Valdes-Reyna (ANSM, US); Municipio de Saltillo, 3.5 mi E of Hwy 54 up San Lorenzo Canyon, P.M. Peterson 13259, ]. Valdes-Reyna & M.S. Knowles (US); 5 mi W of Chapultepec on cutoff road between Hwy 54 & 57, 23 mi S of Saltillo, P.M. Peterson 13272 & M.B. Knowles (US); km 25 carretera Saltillo-Monclova, R. Almeida 1593 & M. Torres H. (ANSM); Lomas de Lourdes, M. Saldivar 6 (COCA); N del canon el Carbon 3 km NW of Ejido Sierra Hermosa, R. Lopez-Aguillon s.n. &> T.L. Wendt (ANSM); Rancho experimental Los Angeles, 48 km S of Saltillo, carretera 54 Saltillo-Concepcion del Oro S.L. Hatch 4548, C.W. Morden &]. Valdes-Reyna (ANSM, TAES), J.J. Villarrea Q. 6704, J.S. Sierra-Tristan, M.A. Carranza P. & D.E. Lozano (ANSM); 5 km S of Saltillo, in San Lorenzo Canyon, S.L. Hatch, 4496, C.W. Morden & ]. Valdes-Reyna (TAES); Sierra Madre Oriental, 15 mi S of Saltillo on Mexico 54 and 10 mi E to Rancho Experimental Los Angeles of the Universidad Autonoma Agraria Antonio Narro, P.M. Peterson 8433 & M.A. Carranza P. (ANSM, US). Nuevo Leon: 6.1 km S of Allende on MEX 85 towards Montemorelos, P.M. Peterson 8334 & R.M. King (US); 16 km E of Los Lirios and 19.3 km W of Laguna de Sanchez, P.M. Peterson 6270 & C.R. Annable (US); 8.8 km W of Laguna de Sanchez and 29 km E of Los Lirios, P.M. Peterson 6271 & C.R. Annable (US); Municipio de Galeana, 25 km E of San Roberto along highway 58, S.L. Hatch 4562, C.W. Morden &]. Valdes-Reyna (ANSM, TAES); 5.6 mi E of junction of Hwy 57 on Hwy 58 towards Linares, P.M. Peterson 13295 &M.B Knowles (US); 13.4 mi E of Hwy 57 on Hwy 58 at crossing of Rio Potosi, P.M. Peterson 13309 &> M.B Knowles (US); 3 mi Wof Dieciocho de Marzo up road towards Cero Potosi, P.M. Peterson 13327 &> M.B. Knowles (US); Highway-Potrero Prieto, G.B. Hinton 28109 (HINT); carretera Galeana-La Asencion, a 1.5 km de San Felipe, M. Castillo 211& N. Bazaldu (COCA); Municipio de Garcia, Villa Garcia, C. Diaz L. s.n. (GUADA); Municipio de General Zaragoza, 4km S of Zaragosa at junction of road to Cerro Viejo-Tepehuanes, P.M. Peterson 15847 cVJ, Valdes-Reyna (ANSM, US); Sierra La Lagunita; 6.4 mi SE of Aramberri on road towards Agua Fria, P.M. Peterson 16685,]. Valdes-Reyna &M. Sosa-Morales (ANSM, US); 5.2mi S of Zaragoza on road towards Ejido La Encantada, P.M. Peterson 16737,]. Valdes-Reyna & M. Sosa-Morales (ANSM, US); Sierra El Soldado, camino a Puerto Pinos, ].]. Villarreal Q. 4956, M.A. Carranza P., G. Nesom &]. Norris (ANSM, MEXU); Municipio de Iturbide, Bosque-escuela, Universidad Autonoma de Nuevo Leon, 12 km E de Iturbide, 1. Cabral-Cordero 1078 (ANSM, UAT); Municipio de Linares, Las Palmas-El Pinal, ].]. Ortiz-Diaz 23 (ANSM); El Rancho El Nogalar, carretera Linares-San Roberto, km 12, M.M. Castillo-Badillo (COCA); km 169 carretera Monterrey-Linares en El Chocolate, J. Garza 166 & M.M. Castillo-Badillo (COCA); Los Pinos, J.J. Ortiz-Diaz s.n. (ANSM, ENCB); Municipio de Montemorelos, 20 km NW of Montemorelos, J.N. Weaver 591 (TAES); Municipio de Monterrey, Sierra Madre, H.C. Muel- ler 395 & M. T. Mueller (MEXU); 9 km S of El Ca.do on Monterrey-Mexico City hwy, F.W. Gould 6340 &]. Ortega (TAES); Municipio de Rayones, Galeana-Rayones, G.B. Hinton 20835, 20859 (HINT); Municipio de Santiago, Camino a la Cola de Caballo, P. ]auregui-Ramirez 52 (COCA); La Escondida, I. Cabral-Cordero 597 (ANSM). Tamaulipas: 14.6 mi NE of Dulces Nombres, P.M. Peterson 15919 &]. Valdes- Reyna (ANSM, US); Municipio de Hidalgo, Paso de la Muerte, A. Brito 109 (COCA); Municipio de Jaumave, Ejido Avila y Urbina, J.F. Iribe-Duarte 240 (COCA); Sierra Madre rumbo a Jaumave, A. Brito 40 (COCA); Municipio de Palmillas, 88.7 km SW of Ciudad Victoria on MEX 101 towards San Luis Potosi, P.M. Peterson 8332 & R.M. King (US); Municipio de San Carlos, La Begonia, 2 km S de San Jose, Sierra San Carlos, O.L. Briones-Villarreal 1306 (ANSM); Municipio de Victoria, Altas Cumbres, G. Bores-Kulman 88 (COCA). 33. Muhlenbergia stricta (J. Presl) Kunth, Enum. PI. 1:202. 1833. (Fig. 7, D-H). PodosemumstdctumJ. Presl, Reliq Haenk. l(4-5):230. 1830. TYPE: MEXICO. T. Haenhe s.n. (HOLOTYPE: PR). Muhlenbergia elata Vasey Contr. U.S. Natl. Herb. 1(8):282. 1893. TYPE: MEXICO. JALISCO: near Guadalajara, Jul-Oct 1886, E. Palmer 770 (HOLOTYPE: US-81624!; ISOTYPES: LEI, MO-2974305!, MO-2974306!, US-822890Q. Muhlenbergia longifolia Vasey, Contr. U.S. Natl. Herb. 1(8):283. 1893. TYPE: MEXICO. JALISCO: Rio Blanco, 1886, E. Palmer 523 (HOLOTYPE: US-995747!; ISOTYPES: MO-2947307!, US-822923!). Caespitose perennials. Culms 74-150 cm tall, erect, glabrous to pubescent below the terete nodes; usually 2 or 3 nodes per culm; internodes glabrous to sparingly pubescent. Leaf sheaths 15-35 cm long, glabrous to pubescent, closely overlapping at the base and rounded, the lower usually pubescent; ligules 2-5 mm long, chartaceous, firm and brownish below, strongly decurrent, apex obtuse to truncate; blades 20-65 cm long, 1-3 mm wide, flat or involute, not falcate, glabrous below and scaberulous to hirsutulous above. Panicles 15-60 cm long, 5?12(?15) cm wide, open, loose, diffuse, ovoid to pyramidal, dark greenish-purple; primary branches mostly 2-12 cm long, capillary, ascending and spreading up to 45? from the rachises, whorled; pedicels 1-7 mm long, mostly longer than the spikelets but some of the lateral pedicels shorter than the spikelets. Spikelets (2-)2.4-3.6 mm long, dark green; glumes 0.8-2 mm long, shorter than the lemma, subequal, 1-nerved, apex obtuse to subacute or erose, apex often mucronate or short-awned; lower glumes 0.8-1.5 mm long; upper glumes 1-2 mm long, usually mucronate or short-awned, the mucros or awns 0.4-1.2 mm long; lemmas (2-)2.4-3.6 mm long, narrow lanceolate, glabrous, dark green, awned, callus Peterson et al., Muhlenbergiinae from northeastern Mexico 991 with hairs up to 0.3 mm long, apex acuminate, sometimes scaberulous, the awns 5-15 mm long, flexuous; paleas (2-)2.4-3.6 mm long, as long as the lemma, narrow lanceolate, glabrous, apex acuminate; anthers 1.1?1.6 mm long, greenish to purplish. Caryopses 1.5-1.7 mm long, fusiform, brownish. 2n = 32 (J.R. Reeder 4721 & C.G. Reeder, US-2541318!), ca. 40 (J.R. Reeder 6389 & C.G. Reeder, US-2769903!). Phenology.?Flowering September through November. Distribution and habitat.?In Tamaulipas, M. strieta was found growing on calcareous derived rocky slopes in thorn-scrub with species of Agave, Yucca, Dasylirion, and Juniperus. Muhlenbergia strieta is endemic to Mexico and has been reported from the states of Colima, Durango, Guanajuato, Jalisco, Mexico, Micho- acan, Morelos, Nayarit, Oaxaca, Veracruz and Zacatecas (Espejo Serna et al. 2000); 1100-2100 m. This is the first report of M. strieta for Tamaulipas. Comments.?Muhlenbergia strieta is morphologically very similar to M. capillaris (Lam.) Trin., a species known from lower elevations (0-500 m) of the southeastern USA, the Caribbean Islands, the Atlantic slopes of Veracruz, and the Yucatan (McVaugh 1983; Peterson 2003). In M. capillaris the pedicels are always longer than the florets (verses some of the lateral pedicels shorter than the spikelets in M. strieta), the spikelets range from (3-)3.5-5 mm long [verses (2-)2.4-3.6 mm], and the lower sheaths are mostly glabrous (verses usually pubescent). Muhlenbergia rigida is also morphologically similar to M. strieta, but the former species has larger spikelets 3.5-5 mm long, unawned glumes, and glabrous basal sheaths. It is somewhat difficult to make correct determinations of some individual specimens especially if you have a glabrous form of M. strieta and the exact collection locality is not known. Specimens examined. MEXICO. Tamaulipas: Municipio de Palmillas, 63 mi SW of Ciudad Victoria on Mex 101 towards San Luis Potosi, P.M. Peterson 8324 & R.M. King (US). 34. Muhlenbergia tenuifolia (Kunth) Kunth, Revis. Gramin. 1(4):63. 1829. (Fig. 5, E-H). Calamagmstis tenuijolia Kunth, Nov. Gen. Sp. (quarto ed.) 1:134. 1816. Arundo tenuijolia (Kunth) Poir., Encycl. 4:704. 1816. Podosemum tenuifolium (Kunth) Nees ex Nees & Schauer, Linnaea 19(6):690. 1847. TYPE: MEXICO. DISTRITO FEDERAL: Mexico City, Apr, EW.H.A. Humboldt & A.].A. Bonpland s.n. (HOLOTYPE: P-BONPL!; ISOTYPES: photo K!, microfiche US!, P!). Calamagrostis quitensis Kunth, Nov. Gen. Sp. (quarto ed.) 1:133?134. 1816. Arundo quitensis (Kunth) Poir., Encycl. 4:704. 1816, nom illeg. hom., non Arundo quitensis Spreng., 1815. Muhlenbergia quitensis (Kunth) Hitcho, Contr. U.S. Natl. Herb. 17(3):292. 1913. TYPE: MEXICO. GUERRERO: Sochipala et Valle Zopilote, Apr, F.W.H.A. Humboldt & A.J.A. Bonpland s.n. (HOLOTYPE: P-BONPL!; ISOTYPES: photo K!, microfiche US!, P!). Muhlenbergia longiseta Benth., PI. Hartw. 28. 1840. TYPE: MEXICO. AGUASCALIENTES: Aguas Calientes, Hartweg248 (HOLOTYPE: K!; ISOTYPES: K!, NY!, P!, US-91927 fragm. ex Wl). Muhlenbergia monticola Buckley, Proc. Acad. Nat. Sci. Philadelphia 14:91. 1862. TYPE: U.S.A. TEXAS: side of hills in the Pass of the Limpia, 24 May 1849, C. Wright 731 (LECTOTYPE: PH! designated by Dorr & Peterson, Sida 15:591. 1993; ISOLECTOTYPES: MO!, US-81641!). Muhlenbergia sylvatiea var. flexuosa Vasey Rep. U.S. Geogr. Surv, Wheeler 6:284-285. 1879. TYPE: U.S.A. ARIZONA: Camp Crittenden, 1874, Rothrock 681 (LECTOTYPE: US-995253! designated by Hitchcock, N. Amer. Fl. 17:474. 1935). Loosely caespitose to densely tufted, annuals to short-lived perennials with delicate bases, flowering the first year. Culms 20-70 cm tall, erect or decumbent at the base, branching at the lower and middle nodes, scaberulous below the terete nodes; internodes generally 2.0-9.5 cm long. Leaf sheaths 4.0-7.5 cm long, glabrous or scaberulous, commonly shorter than the internodes; ligules 1.2-3.0(-5.0) mm long, membra- nous, apex acute, often lacerate with age; blades 2-13 cm long, 1.2-2.5 mm wide, flat or loosely involute, scaberulous to glabrous below and scabrous above. Panicles 7-20 cm long, 1.0-6.5 cm wide, narrow and contracted to loosely spreading, interrupted below, terminal and axillary, 15-23 nodes per panicle; primary branches 3.5-7.5 cm long, usually one per node, when immature the branches mostly appressed and ascend- ing, when mature the branches sometimes widely spreading up to 70? from the rachises; pedicels 1-3 mm long, usually shorter than the spikelets, antrorsely scabrous, stout, appressed or spreading. Spikelets 2-4 mm long, erect, often purplish; glumes 1.2-2.8 mm long, unequal, 1-nerved, scabrous along the nerves, apex acute to acuminate, often mucronate or erose, the mucro up to 0.5 mm long; lower glumes 1.2-2.0 mm long; upper glumes 1.5-2.8 mm long, more than Vi as long as the lemma; lemmas 2.0-3.5(-4.0) mm long, lanceolate, widest near base, awned, scaberulous above and villous on proximal Vi along the margins and 992 Journal of the Botanical Research Institute of Texas 1(2) the midvein, the hairs 0.5-1.5 mm long, callus short-pubescent, the awn 10?30(?40) mm long, scabrous, flexuous; paleas 1.8?3.4(?3.8) mm long, lanceolate, sparsely appressed pubescent between the nerves on the proximal V2; anthers 0.9-1.5 mm long, yellowish. Caryopses 1.0-2.2 mm long, narrowly fusiform, terete, brownish. In = 20, 40. Phenology.?Flowering July through November. Distribution and habitat.?Muhlenbergia tenuijolia grows on rocky slopes, limestone rock outcrops, gravelly roadsides, and sandy drainages in grama grasslands with Pinus cembroides, Yucca, sp., Agave sp., Acacia sp., Bouteloua sp., Quercus sp., and Opuntia sp., and in pine-oak woodlands; 1200-2500 m; southern Arizona, New Mexico, and Texas, U.S.A. south throughout Mexico in the Mountains and in Venezuela, Bolivia, Peru, and Argentina (Peterson & Annable 1991; Zuloaga et al. 1994). Comments.?Muhlenbergia tenuijolia can be separated from M. microsperma by having longer acute to acuminate glumes (1.2-2.8 mm long) and by lacking cleistogamous panicles present in the axils of the lower sheaths. Muhlenbergia tenuijolia shows tremendous variation in overall plant size, ranging from small first-year flowering individuals to large, caespitose or densely tufted short-lived perennials. Muhlenbergia spicijormis is morphologically similar but can be separated from M. tenuijolia by possessing short glumes (0.3-1.0 mm long) that are often obtuse at the apex and lemmas with longer awns [(10-)20-40 mm long]. Specimens examined. MEXICO. Coahuila: Municipio de Acuna, Del Carmen mountains, E.G. Marsh jr. 872 (MEXU); Municipio de Arteaga, 10.5 mi SW of Arteaga, 22.5 mi SW of Saltillo, F.W. Gould 8695 (TAES); Las Vigas, Canon de la Carbonera, Sierra de Arteaga, J. Valdes-Reyna 1800, J.A. ViUarreal Q. & M.A. Carranza P. (ANSM, ENCB); Jame a Rayones, G.S. Hinton 27808 (HINT); Municipio de Castanos, Paso de San Lazaro, Sierra de la Gavia, 37.6 mi S de Monclova, hwy 57, P.M. Peterson 9980, C.R. Annable & J. Valdes-Reyna (ANSM, US); S end of Puerto San Lazaro at Cuesta La Muralla, alon hwy 57, J. Valdes-Reyna 1103 & T.L. Wendt (ANSM); Sierra de La Gavia, Rancho La Gavia, 3 km S de la casa por el canon, M.A. Carranza P. 2299 &J.A. Encina D. (ANSM); Municipio de Cuatrocienegas, l/i mi N of mouth of canon de la Hacienda, near turnoff to Canon del Agua, J. Valdes-Reyna 991 & T.L. Wendt (ANSM, TAES); 1 km NE of Mina La Reforma, Sierra de la Purisima, M.C. Johnston 10326, T.L. Wendt & F. Chiang C. (MEXU, TAES); Cation del Agua, mouth of canyon, vicinity of Ranchito, J. Valdes-Reyna 1007 cy T.L. Wendt (ANSM, TAES); Sierra de la Madera, Canon Charreteras, Rancho Char- reteras, ].A. ViUarreal Q. 7345, M.A. Carranza P. & R. Rodriguez L. (ANSM); Sierra de San Marcos, Canon Grande, Ejido Estanque de Norias, M.A. Carranza P. 1706, j.A. Encina D.,]. Fierro G. & R. Rodriguez L. (ANSM); Municipio de Muzquiz, 153.2 km NW of Muzquiz on Hwy 53 towards Boquilla del Carmen, P.M. Peterson & C.R. Annable 10600 (US); Municipio de Nadadores, Sierra de la Purisima, 3 km O de Lamadrid, carretera 30, J.A. ViUarreal Q. 3232, J. Valdes-Reyna. & M.A. Carranza P. (ANSM); Municipio de Ocampo, 22 mi W of Ocampo at Cuesta Zozaya, P.M. Peterson 8369 &}. Valdes-Reyna (MEXU, US); Municipio de Parras, 9 km S of Parras on Sierras Negras, R.L. Stanford 165, K. L. Retherford & R.D. Northcraft (MEXU); Sierra de Parras, 2.4 km al S de ej. Colorado, 8.8 km al E de Parras, C.P. Cowan 3605 (TAES); 3 mi N of Parras de la Fuente, E. Palmer 1348 (TAES); Municipio de Ramos Arizpe, Canada el Diente, Sierra de la Paila, J.A. ViUarreal Q. 5186 & M.A. Carranza P. (ANSM); Cation Loma Prieta, 12 km NE de Hipolito, camino al Valle Loma Prieta, J.A. ViUarreal Q. 3084, J. Elizondo, M.A. Carranza P. &A. Rodiguez G. (ANSM, CIIDIR); Puerto de San Lazaro, Sierra de La Gavia, J.A. ViUarreal Q. 3178, J. Valdes-Reyna & M.A. Carranza P. (ANSM); Sierra de la Paila (Lado Norte) Canada Becerros, J.A. ViUarreal Q. 5448, M.A. Car- ranza P. & L. Arce G. (ANSM); Sierra de la Paila, areas ca.nas a las minas La Casa Colorada & el Aguirreho, J.A. ViUarreal Q. 4504, 4557 & M.A. Carranza P. (ANSM, CIIDIR); Municipio de Saltillo, Saltillo, AS. Hitchcock 5624 (MEXU); Buenavista, ca. 6 km al S de Saltillo, E. Garcia s.n.(SLPM); J.A. De la Cruz (TAES); 2 km saliendo del libramiento por la brecha Saltillo-General Cepeda, J. Espinosa 120 (IBUG), J. Espinosa 122 (SLPM); alrededores de la Escuela de Agricultura "Antonio Narro", J.G. Garcia G. (IBUG); San Lorenzo canyon, 6 mi SE of Saltillo, M. Saldivar 557 (COCA); P. Lobato 11 (COCA); 5 km S of Saltillo, San Lorenzo Canyon, P.M. Peterson & C.R. Annable 10547 (US); 3.2 km E of Saltillo on hwy 57 towards Matehuala, San Luis Potosi, P.M. Peterson 10079, C.R. Annable &]. Valdes R. (ANSM, US); 4 km W of Saltillo por el camino Saltillo-General Cepeda, a la orilla del camino, J. Valdes-Reyna 1554, L.E. Rodriguez G. &R. VdsauezA. (ANSM); 8 mi W of Saltillo on route 40 and 1.5 mi W of Atenco, J. Valdes-Reyna 984 & T.L. Wendt (ANSM, TAES); Buenavista, 7 km S de Saltillo, carretera 54 Saltillo-Concepcion del Oro, Zacatecas, E. Garcia-Aguilera s.n. &* M.A. Gonzdlez-Galindo (ANSM); Cerro del Pueblo, W of Ciudad Saltillo, J. Valdes-Reyna 2047, M. Martinez M. & M.A. Carranza P. (ANSM); Entrada camino Fosa el Mamut, 2 km N del Ejido La Encantada, Sierra de Arteaga, J. Valdes-Reyna 1517a, L.E. Rodriguez G. (ANSM); Estacion Carneros, camino Torre de Microondas, 3 km O de la estacion, 30 km S de Saltillo, J. Valdes-Reyna 1501 Sr L.E. Rodriguez G. (ANSM), P.S. Hoge 297, M.E. Barhworth &]. Valdes-Reyna. (ANSM); 18 mi S of Saltillo on Mexico 54 and 1.4 mi W on road to microondas, just W of Estacion Carneros, P.M. Peterson 8411 &M.A. Carranza P. (ANSM, MEXU, US); Municipio de Sierra Mojada, vicinity of Santa Elena Mines, R. M. Stewart 284 (MEXU); Municipio de Torreon, S of Torreon; canyon between Jimulco and Juan Eugenio, P.M. Peterson 8471 cVJ. Valdes-Reyna (ANSM, MEXU, US); Sierra de Jimulco, 150 km E de La Mina de San Jose, J.A. ViUarreal Q. 5522, PA. Fryxell,]. Valdes-Reyna &? P.M. Peterson (ANSM). Nuevo Leon: Carretera a Trinidad China, J.A. Ochoa-Guillemar 1225 (COCA); 16 km NE of Sandia on road to La Ascension, P.M. Peterson 15832 &>J. Valdes-Reyna (ANSM, US); Municipio de Galeana, carretera Linares-San Roberto a medio km de la Galeana, M. Castillo 200 cy N. Bazaldu (COCA); bank of stream, V.H. Chase 7739 cy Mexican Biological Expedition of students of the University of Illinois (ANSM, US); Hacienda Peterson et al., Muhlenbergiinae from northeastern Mexico 993 Pablillo, M. Taylor-Edwards (MEXU); km 137 de la carretera 57, tramo Matetmala-Saltillo, al E del Cerro El Potosi,]. Garcia-? 500 (ANSM); 13.4 mi E hwy 57 on hwy 58 at crossing Rio Potosi, P.M. Peterson 13302 & M.S. Knowles (US); 10 mi S of San Jose de Raices, R. McVaugh 18239 (ENCB); La Becerra, G.S. Hinton 19793, 19888 (HINT, MEXU); Municipio de Iturbide, Bosque-escuela, Universidad Autonoma de Nuevo Leon, 12 km E de Iturbide, J. Cabral-Cordero 1081 (ANSM); Municipio de Monterrey, carretera Monterrey- Saltillo, N. Bazaldua B. 115 (COCA); Municipio de San Pedro Garza Garcia, carretera Villa de Garcia a Grutas (W of Monterrey), T. Tateoka, 1125 (US); Mu- nicipio de Santa Catarina, Ladera E del Cerro del Potosi, J. Garcia 500 (TAES); Municipio de Zaragoza, La Joya, Cuesta Blanca, 15 km de Aramberri rumbo a Zaragoza, J. Valdes-Reyna 2564, ].A. Villarreal M.A. Carranza P. (ENCB). Tamaulipas: Municipio de Palmillas, 55 mi SW of Ciudad Victoria on Mexico 101 towards San Luis Potosi, P.M. Peterson 8330 & RM. King (MEXU, US); Municipio de Palmillas, Ejido Palmillas, M.H. Cervera-Rosado 316 (COCA); Municipio de Victoria, 1 km S del Rancho El Novillo, 20 km O de Ciudad Victoria, F. Gonzalez-Medrano 3200 & E. Martinez (MEXU). 35. Muhlenbergia torreyi (Kunth) Hitchc. ex Bush, Amer. Midi. Naturalist 6:84. 1919. (Fig. 4, F-I). Agmstis torreyi Kunth, Enum. PI. 1:226. 1833. Agmstis caespitosa Torn, Ann. Lyceum Nat. Hist. New York 1(1):152-153. 1824, nom. illeg. horn., non Agrostis caespitosa (L.) Salisb. Prodr. Stirp. Chap. Allerton 25. 1796. TYPE: U.S.A. Prairies of the Missouri and Plate Rivers, E.James s.n. (HOLOTYPE: NY-327621!). Muhlenbergiagracillima Torn, Pacif. Railr. Rep. 4:155. 1857. Podosemumgracillimum (Torn) Bush, Amer. Midi. Naturalist 7:33. 1921. TYPE: U.S.A. TEXAS: Llano Estacado, 1853-1854, ].M. Bigelow s.n. (SYNTYPE: NY; ISOSYNTYPE: US fragm. ex NY!); Antelope Hills, 1853-1854, J.M. Bigelow s.n. (SYNTYPE: NY; ISOSYNTYPE: US fragm. ex NY!). Caespitose perennials. Culms 10-40(-50) cm tall, decumbent at base, hispidulous below the nodes, usually no culm nodes exposed above the tightly clustered leafy base, the leafy portion not reaching more than 1/5 the plant height; internodes mostly scabrous to glabrous. Leaf sheaths 0.1-2.5(-3.2) cm long, shorter than the internodes, scaberulous to glabrous, margins hyaline; ligules 2-5(-7) mm long, hyaline, often splitting down the middle and appearing as auricles, apex acuminate, lacerate, margins entire; blades l-3(-5) cm, long, 0.3-0.9 mm wide, tightly involute or folded, arcuate, somewhat sharp pointed, scaberulous. Panicles 7-21 cm long, 3-15 cm wide, open, diffuse; primary branches 1-8 cm long, ascending to stiffly spreading at maturity 30-90 from the rachises; pedicels 1-8 mm long, erect, sometimes appressed to the branches. Spikelets 2-3.5 mm long, erect; glumes 1.3-2.5 mm long, about equal in length, 1-nerved, unawned, mu- cronate, or awned, scaberulous towards apex, apex acute to acuminate, minutely erose, the mucro or awn up to 1.1 mm long; lemmas 2-3.2(-3.5) mm long, narrow elliptic to lanceolate, mucronate or awned, ap- pressed pubescent on the margins and midvein on the proximal Vi to %, scabrous above, apex acuminate, the mucro or awn 0.5-4 mm long; paleas 2-3.2(-3.5) mm long, narrow elliptic, sparsely pubescent between the nerves, apex acuminate sometimes with two mucros, the mucros up to 0.2 mm long; anthers 1.2-2.1 mm long, greenish. Caryopses 1.7-2.0 mm long, fusiform, brownish. 2n = 20, 21. Phenology.?Flowering May through October. Distribution and habitat.?Muhlenbergia torreyi grows in desert grasslands, sandy mesas, calcareous rock outcrops, rocky slopes, and open woodlands with Prosopis spp., Yucca sp., Larrea tridentata, Lycium spp., Parthenium argentatum, Agave lecheguilla, Artemisia tridentata, Psilostrophe sp., Ceratoides lanata, Bouteloua gracilisjuniperus osteosperma, and Pinus edulis; 1000-2450 m; southeastern Arizona to eastern Colorado, and extreme southeastern Wyoming, western Kansas to western Texas, New Mexico, U.S.A., northern Mexico in Sonora and Chihuahua, and disjunct in northwestern Argentina and Bolivia. Specimens examined. MEXICO. Coahuila: 35.4 km W of Ocampo at Cuesta Zozaya, P.M. Peterson 8364 &]. Valdes-Reyna (US); Municipio de Arteaga, 18 mi E of Saltillo, J.R. Reeder 5002 &> C.G. Reeder (US); Municipio de Saltillo, Rancho Demostrativo "Los Angeles" 48 km al S de Saltillo, L.H. Harvey 8738 (ENCB). Nuevo Leon: Municipio de Galeana, Rancho Aquililla, G.B. Hinton 27026, 27073 (HINT). 36. Muhlenbergia utilis (Torr.) Hitchc, J. Wash. Acad. Sci. 23(10):453. 1933. (Fig. 20, E-I). Vii/autifoTorr., Pacif. Railr. Rep. 5(2):365-366. 1857. Sporobolus utilis (Torr.) Scribn., Bull. Div. AgrostoL, U.S.D.A. 17:171, f. 467. 1899. TYPE: U.S.A. CALIFORNIA: Lost Mountain Spring, from Tejon to the Lost Hills, in stony places, W.P. Blake s.n. (HOLOTYPE: NY'; ISOTYPES: GH, MO!, US fragm. ex NY!). Perennials with slender, scaly rhizomes. Culms 7-30 cm tall, erect to decumbent, older plants trailing, up to 1 m long, minutely pubescent to glabrous below the nodes; internodes mostly smooth to lightly nodulose- roughened. Leaf sheaths 0.3-2.4 cm long, shorter or longer than the internodes, glabrous, margins hyaline; ligules 0.2-0.8 mm long, membranous, decurrent, apex truncate; blades 0.5-4.7 cm long, 0.2-1.8 mm wide, 994 Journal of the Botanical Research Institute of Texas 1(2) involute, sometimes flat, straight or arcuate-spreading, blades often at right angles to culm, mostly glabrous below and hirsutulous above. Panicles 1-5 cm long, 0.1-0.4 cm wide, narrow, contracted, interrupted between each branch, partially included in the upper sheaths; primary branches 0.2-1.2 cm long, appressed, rarely ascending up to 30? from the rachises; rachises usually visible between the branches; pedicels 0.1?1.1 mm long, glabrous. Spikelets 1.4-2.4 mm long, erect; glumes 0.5-1.4 mm long, 1/3 to Vi as long as the lemma, subequal, unawned, glabrous, usually 1-nerved, occasionally 2- or 3-nerved, yellowish to light green, apex acute; lemmas 1.3-2.4 mm long, lanceolate, unawned, glabrous or with minute appressed pubescence along the margins and base, the hairs about 0.1 mm long, green or purplish, apex acute; paleas 1-2 mm long, lanceolate, glabrous, apex acute; anthers 0.7-1.4 mm long, yellow to purplish. Caryopses 0.7-1.2 mm long, ellipsoid to ovoid, brown. In = 20. Phenology.?Flowering July to December. Distribution and habitat.?Muhlenbergia utilis occurs in wet soils along streams, ponds, depressions in grasslands, and alkaline or gypsiferous plains associated with Quercus spp., Q. agrijolia, Acacia sp., Prosopis sp., Larrea tridentata, Pinus spp., and Cupressus sp.; 200-2500 m; southwestern California, southern Nevada, southern Arizona, southcentral Texas, U.S.A. to Mexico in Estados Chihuahua, Sonora, Durango, Guanajuato, Hidalgo, Jalisco, Zacatecas, Mexico, Distrito Federal, Michoacan, Queretaro, Puebla, Veracruz, and Chiapis to Costa Rica. Specimens examined. MEXICO. Coahuila: Municipio de Arteaga, Rancho el Chorro, carretera al Tunal, 3 km E de la desviacion al Tunal, sobre la carretera de Saltillo-Matehuala, San Luis Potosi, J. Espinosa-Aburto 170. (ANSM, SLPM); Ojo Caliente ca. 50 km SW of Monterrey, F.A. Barkley 16281 (US); Municipio de Parras, 3 mi N of Parras de la Fuente, F.W. Gould 11554 (TAES); Municipio de Saltillo, Saltillo, A.S. Hitchcock 1378 (TAES), A.S. Hitchcock 5652 (US); 2 mi S of San Lorenzo, ].R. Render 4830 & C.G. Reeder (ENCB, MEXU); 3 mi N of Saltillo on Piedras Negras Hwy, F.W. Gould 11212 (TAES). Nuevo Leon: Municipio de Galeana, Galeana, J.A. Ochoa-Guillemar 1003 (COCA); along hwy 57, 32 km N of San Roberto, 18 km S of San Rafael, C.W. Morden 522, 523, S.L. Hatch &?]. Valdes-Reyna (ANSM, TAES); 4 mi SE of Galeana, ].R. Reeder 4986 & C.G. Reeder (US); 3 mi E of jet of hwy 60 & 57, C.W. Morden 519, S.L. Hatch &?]. Valdes- Reyna (ANSM, SLPM); km 63.6 carretera Galeana-San Roberto, I. Cabral-Cordero 1085 (ANSM, ENCB); Municipio de Linares, Bano de San Ignacio, 22 km NE de Linares, I. Cabral-Cordero 771 (ANSM); 12.9 km E of Los Lirios on road to Laguna de Sanchez, 60 km SE of Saltillo, P.M. Peterson 6259 & C.R. Annable (US). 37. Muhlenbergia villiflora Hitchc. var. villiflora, N. Amer. Fl. 17(6):470. 1935. (Fig. 16, F-I). Vilfapubes- cens E. Fourn., Mexic. PL 2:102. 1886, non Muhlenbergia pubescens (Kunth) Hitchc. TYPE: MEXICO. TAMAULIPAS: inter Michiguana et Tanquecillos, Canon de las Minas et Victoria, W. Karwinsky 1012 (HOLOTYPE: P!; ISOTYPE: US fragm. ex P!). Perennials with scaly rhizomes. Culms 4-20(-27) cm tall, to 2 mm thick, erect, wiry, smooth to nodulose roughened below the nodes; internodes smooth or nodulose. Leaf sheaths 5-15 cm long, shorter than the internodes, about Vi the length of the internodes, glabrous to nodulose roughened, margins hyaline; ligules 0.4-1.5 mm long, membranous, decurrent, apex acute, erose and toothed; blades 0.7-2 cm long, 0.2-1.2 mm wide, involute, arcuate-spreading, glabrous below and hirsutulous above. Panicles 1-5 cm long, 0.1-0.5 cm wide, narrow, contracted, loosely-flowered, usually on an exserted peduncle; primary branches 0.2-1.1 cm long, appressed, ascending; pedicels 0.1-0.8(-1.2) mm long, shorter than the spikelets, minutely se- tose. Spikelets 1.4-2.4 mm long; glumes 0.6-1.8 mm long, equal, unawned, glabrous, usually 1-nerved, occasionally 2- or 3-nerved, V2 to 2/3 the length of the floret, green or purple, apex acute; lemmas 1.4-2.4 mm long, lanceolate, indistinctly 3-nerved, mucronate or not, green or purplish, densely villous along the midvein and margins on the proximal 4/5, the hairs 0.4-1 mm long, apex acute, the mucro 0.1-0.6 mm long; paleas 1.2-2.1 mm long, lanceolate, densely villous between the nerves on the proximal 2/3, apex acute; anthers 0.8-1.5 mm long, yellow, dark green, or purple. Caryopses 1-1.4 mm long, ellipsoid to fusiform, dark brown. In = 20, 22. Phenology.?Flowering July through October. Distribution and habitat.?Muhlenbergia villiflora occurs in openings primarily on alkaline soils derived from gypsum, rocky flats, and desert grasslands usually in small, isolated populations associated with Larrea tridentata, Juniperus monosperma, Flaveria sp., Isocoma sp., Sarcobatus vermiculatus, Parthenium sp., Prosopis sp., Dasyochloa pulchella, Enneapogon desvauxii, Sporoblolus airoides, Opuntia imbricata, Buddleja sp., Muhlenbergia Peterson et al., Muhlenbergiinae from northeastern Mexico 995 tenuifolia, Erioneuron avenaceum, and Bouteloua spp.; 1500-2100 m. In Mexico, M. villijlora var. villijlora also occurs in Chihuahua, Durango, Zacatecas, and San Luis Potosi. Comments.?Plants that occur in New Mexico and Texas, U.S.A. belong to M. villijlora var. villosa (Swal- len) Morden. This variety differs from var. villijlora by having longer spikelets (1.8-2.5 mm versus 1.4-2.3 mm long) and a preference for alkaline to calcareous, rather than gypsiferous soils. Specimens examined. MEXICO. Coahuila: Municipio de Dr. Arroyo, Ejido El Jarro, J. Garza 192 cv M. Castillo (COCA); Municipio de Ocampo, Rancho Experimental Santa Teresa de La Rueda, 87 km NE de Ocampo, brecha Ocampo-Boquillas del Carmen, M.T. Ruiz-de Leon s.n., M.A. Carranza P. & M. Vdsquez R. (ANSM); Municipio de Saltillo, 28.3 mi S de Saltillo on Hwy 54 to Concepcion del Oro, Za- catecas PM. Peterson 10029, C.R. Annable &]. Valdes-Reyna (ANSM, US); 53.2 km S of Saltillo on MEX Hwy 54 and 28.5 km E on road to La Ventura, P.M. Peterson 10040, C.R. Annable &>]. Valdes-Reyna (US); 50 km S de Saltillo, carretera 54 a Concepcion del Oro, Zacatecas, J. Valdes-Reyna 2059,].A. VillarrealQ. Sr M.A. Carranza P. (ANSM); 6 mi N of La Ventura, l.M. Johnston 7642 (US); 10 mi E of Fraile, road from Saltillo to Concepcion del Oro, I.M.Johnston 7305 (US); Estacion Carneros, carretera a Zacatecas 30 km S de Saltillo, M.A. Carranza P. 518 & P.M. Peterson (ANSM); La Ventura, 80 km S de Saltillo, J.A. Villarreal Q. 1992, 3501, M.A. Carranza P.