TAXONOMIC STUDY OF SUBGENUS PODOSEMUM AND SECTION EPICAMPES OF MUHLENBERGIA (GRAMINEAE) By TnoMAs R. SODERSTROM Introduction Within the genus Muhlenbergia (Gramineae) is a group of tall, rather robust perennials that some botanists have treated as a distinct genus, Epicampes. Since Presl (1830) proposed Epicampes, many species have been added. All are found in tbe Western Hemisphere, the majority occurring in northern and central Mexico, the center of distribution. The characters originally employed to delimit Epicampes have been interpreted by botanists in different ways. Some have placed considerable emphasis on the dorsal position of the awn of the lemma, while others have regarded the relatively long glumes of the spikelet as particularly characteristic. Another feature of value is tbe com­ pressed-keeled nature of the basal sheaths. No one character has been found to distinguish all species of Epicampes from all other genera. Authors who have described species in the group have had different concepts of the genus, to the extent that Epicampes has never been clearly circumscribed. Unfortunately, no recent author has listed the species considered to comprise the genus Epicampes, and not only is the generic status and affinities of the group a problem, there is also no general agreement regarding the number of species. Traditionally, the classification of grasses has been based on characters of gross morphology, with special reference to the structure of the spikelet. In such a classification Epicampes has been treated as a member of the tribe Agrostideae, which includes grasses with single-flowered spikelets, with close affinities to such genera as Agrostis and Dinna. Starting before the I,urn of the century, but more particularly within the last decade, studies of features other than gross morphology have shed much light on the true relationsbips within the Gramineae. These studies have included investigation of the structure of the grass embryo, lodicules, chromosomes, and the anatomy of the leaf and epidermis. The results of these investigations are correlated remark- 75 76 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM ably and demonstmte that in many cases the characters of the spikelet and other features of gross morphology are not reliable indexes to the natural relationships of grasses. These studies for the most part have dealt with representative species of genera, in an attempt to find their natural affinities within the grnss family. Relatively little effort hus been made to utilize these studies Itt the infrageneric level to clarify relationships among the species within a single genus. The first phase of the present study was to determine the relation­ ship of the Epicampes group at the genus level, and studies of the embryo, lodicules, and leaf anatomy and epidermis were useful in tbis regard. Tbe results of tbese investigations provide strung evi­ dence tbat Epieampes is not related to such genera as Agrostis and Oinna of tbe Agrostideae but rat.her to grasses of the "cbloridoid" alliance, wbicb includes many grasses traditionally plnced within tbe tribe Chlorideae. The second phase was a taxonomic su rvey of tbe species belonging tu the Epicampes group. Field studies were made in Mexico in 1959 and 1960 and herbarium specimens examined included the majority of type specimens or fragments of types of tbe species involved. In addition to the large series of specimens studied at Yale Uni­ versity (YU) and the U.S. National Herbarium (US), collections were borrowed from the following herbaria: University of Arizona (ARIZ); California Academy of Sciences (CAS); Escuela N acional de Agricultura, Chapingo, Estado de Mexico (CHAP); Stanford University (DS); Field Museum of Natural History (F); Gray Herbarium of Harvard University (GH); University of Illinois (ILL); Instituto Politecnico Nacional, Mexico, D.F. (IPN); Texas Re­ search Foundation (LL); Universidad Nncional de Mexico (MEXU); University of Miehig.m (MICH); Missouri Botanical Garden (MO); New York Botanical Garden (NY); Pomona College (POM); Natur­ historiska Riksmuseum, Stockholm (S); Sonthern Methodist Uni­ versity (SMU); A.&M. College of Texas (TAES); University of Texas (TEX); University of California (VC); University of New Mexico (UNM); and Instituto Botilnico, Ministerio de Agricultura y Crill, Caracas (VEN); The abbreviations of herbarium names are those of Lanjouw and Stafleu (Index Herbariorum, ed. 5, 1964) except for CHAP and IPN which are the autbor's. Tbis paper is based on a doctoral dissertation prepared at Yale University under the guidance of Dr. John R. Reeder, whose advice, encouragement, and perseverance will always be an inspiration to me. To his wife, Charlotte Goodding Reeder, my sincere appreci­ ation for her assistance during the entire study at Yale. Tho work was completed at the U.S. National Herbarium and I am most grateful to Dr. Jason R. Swallen for his advice, assistance, and generosity in SODERSTROM-PODOSEMUM AND EPICAMPES 77 many ways. Mrs. Susan Colby McKanna of the Smitbsonian deserves very special thanks for giving so much of ber time to type, proofread, and carry out many other necessary tasks connected with the final writing. Of my colleagues at the Smithsonian, a word of appre­ ciation to Drs. William L. Stern, Mason E. Hale, Floyd A. McClure, and Mr. Conrad V. Morton, eacb of whom has been of special belp. To Dr. Frank W. Gould, Texas A & M University, who read tbe manuscript before its final revision, I express my sincere thanks for his constructive criticisms. Historical COll8iderations Tbe description of the genus Epicampes by Jan S. Presl (1830) was based on a single collection from southern Mexico. In K. B. Pres!'s introduction is the statement (translated): "In the month of November Tbaddaeus Haenke went alone to the capital city of Mexico, and returned in December to Acapulco." It was on this trip in 1791 tbat Haenke collected the type specimen of Epicampes. Altbougb no locality otber tban "Mexico" is given, Pres!'s description and illustration of tbe specimen resemble most closely other specimens of Epicampes from tbe central Mexican plateau. Furthermore, Haenke's specimen was probably collected higher on the plateau in the state of Morelos or Mexico, rather than in the lower and more tropical elevations of Guerrero, of which Acapulco is the main port of entry on tbe Pacific. Tbe name Epicampes may have been derived from the classical Greek word "kampes," an adjective meaning Hcurved." It is unclear why Presl chose a word witb sucb a meaning as a name for tbis genus. Unfortunately, be gives no indication of its etymology in the original description. The type species, Epicampes strictus Presl (Muhlenbergia robusta [Fourn.] Hitcbc.), is widely distributed in tbe higber elevations from the state of Jalisco southward into Central America. His description of the genus, translated from tbe Latin, follows: Panicle contracted, in the form of a spike, with alternate solitary branches. Glumes two, ovate, convex, nerveless, subequal, obtuse, entire. Floret a little longer than the glumes. Glumes two, convex, ovate, the lemma sur~ rounding the palea at its base, entire, with the median nerve extending into a. straight awn from beneath the apex, the palea 2-nerved, very obtuse, en­ closing the genitalia. Stamens 3. Ovary ovate, emarginate at apex. Styl~ 2. Stigmaa divided into dense branchlets. Lodicul~ ... caryopsis .... It seems to differ enough from Agrostis by the entire lemma and palea, with a straight awn neither twisted nor plicate, from Apera by the awned lemma. To this genus belong also Agr03lu pubescens and A. lanata. Of the several features that Presl enumerated for Fpicampes, tbe nerveless condition of tbe glumes and tbe awn rising from i ust be- 78 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM low the tip of the lemma have been regarded by subsequent authors as important diagnostic characters for the genus. As originally proposed, Epieampes comprised three species. Be­ sides E. strict us, Presl included Agrostis lanata H. J3. K. and A. pubesccns H. B. K. These species had been described by Humboldt, Bonpland, and Kunth (1815) from specimens collected by Humboldt in the stlLte of Guanajuato, north of where IIaenke had collected. Three other species described in the same work, Orypsis macroura, C. phleoides, and Podosaemum distichophyllum, were Inter included in Epicampes by other workers. Thus, the species assigned to Epicampes had been described under the genera, Agrostis, Orypsis, and Podosaemllm. Kunth, who originally named the two Humboldt collections from Guanajuato as species of Agrostis, later accepted Pres!'s contention that they belonged to Epicampes. In 1833, Kunth's Aurostographia was puhlished in Germany, where Epicampes waS included in the Agrostideae, a trihe estahlished hy Kunth in 1815. Incorporated in this tribe were all grasses characterized by single-flowered spikelets: V. Agrostidcac. Spikcict.s single-flowered, rarely with a rudimentary subulate flower above the other. Glumes 2, lemma and palea, membrana­ ceous-herbaceous j lower often awned. Stigmas mostly spreading. Through lIfuMenbergia affinities with Stipa. Although recent research has demonstrated the unnaturalness of the Agrostideae as interpreted hy Kunth, many contemporary taxono­ mists still recognize the trihe and place in it Muhlenberuia, including the Epicampes group. Kunth's description of Epicampes was similar to Presl's. He placed the genus hetween Cinna L. and Sporobollls Brown, men­ tioning that it "differs from Oinna principally by its convex, non­ keeled glumes." The genus 1I1uhlenbergia, in which many recent nuthors have incorporated Epicampes, evidently was not considered by Kunth to be as closely allied, for he separates the two hy several genera. Trinius (1841) recognized Epicampes essentially as Presl and Kunth had hefore him but descrihed the species in more detai! and added one new species, E. Uracilis (Muhlenberuia lindheimeri Hitchc.). He descrihed the glumes as I-nerved, in contrast to Presl's and Kunth's statements that the glumes are nerveless. Yet, in his description of E. strictus and E. pubeseens, Trinius noted that the glumes are nerve­ less. The new species Trinius descrihed was from Texas, the first of the group from the United States. Unti! 1874 Epieampes was treated as comprising only four species, E. strictu8, E. lanatus, E. pubeseens, and E. gracilis, all with a hahit and panicle similar to the first species that Presl described, and as a SODERSTROM-PODOSEMUM AND EPICAMPES 79 genus ranging from southwestern United States (Texas) to southern Mexico. This concept of Epicampes was expanded by Grisebach (1874) in a description and discussion of the collections of Argentine plants of Professor Lorentz. In this work Grisebach described a new species, E. eoeruleus (Muhlenbergia angustata [Presl] Kunth), with spikelike panicles, I-nerved, awn-tipped glumes, and a long acute ligule. At the same time he transferred two other species with spikelike panicles to Epicampes: Oinna phleaides Kunth (based on Orypsis phleoides II. B. K.) and O. stricta Kunth (based on Orypsis stneta H. B. K.). By incorporating these species from Argentina into Epicampes, the range of the genus was considerably extended. George Bentham (1881) in the first really critical comments con­ cerning the generic limits of Epicampes recognized four subtribes within the Agrostideae, one, the Euagrosteae, included Epicampes. About 16 genera comprised this sub tribe, of which he concluded: .. . the general character is a dorsal usually twisted awn on the flowering glume, the grain neither so closely enveloped in the fruiting glume as in Stipeae, DOf so readily exposed as in Sporoboleae, and the spikelets usually small, loosely paniculate, very rarely condensed into a head as in Phleoideae; but there are exceptions to every Olle of these characters, and the limits of the larger genera arc so vague as to render this portion of the genera of Gramineac the least satisfactory of the whole series. Bentham stated that Epicampes was composed of "about 16 species," 1 but that this number was possibly too large and most probably reducible by one-third, and that it "is a genus most embar­ rassing to the systematist; for it seems to connect Muhlenbergia and Sporobolus with Agrostis." One of the characteristics he regarded as distinctive of Epicampes was the long, narrow, dense panicle composed of numerous small spikelets. He differentiated Epicampes from Muhlenbergia by the llwns on the lemmas which, when present in the former, are short llnd not quite terminal, wbile in the latter are longer and terminal. The dorsal position of the aWll was one of the chief distinguishing features recognized by Presl in establishing the genus. Bentham distinguished Epicampes from Sporobolus by the fact that in the former the glumes are thinner and more membranous than the lemma and palea but in the latter they are thicker and less mem­ branous. Bentham admitted his unfamiliarity with many of the 1 A survey of the literature reveals only 9 published species of Epicampes up to and including those described in Bentham's paper. For hiB estimate of 16 species, Bentham doubtless relied on Fournier's treatment of the group in Mexi­ canas Plantas. Although the title page was not printed until 1886, Fournier had Bcnt copies to several botanists as early as 1880. In the first part of his ffNotes" (p. 20) Bentham stated that Fournier had supplied him with a copy, remarking, III feel bound, insofar as I am concerned, to treat it as having already taken date." 80 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM published species, adding that, "a further study may require consider­ e.ble modification of the generic charaeler and limits." Following the example of Grisebach, Bentham included in Epi­ campes additional species with spikelike panicles. He transferred Fournier's Orypsinna and Kunth's Oinna macroura and O. stricta to Epicampes macroura (Muhlenbergia macroura [H.B.IL] Hitchc.). Oinna macroura Thurber was placed in Epicampes to become Epi­ campes rigens Benth. (Muhlenbergia rigens [Benth.] Hitchc.), a species closely related to E. macroura. The genus Bauchea Fourn., repre­ sented by a single Mexican species, B. karwinskyi, which Bentham had not seen, was also considered by him to be an Epicampes (although later synonymized with Sporobo/us wrightii Munro ex Scribn.). In Bentham and Hooker (1883) 2 four subtrihes of the tribe Agros­ tideae are listed, with the genera enumerated under each. The four suhtribes are: Stipeae, Phleoideae, Sporoboleae, and Ellllgrosteae. Epicampes was placed within Euagrosteae and Muhlenbergia in Stipeae. Sporobolus, considered by some as closely allied to Epicampes, was the basis of subtribe Sporoboleae. Of the four subtribes listed, the Sporoboleae, containing the single genus Sporobolus, is distinctive in that the grain is not a true caryopsis but rather the seed is loose from the ovary wall (pericarp). Furthermore, the fruit is loosely enclosed within the lemma and palea and drops out easily; for this reason the popular name" dropseed" has been applied to the genus. The chief distinction of the Euagros­ teae appears to be the position of the awn on the lemma, dorsal in some cases, "rarely arranged sub terminally to a mucro, or variously awned" (Bentham, 1883). However, grasses with awned lemmas are also found in the Stipeae and Sporoboleae. The position of the awn on the lemma in the Euagrosteae does not easily separate this subtribe, and the Stipeae and Euagrosteae sbow no distinctive features to separate them clearly. According to Bentham's description of 1I1uhlenbergia (Stipeae), the major character to differentiate this genus from Epicampes (Euagros­ teae) was the relatively small size of the glumes as compared with the lemma and palea. Yet, even here species are included with the glumes subequal to the floret. The awn of the lemma in Epicampes was stated as minute and subterminal, although in Muhlenbergia the awn was described only as "rarely obsolete." There was no reference to its position on the lemma. Although Bentham gave these con­ trasting characters for the two genera, none was distinctive enough to separate all species of Epicampes from all species of Muhlenbergia. 3 The treatment of Gramincae in Genera Plantarurn (1883) was produced by Bentham whose IINotes on the Gramincac" (1881) was based on observations made during its preparation. SODERSTROM-PODOSEMUM AND EPICAMPES 81 Following the lead of previous authors, Vasey (1885) placed Epicampes in the Agrostideae. Employing the system of Bentham and Hooker, he included Muhlenbergia in the subtribe Stipeae and Epicampes in the subtribe Euagrosteae. According to Vasey's interpretation, the only essential character that differentiated the two subtribes was the position of the awn on the lemma. He said of the Stipeae, "beard of the flowering glume terminal," and of the Euagrosteae, "flowering glume usually with a more or less twisted dorsal awn; rarely mucronate or awnless." Like Bentham and Hooker, he included the genera Agrostis, Polypogon, Arctagrostis, and Oinna in the same group of Euagrosteae with Epieampes. In his description of Epicampes, Vasey recognized three species: E. distichophyllus Vasey, E. macroura Benth., and E. rigens Benth. He stated that the spikelets of Epicampes are much like Sporobolus but contracted in a long, narrow, and dense panicle. He added, ... Outer glumes somewhat unequal, membranaceous, convex on the back, scarcely keeled, obtuse, three-nerved; flowering glume mostly equalling the outer ones, sometimes three to five nerved, entire or sometimes awned from the apex; palet hyaline, about equalling the flowering giume, two nerved or two-keeled. Vasey seems to have considered long dense panicles and glumes a little longer than the lemma as the important features of Epicampes. He erred, however, in stating that the glumes are 3-nerved; previous agrostologists had emphasized the nerveless or I-nerved condition of the glumes in species of this group. He also said that the lemmas ("flowering glumes") are entire or awned from the apex, but did not recognize the dorsal position of the awn as a diagnostic feature. Nevertheless, in E. distichophyllus Vasey CM. emersleyi Vasey) the awn is clearly dorsal, or subterminal, rather than terminal. Hemsley received a copy of Fournier's manuscript of Mexicanas Plantas before its publication and drew upon it in Biologia Centrali­ Americana (1885). In the introduction, Hemsley remarked, "with regard to many of the new species described by Fournier which we have had an opportunity of examining, we consider them as varieties undeserving of distinctive names even." Hemsley's treatment in­ cluded many of Fournier's species, and he comments that of the 16 species proposed up to that time, several were not distinguishable as such. The genus Epicampes followed Sporobolus in his treatment, in accordance with contemporary taxonomic opinion. Roth Hemsley's and Fournier's works merely contain listings of genera and species, with a brief description of each species but no descriptions of the genera. Fournier and Hemsley followed the treatment of Gramineae as proposed earlier by Bentham (1881). 82 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM Hackel (1890) in The True Grasses (a translation by F. Lamson Scribner and E. Southworth) also followed Bentham and placed Epicampes in the Euagrosteae. Hackel mentioned 12 species in con­ trast to l.he 13 recognized by Fournier. Vasey (1892) listed two species of Epicampes, E. ligula/us, described as new, and E. rigens Benth. IMuhlenbergia rigens (Benth.] Hitchc.). One species that Vasey included in the genus Muhlenbergia, M. emersleyi Vasey,' was later transferred to Epicampes by A. S. Hitch­ cock. Vasey's concept of the generic limits of Epicampes did not fully coincide with the geneml established concept, for he certainly would have included M. emersleyi within Epicampes if he had been familiar with the chamcters used to delimit the genus. Except for the glabrous lemmas of E.ligula/us and E. rigens, no characters would exclude tbem from bis concept of Muhlenbergia-but, even tben, under Mulden­ bergia be remarked that the flowering glumes, or lemmas, are "fre­ quently" pubescent below. Although Vasey recognized Muhlenbergia and Epicampes, he failed to select good characters to distinguish these two genera. A key to nine species of Epicampes was given by Beal in 1896. In his discussion, Beal remarked that all species of Epicampes seemed near Auros/is, but some closest to Oinna, others to Muhlenbergia, and yet others to Sporobolus. He stated: . . . the chief genoral feature is the long narrow dense panicle with very numerous rather smnll apikelets, the awn of the floral glumc, when it exists, much smaller than in Muhlenber(Jia and often not qllitc terminal; the llnawned species nre distinguished from Sporobolu8 by the fruiting glumc and grain which are nearly those of Agrostis. The notes on Epicampes by MarClls Jones (1912) point up the confusion that had developed in establishing the boundaries (or Epwampes. Jones' conclusions, based solely on morphological observations, Rre corroborated to a large extent by anatomical studies made by the present author. Jones considered as the most important character of Epicampes the specialized awn of the lemma that arises from just helow the tip, that is, dorsally or from an emarginate tip. Although JOlles erred in associating Bealia mexicana Scribn. (Muhlenbergia biloba Hitchc.), M. argentea Vusey, and M. clomena Trin. with Epicampes, he did recognize that certain other species associated with Epicampes belong to It separRte group. This group includes the species with spikelike panicles, coarse rihbed leaves, and firm Iigules. Jones followed Fournier in assigning such species to the genus Orypsinna. He also included Epicampes macroura Bellth. , Vasey also listed another Muhlenbergia, M . dislichophylla Kunth . The speci­ men referred to, however, was !If. emersieyi and is not to be confused with Af. di$tichophylla of Mexico and Guatemala.. SODERSTROM-PODOSEMUM AND EPICAMPES 83 in the genus, as Fournier had done, and further considered E. rigens Benth. to be a member. Fournier originally established the genus Orypsinna based in part upon Orypsi., H. B. K. and in part on Cinna Kunth (not L.), and in­ cluded species with I-flowered spikelets and dense spikelike panicles. Bentham chose to reduce Orypsinna to Epicampes, but Jones accepted Fournier's genus and did not recognize those species with spikelike panicles as belonging to Epicampes. Hitchcock in 1914 and in earlier works recognized the genus Epicampes, although later he united it with Muhlenbergia. His description of Muhlenbergia indicated that "it grades on the one hand into Sporobolus, from which it differs in having an awned or mucronate lemma, and on the other into Epicampes, from which it differs in having a relatively firmer lemma." Bentham used the firm lemma in Epicampes as a character in contrast with the thinner lemmas of Sporobolus. Hitchcock (1920) based his description of Epicampes on the characters of the equal glumes, the awn of the lemma which, when present, characteristically rises from just below the tip, the caespitose, perennial habit of the plants, and the open, narrow, or spikelike panicles. Hitchcock regarded Crypsinna as a synonym of Epicampes. He also transferred Muhlenbergia emersleyi Vasey and M. vaseyana Scribn. (M. distichophylla sensu Vasey) to Epicampes, bringing the number of species to 15. Bews (1929) regarded the texture of the lemmas as a significant character in differentiating genera within the Agrostideae. Under the first category of the tribe, "lemma usually hyaline or mem­ branaceous at maturity, at least as delicate as the glumes, or more so," he included Sporobolus, Agrostis, and Epicampes, in addition to many other genera. Muhlenbergia is found under the second category, "lemma indurated at maturity, or at least firmer than the glumes." Bews listed the same species of Epicampes that Hitchcock had listed in his 1920 publication. A significant change was made in the disposition of Epicampes by Hitchcock in 1934. In transferring Epicampes ligulatus Scribn. to Muhlenbergia (M. longiligula Hitchc.), he commented: .. . the character which I have used to differentiate the two, the awn from the back of the lemma, just below the apex in Epicampcs and from the tip in Muhlenbergia, has several exceptions in the latter genus. Since it is impos­ sible to find a clear line of division to separate the genera, I am uniting Epicampcs with Muhlenbergia. Hitchcock (1935) contributed a complete treatment of all North American species of Muhlenbergia, in which he transferred all species 84 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM of Epicampes to MuhlenbergW,. His disposition of the group has been followed subsequently by most American ta.~onomists. The inclusion of Epicampes within Muhlenberyia, however, has not been universally accepted. The most recent system of classifi­ cation of the grasses treating all known genera was that of Robert Pilger in 1954, with a more complete fOlro in 1956. Pilger placed Epicampes in the tribe Eragrosteae which he divided into six sub­ tribes. Sub tribe 5, Sporobolinae, included not ollly Sporobolus, but also Epicampes, Orypsis, Heleochloa, Urochondra, Sphaerocaryum, and Blepharoneuron. Muhlenbergia, excluding tbe Epicampes species, formed subtribe 6, the Muhlenbergiinae. A translation of tbe section of bis key separating tbe Sporobolinae and Muhlenbergiinae follows: J. Spikelet! often broad; glumes thin; lemmas awnlcss; cilryopsis more or less wide ... ................... . Subtribe 5. SPOROBOLINAE II. Spikelets small; glumcs firm; glumes often more or less short.cr than the lemmas, these often more or less long-awned; caryopsi8 smnll, cylindrical. 8ubtribc 6. M UHLENBERGJlNAE Pilger did not enumerate the species he recognized under Epicampes, but most of the species traditionally regarded as members of this genus possess awned lemmas. The type specimen of tbe genus, E. slmtus Presl, is figured witb short-awned lemmas. Moreover, since Presl established Epicampes the position of the all'll on tho lemmas has been used as a generic character of great importance. It is therefore surprising that Pilger should have placed Epicampes in a tribe composed of members with awnless lemmas. Hubbard, in his treatment of Gramineae (1959, rev.), recognized Epicampes. Sporobolus, often regarded as sbowing a relationship with Epicampes, was placed in the tribe Sporoboleae, along with Blepharoneuron. MuhlenbergW, and Epicampe." in flddition to Ayros­ tis, Calamagro8lis, Lagurus, Gastridium, Triplachne, Echinopogon, Dichelachne, Polypogon, Ph/cum, and Alopecuru8, among others, con­ stituwd the tribe Agrosteae. It is apparent thnt Epicampes never has been clearly nnderstood. Different characters hnve been used by botanists to delineate the genus and few of their descriptions fully agree. Tbe Ameri<:an, A. S. Hitchcock, incorporated the species of Epicampes into the genus Muhlenbergia, and since then most Americnn taxonomists have ac­ cepted his trcntment. , Leaf Anatomy and Epidermis The first suggestion that the anatomy of grass lenves might be useful in systematics was made by Duval-Jouve (1875) who found differences in tbe distribution of bullifonll cells among species of different tribes. Additional anatomical differences were pointed out by Scbwendener (1890). In 1898, Pee-Laby recognized five groups SODERSTROM-PODOSEMUM AND EPICAMPES 85 based on characters of leaf anatomy, although these groups were based on poor characters (Brown, 1958). Avdulov's system (1931) incorpo­ rated tbe characters of leaf anatomy and chromosome size and number. Prat (1936) found that characters of the leaf epidmmis are useful from a systematic standpoint and tbat the results based on these characters correlate well with those derived from a study of the internal anatomy. He referred to Avdulov's major groups as "panicoid" and "festucoid" and segregated the former into two subgroups, the "eupanicoid" and "chloridoid." Brown (1958), in a study of the leaf anatomy of 101 species in 72 genera, found that six groups can be delimited by characters of the internal anatomy. Various combinations of these characters make it possible to differentiate the six basic groups that Brown designated bambusoid, festucoid, arundoid, panicoid, aristidoid, and chloridoid. Tateoka et al. (1959) surveyed the leaf epidermis of 238 species of grasses and found that two groups, which differ in the type of microhairs present, correspond to the panicoid and chloridoid groups of Prato They also reported that the bicellular microhairs of several genera have distinctive features which suggest that leaf epidermal characters may be useful at the generic level. The most detailed survey of leaf anatomy and epidermis of grasses was made by Metcalfe (1960). He compiled the diagnostic features of the leaf epidermis and internal anatomy of 206 genera, representing 413 species. In addition, he included information on numerous other species, summarized from the literature. The survey by Decker (1964) of 135 genera traditionally placed in the tribe Festuceae demonstrates the value of leaf anatomy in reinterpreting a large, long-recognized tribe. In the present study, the leaf amltomy and epidermis were studied by the author in about 50 species of Muhlenbergia, including those traditionally placed within Epicampes. About 50 additional species of Muhlenbergw, were studied by Reeder at Yale University, and the author was fortunate to have the results of Reeder's unpublished studies for comparison with his own findings. LEAF ANATOMY Comparative studies of lear anatomy were made from transverse sections of leaves of herbarium specimens. Mature blades were selected from about the middle of the culm and sections taken from .. point in the blade approximately 1 em. from the ligule (at this point the vascular bundles and associated structures are well developed; more distally the blades become narrower and certain features become altered). The dry blade was placed in boiling water for several minutes to soften and to bring it back as much as possible to the 86 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM pliable condition of a fresh leaf. In some cases the blades were soaked in a 0.3-0.4 percent solution of trisodium phosphate in a 60° paraffin oven for 1)\-2 hours, although equally good results were obtainable without this additional treatment. Freehand sections were made in all cases. The lea YeS were heavily sclerified and their rigidity permitted thin sec lions (0 be made by hand, thus obviating the use of a microtome. The blade was placed between halves of a block of celloidon and sections cut with It sharp single-edged razor blade. The sections were stained with Chlorazol Black E for )\ hour and then washed and brought through the alcohol series to absolute ethyl alcohol, and made perma­ nent by mounting in diaphane. },1uhlenbergia species traditionally treated as Epicampes possess panicles that are either spikelike or open and pyramidal or columnar. The leaves in the former group become inrolled upon drying (11.1. rigens);in the latter group (he leaves become folded upou drying (M. gigantea). Anatomical studies of the leaves of those two species reveal striking structural differences and the leaves of the other species of the Epicumpes group are of one type or the other. For purposes of discussion, species with the leaf anatomy of }'1. rigens are referred to as having a "Rigens" type, and speeies with a lenf anatomy of M. gigantea are referred to as having a "Gigantea" type. Plates 4-14 contain photomicrographs of leaf cross sections of a number of species of Muhlenberllia, including those of the Epicampes group. A partial leaf cross section of }'1. rigens appears in plate 5, figures 1 and 2, and of 11.1. giganlea in plate 7, figure 2. The anatomical features of Epic am pes leaves are illustrated on plate 4 in cross sections of M. lindheimeri and }'1. palmeri leaves. These two species have a leaf anatomy that corresponds, respectively, to that of 11..1. gigantea nod M. rigens. Anatomical Structure of Leaves of (he Epicnmpes Group' UNITF.: The leaf consists of a series of units of val'ying sizes, each unit representing a single rib of the leaf. The individunl unit contains a vm;cular bundle find u."sociated strnctures between and in­ cluding the upper and lower epidermis.' On plate 4, figure 2 are 'The author i~ gmt,pilll to Dr. C. n. 1\letca}ff' of the Hoyal Botanic Ganic'ns, Kcw, for his aid in interpreting the anatomical fltrlld,I\J'(\"l of the cross section of the leaf of l\f. lindhcimcri from the photomicrograph SPlit to him. & I am employing the term Hunit" as uRed by Brown (lOSS, p. 176) to describe leaves of chloridoid gra.<;scs-"In th<'Sc gronps each bIllHllc', sIlI'nth, and a::,sociat.ed radial chlorcnchyma constitute a discrete unit of strueture f;(~parat('cl from the similar adjacent units by largf', empty, bulliform cclls"-but I cOIlRiclcr also the uppf'r and lower epidermis nnd include fic1erenchyma as part of this unit. The words liprimary," "secondary," and "tertiary" to di~tillguil:1h units are mine. SODERSTROM-PODOSEMUM ANn EPICAMPES 87 shown four units of a blade of Muhlenbergia lindheimeri and below, figure 3, seven units of a blade of M. palmeri. Units are designated primary (I 0), secondary (2°), and tertiary (3°), from largest to smallest. In the Gigantea type, only 1 ° and 2° units are found. The median unit is heavily sclerified at the base. This 1 ° unit and adjacent units are "embedded" in a mass of paren­ chyma, the whole arrangement constituting the "mid vein area," or keel. The keel structure is shown on plate 4, figure 1. The 1 ° units alternate with one to three 2° units throughout the leaf. In the Rigens type, 3° units oCten are present, in addition to 1 ° and 2° units. As seen in M. palmeri one 2° and two 3° units occur between the two 1 ° units. Such an alternation of units occurs throughout the leaf and the central units are not specialized into a keel. VASCULAR BUNnL};s: The phloem of the 1 ° vascular bundles of M. lindheimeri and M. palmeri appears as darkly-stained groups of cells among nonstained thick-walled cells. All of the phloem is darkly stained in the 2° and 3° bundles of these species. The phloem of the 1 ° bundles is sclerosed, i.e., partly converted to lignified fibers. In cross section the active parts of the phloem (sieve tubes and parenchyma) appear as darkly-stained strands embedded in a fibrous ground tissue that is not stained. Sclerosis of the phloem is less pronounced, or lacking, in the 2° and 3° bundles. The xylem of the 1 ° bundles is characterized by large metaxylem vessels on ei ther side of the protoxylem. (The line marking the xylem in the photomicrograph of M. palmeri, plate 4, points to the metaxylem.) These large metaxylem vessels are lacking in the 2° and 3° btmdles; in these bundles both the xylem and phloem stain black and are indistinguishable in the photomicrographs. The 1 ° units are defined as those having metaxylem vessels, which are Iltcking in the 2° and 3° units. In cases where the 1 ° and 2° units are about equal in size, they are distinguished on the basis of whether or not they possess such metaxylem vessels. BUNDLE SHEA"l'HS: Two distinctive layers of cells, or "sheaths," surround the vascular bundle. The innemlOst, variously termed the "mestome sheath," "inner sheath," or Hendodennis" is composed of thick-walled cells. The cells of the inner sheath adjacent to the xylem are larger; the cells adjacent to the phloem fibers are smaller and oft.en indistinguishable from the latter. The inner sheath is surrounded by a single layer of conspicuously larger, thin-walled cells, termed the "parenchyma sheath" or "outer sheath." The outer sheath may be continuous around the inner sheath, or interrupted below, above, or both. In the 1 ° units of M. lindheimeri the outer sheath is interrupted ahove and below, but only above in the 2° units. It is continuous in the 2° and 3° units 221-352--67 2 88 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM of J.f. palmeri. (The closed condition is typical of every unit of the leaf in some species of Muhlenbergia-cf. plate 12, figures 1, 2, and plate 13, figure 1.) CHLORENCHYMA: The chlorenchymll lies adjacent to the outcr sheath and both are stained black in the photomicrograph. Although not evident in the photomicrograph, the cells are radially arranged. The chlorenchyma assumes the same pattern as the outer sheath in the unit, being continuous around the inner sheath or interrupted. (Photosynthetic activity is confined to this narrolV layer of chlor­ enchyma and, presumably, the outer sheath also; together, they constitute a relatively small part of the whole unit [Brown: 1958, p.176]). SCLERENCllYMA: The individual units, especially the 10 ones, possess caps of sclerenchyma cells subjacent to the upper and lower epidennis. The amount of sclerenchyrna varies, but it is especially well developed at the base of the central unit where it reinforces the keel of the blade. In a species with the Rigens type of leaf anatomy the sclerenchyma often forms a continuous layer subjacent to the lower epidermis. TmcK-wALLED PARENCHYMA: Between the vascular bundle and subepidermal sclerenchyrna is a mass of large parenchymatous cells. They are referred to here as "thick-walled" parenchyma,' as the walls of these cells appear to be thicker than in normal parencbymatous cells. These cells constitute a large part of the 10 units, a smaller part of the 20 units, and are lacking in the 30 units. In some cases the thick-walled parencbyma of tbe units is con­ fluent between tbem. Sucb a condition is found in the keel of leaves of tbe Gigantea type in wbich tbe vascular bundles and surrounding sheaths give tbe appearance of being embedded in a mass of paren­ chyma celk In such Cll.'es there is no observable difference hetween parenchyma cells of the units and tbose that occur between them as they are confluen t. COLORLESS CELLS: Between the unit..:;; are found one to several rows of cells that look similar to thick-walled parenchyma. Met­ calfe refers to these as colorless cells. In some gra.,ses bubble-like cells that are part of tbe epidermis are referred to as bulliform cells. Tecbnically, the cells marked (be) in the photograph of M. lind­ heimeri are bulliform cells. The cells subjacent to these bulliform cells are thA colorless cells (cc). In species of the Epicampes group U According to Metcalfe (personal communication), flIt is quite in order to rcfC'f to the cells as thick-walled parenchyma unless they cnn be shown in 1.8. to be appreciably longer than wide. Even if they arc somewhat elongated it is best to refer to them as 'dongatcd parenchymatous cdls' as they urc not fibrous or Bclereids." , SODERSTROM-PODOSEMUM AND EPICAMPES 89 there is no obvious difference between the hulIiform and colorless cells apart from the position they occupy. The Rigens and Gigantea Types of Leaf Anatomy The leaf anatomy of the following species, traditionally placed in Epicampes, was examined: Muhlenbergia distans, M. dislichophylla, M. emersleyi, M. gigantea, M. grandis, M. lindheimeri, M. longiligula, M. macrotis, M. macroura, M. pubeseens, M. rigens, M. robusta, M. speciosa, and M. virlelii. All the above species possess the following anatomical features: (1) The phloem of the 10 vascular bundles is partly sclerosed. (2) The vascular bundle is surrounded by an inner sheath and an outer sheath. Adjacent to the outer sheath is the chlorenchyma, appearing under high power to consist of a layer of narrow cells, radially arranged. (3) A large amount of thick-walled parenchyma occurs adaxial, some­ times abaxial, to the vascular bundle. (4) A thick cap of scleren­ chyma lies below the upper and lower epidermis of the 10 units. Apart from shape, the units of all species of Epicampes are of similar struc­ ture. The major differences are in the kinds of units present and in their arrangement. The Rigens type of leaf anatomy is characterized by the following features: (1) A similar alternation of units occurs throughout the leaf. The 10 units alternate with one or two 2° units or three to five smaller units (consisting of two to four 3° units and a 2° unit). There IS no differentiation of central units into a keel. (2) The lower surface of the blade is flat, or ribbed and furrowed; the upper surface is ribbed and furrowed. (3) The 1 ° units are rounded above in M. macroura (cf. M. dubia, pI. 5, fig. 3), obtriangular in M. rigens (pI. 5, figs. 1,2), and in some species more or less rectangular (e.g., M. elongata, pI. 11, fig. 2). The following species of the Epicampes group possess a Rigens type of leaf anatomy: At. macroura and M. rigens. The Gigantea type of leaf anatomy is characterized by the fol­ lowing features: (1) Only 1 ° and 2° units are present. The central units of the blade are specialized into a keel. The thick-walled parenchyma of these units is confluent and a large cap of sclerenchyma is developed at the base of the central unit. (See M. gigantea, pI. 9, fig. 1, for illustrations of the central and adjacent units of the keeL) Beyond the midrib I1rea is a regular alternation of 10 and 20 unit. •. The 10 units are separatcd by one to three 20 units. (2) The upper and lower surfaces of the blade are ribbed and furrowed. Beyond the midrib area the units are separated by several layers of colorless 90 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM cells. The sclerenchyma subjacent to the lower epidermis is con­ fined to the individual units and therefore does not form a continuous layer between them. (3) The 10 units are more or less rectangular. The central I 0 unit of the keel is rounded or obtuse below. The following species of the Epicampes group possess a Gigantea type of leaf anatomy: M. di8tans, "Ai. distiehophylla, M. emersleyi, M. gigantea (pI. 7, fig. 2, and pI. 9, fig. 1), M. grandi8, M. lindheimeri (pI. 7, fig. 3, and pI. 8, fig. 3), M.lon!Jiligula (pI. 10, fig. I), M. maerotis (pI. 7, fig. I), ~M. pubeseens, M. robusta, M. speciosa, lid. virletii. The Rigens or Gigantea Type in Species of Muhlenbergia Apart from the anatomical differences that separate the speeies of the Epicampes group into the Rigens and Gigantea types, the two groups have the same basic unit structure in the leaves and share the following gross morphological features: Plants perennial, caespitose (usually strongly so); culms erect, not branching at the nodes; and panicle usually densely flowered. The species with a Rigens type of leaf anatomy have rounded basal sheaths, a finn ligule, and the leaves become inrolled upon drying. In contrast, most species with a Gigantea type of leaf anatomy have compressed-keeled basal sheaths, a membranous ligule, and the leaves become folded upon drying. Many species of Muhlenbergia share the morphological features common to all of the species of the Epicampes group. These species may be grouped into those having compressed-keeled basal sheaths and a membranous ligule, and those with rounded basal sheaths in association with a fil1ll ligule. Because of the close morphological similarities to the Epicampes group, a study of the leaf anatomy was made, with the following results: IIfuhlenbergia species with the Rigens type of leaf anatomy: M. anguslata AI. holwayoTum M. arenicola A!. jaliscana AI. articulata AI. Lucida M. capillaris (pI. 10, fig. 2) AI. melcalfei M. duma M. nigra M. dubioides lri. reverchonii (pl. 11, fig. 1) M. elongata (pI. 11, fig. 2) M. rigida ]1,{. expansa (pI. 6, fig. 2) }'-I. seU/olia M. firma M. 8ubaristala M. glabrata AI. xerophila All of the above species have rounded hasal sheaths and a firm ligule. (The rather variable species M. rigida sometimes may have a long membranous ligule.) .SODERSTROM-PODOSEMUM AND EPICAMPES 91 Species that have the Gigantea type of leaf anatomy: M. aUTea M. /ongig/umis (pI. 10, fig. 3) M. breviligula AI. mutica M. gooddingii M. pubig/uma M. inaequali8 M. reederOT"Um M. involuta M. 8coparia M. iridiJolia M. versicolor M. lehmanniana M . xanlhodM These species have compressed-keeled basal sheaths and membranous Iigules with the exception of M. involuta and M. reederorum in which the sbeatbs are rounded (rarely compressed) and ligules finn below and membranous above. Some species of Muhlenbergia exhibit certain anatomical features that require special mention: M. longuiguk (pI. 10, fig. 1). The several 10 units of the midrib area are of equal size. The central unit does not possess a larger basal cap of sclerenchyma than the adjacent units of the keel. The basal sheaths are either rounded or sometimes compressed, but never strongly keeled. However, the structure of the units, the sclerosed phloem of the 10 bundles, and the midrib area of thick-walled paren­ chyma are characteristic of the Gigan tea group of species. M. longiglumis (pI. 10, fig. 3). The central unit is a 10 bundle with sclerosed phloem and a large basal cap of sclerenchyma; both are characters of the Gigantea type of leaf anatomy. The central units, however, are not embedded in a mass of thick-walled paren­ chyma. On tbe basis of leaf anatomy, this species does not confCllm well to either anatomical type but Bhows more similarity to the Gigantea type. M. alf. montana (pI. 11, fig. 3). The units have an arrangement similar to that of the Rigens type. However, the phloem of the 10 units is not sclerosed. M. involuta. All of the units of the leaf are embedded in a con­ tinuous layer of thick-walled parenchyma, unlike the Gigantea species in which such a condition is confined to the keel. Tbe phloem of tbe 10 bundles is sclerosed and the central units possess a large basal cap of sclerencbyma, as in the Gigantea type. The anatomy of the leaf most closely approaches the Gigantea type. M. stricta. The units are all very large and are connected by a continuous layer of thick-walled parenchyma and the phloem of the 10 bundles is sclerosed. The central unit does not possess an addi­ tional amount of basal sclerenchyma. On the basis of leaf anatomy this species exhibits greater similarity to the Gigantea type, but its gross morphology is more like that of species in the Rigens group. 92 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM M. torreyana (p\. 9, fig. 3). The leaves of this species have a keel structurally like that of the Gigantea group, but the phloem of the I" bundles is not sclerosed. Morphologically it is unlike species of the Gigantea group in having short, very scaly rhizomes and branching culms, and a minute, ciliate, firm ligule. Muh1enbergia Species Unlike the Rigens and Gigantea Types Most species of Muhlenberoia have a leaf anatomy quite different from the Gigantea and Rigens types. Although the anatomical struc­ ture of all cannot be discussed here, several points should be men­ tioned to illustrate how these species compare with the Epicampes group and allies. Photomicrographs of 11 species of Muhlenbergia with a leaf anatomy distinct from the Rigens or Gigantea types are shown 011 plate 9, figure 3, plate 11, figure 3, and plates 12-14. All 11 of these species of Muhknbergia differ from species of the Rigens and Gigantea types in the condition of the phloem. The phloem of all the bundles, including the 10 ones, when these are differentiated, is darkly stained throughout, indicating it is com­ pletely functional and not sclerosed. Special reference is made to M. alf. montana (pI. 11, fig. 3) and M. torre1jana (pI. 9, fig. 3). In these species the 10 units are similar to those of the Epicampes group but the phloem of the 10 units is not sclerosed. The annual species are characterized by a relatively simple unit structure, with little additional sclcrenchyma or thick-walled paren­ chyma. Note, for example, the annuals M. confusa (pI. 13, fig. 1), M. cri.8piseta (pI. 14, fig. 1), M. peruuiana (pI. 12, fig. 1), and M. pul­ cherrima (pI. 12, fig. 2). In M. peruuiana and M. pulcherrima tho units are of equal size; the outer sheath and chlorenchyma are con­ tinuous above. Additional sclerenchyma and parenchyma are lacking in the units and the phloem is not sclerosed. M. cri.9piseta has sclerenchyma developed in the central unit and some in each of the other units. The outer sheath and chlorenchyma entirely circle the vascular bundle without interruption and the phloem in the bundles is not sclerosed. Among perennial Muhlenbergi" .. , plates 12-14, are 111. arizanUa (p\. 12, fig. 3), M. asperifalia (pl. 14, fig. 2), M. plumbea (p\. 13, fig. 3), and M. richariUanis (pI. 13, fig. 2). The structure of the individual units in M. richariUanis and M. asperifalia approaches that of the Epicampes group in its specialization. However, the phloem of tbe 1" bundles in these two rhizomatous perennials is not sclerosed. Muhlenbergia plumbea, another rhizomatous perennial, has units mostly equal in size, except for tbe central unit which has a basal SODERSTROM-PODOSEMUM AND EPICAMPES 93 cap of sclerenchyma. Note that the outer sheath and chlorenchyma are continuous around the vascular bundles. The phloem of the bundles is not sclerosed. The leaf of M. arizonica, a perennial that branches at the nodes, is not too unlike that of M. plumbea. The units are mostly equal in size, and the median one is heavily scleri­ fied. The outer sheath and chlorenchyma are continuous around the vascular bundles outside of the central unit. The phloem of the vascular bundles is not sclerosed. Various anatomical configurations in the leaves of the remaining species of Muhlenbergia examined are not illustrated here.' In all of these species the phloem of the vascular bundles is not sclerosed. Conclusions The leaves of species traditionally placed in Epicampe8 are char­ acterized by an inner sheath (or endodermis), a parenchyma (outer) sheath, and chlorenchyma, consisting of cells radially arranged. All are features of the chloridoid type of leaf anatomy, as pointed out by Brown (1958). On the basis of lear anatomy these species are allied to Muhlenbergia, Sporobolus, LyC1l.MJs, and other genera of the chloridoid alliance. In contrast, the leaves of Agrostis and Oinna are of the festucoid type, as Brown has shown, and therefore do not show a relationship to Epicampes. On the basis of leaf anatomy, Epicampes should be removed from the Agrostideae and placed with other members of the chloridoid alliance. The present investi­ gations have shown that Epicampes is most closely related to species of Muhlenbergia which not only have similar gross morphological features, but leaf anatomical features; most noteworthy is the unique condition of sclerosed phloem in the 10 vascular bundles. These findings support those of Schwabe (1949) who in a study of the foliar anatomy of 22 species of Muhlenbergia, including two species of the Epicampes group, concluded that the latter should probably be included in the former. LEAF EPIDERMIS Sections were taken from the upper and lower epidermis of the leaf. In all cases the preparations were made from leaves taken from herbarium specimens. Sections of the blade, 1-1"" long, were placed in boiling water until softened, just as in preparing 1 The reader 18 referred to the treatment. of Schwabe (1949) in which features of the leaves of many additional species of Muhlenberqia are illustrated. 94 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM the whole leaf for cross sections. To remove the epidermis of the abaxial surface the blade was placed with Wle abaxial surfnce down on a clean glass slide. With the aid of the 10 X power of a binocular microscope, the tissue of the leaf was scmped away with It sco.lpel until only the epidermis remained. The same process was repeaterl for the adaxial surf"ce with the adllxial sllrffice dowlI.' The epi­ dermal scrapes were stained with methylene blue and coullterstllinetl with ruthenium red. They were then washed in water to remove the excess dye, brought through tho alcohol and xylene serie', and mounted in Permount. Constituents The epidermis of the grass lear contains a number of different cell types, among them microhnirs, prickle-hairs, papillae, long cells, stomatal cells, interstomatal cells, and silica cells. The bicellular microhairs' and silica cells exhibit the greatest differences between the groups of species within Epicampes. MICROHAIRS: All species studied of Muhlenbergia (including B.picaml'es) have bicellular microhairs. Differences are found in the shape and in the ratio of the length of the basal to tho upper (distill) cell. In some species the microhuirs are short and broad; the basal cell is equa.! to, or a little longer than, the distal cell. In other species the microhairs arc longer Ilnd narrower, and the basal cell is much longer than Ihe distal cell. SILICA CELLS: Silicon-containing cells in the epidermis are referred to as "silicll cells" or "siliceous cells." Characterized by a wall heavier thall that of adjacent cells with small granules within the cell, they occur in rows and fire u. mnjnr constituent of the epidermis in species of the EpiclI.mpes group. In some species all of tJle silica cells are saddle-shaped and rather simple in outline; in ot.hers most of Ihem are dumbbell- or cross-shaped; in st.ill others the lIlajority Ilre saddle­ shaped, with cross-shn.ped cells occurring infrequently among thern. 8 In m!l.ny species, ~.g .• }\t, maCToura, the blade is characterized by n flnt abaxial surface a.nd an adaxial surface of ribs nnd furrows. In such cases the whole epidermis scrapes off easily (rom the abaxia.l surface but only strips of epidermis can be removed from the adaxial surface, representing the top surfaces of the ribs only. , l\lclctl.lfc (1960, p. xliii) remarks, "Mirro-hairs nrc Jlot alwa.ys e:lBy to examine, but it is genernlly rewarding to persevere with them because they arc valuat.le indicators of the affinities of the grosses in which they occur," • • ---- ~ ," -.. ~. . , a b c • • -- - , • - • - • • x e f g o • • - • • • • • CD < d " h • - • • o • AO D -.- .' , FIGUI\E I.-Bicellular microhairs and silica cells. a-d, Species of lection Epicampl.l: d, Diagrammatic cross section of the leaf of M1I.hUnb~rgid lindluinuri,' h, M . ptlhuct'fls (SoJrrstrom 692); c. M. ~i~anUa (Rttder & hew 2488); d. M. mIJ.C1'otis (Mma 9098). rh, Spet:ies of section Podoumtlm: r. Diagram­ matic cross section of the leaf of M. rigt'1l.J; I, M. ";glns (Rttdtr & Rttdtr 2662); t, M. d"hioidu (Sodt rItrom 93 1); la, M. f1tacfoura (Matuda 2829). These are all diagrammatic and are not drawn to scale. ~ ~ i:I: ~ l"l :!! '" '" 01 !J6 CONTRIBUTIONS FROM THE NATIONAL HERRARIUM Following is 1\ summary rrom epidermal studies in Epicampes • speCIes: SAape of ,mea ceU.: S "" ,Ilddle..hapm A ,.'ttI1Ut rll/i l'l lJ/ oo,allo x - (m .... -.hlJJj(d S1)trie, di8tal ctll of microhaiT d ~dulllbbtll.'lIaptd 1\-[, distans 6.6: I s M. distichophylla 5.1 : 1 • M. gigantca 4.0: I s M. grandia 3.2: I , M. lindhcimori - , M. macrotis 5.7 : I s M. macroum 2.2: I mostly x or d ~L pubesccns 4.7: 1 , 1\1. rigena 2.3 : I mixed, 8 and d M. robustA 4.3: I s M. speciosa - , M. virlctii 4.0 : 1 • Species or the Epicarnpes group with a Rigens type or leaf anatomy (M. macroura and M. rigens) exhibit certain characteristics in their epidermis different from the other species of Epicarnpes. The bicellular microhairs are short and broad in these species and silica cells are dumbbell-shaped, cross-shaped, or saddle ... haped. In the specics that have a Gigantea type of leaf anatomy, the bicellular microhairs are generally long and IlILlTOW, and the upper cell is usually much shorter than the basal cell. In these species the silica cells are always saddle-sbaped. The epidermis of other species of Muhlenbergia with a Rigens or Gigantea type of leaf anatomy also was studied. In these, likewise, the epidermis of members with a Gigantea t.ype is characterized by mostly long and narrow bicellular microbairs and rectangular or saddle-shaped silieIL cells. And in the epidermis of species with a Rigens type the silica cells are cross-shape.!, saddle-shaped, or rec­ tangular, and the bicellular microhairs relatively short and broad. In figure 1 are illustrated the major types of silica cells and bicellular microhairs encountered. Conclusions Epidermal leatures of the species of Muhlenbergia, including Epicampes, are panicoi.! in nature; micro hairs are present and the silica cells are rectangular, saddle-shaped, cross-shaped, or dumbbell­ shaped. Relationship with the chloridoid group is apparent in the club-shaped or globose microbairs and membranes of equal thickness on the upper and lower cells (Prat, 1936; Tat,eoka, Inoue, and Kawano, 1!J59; Metcalfe, 1960). SODERSTROM-PODOSEMUM AND EPICAMPES 97 The Emhryo Until recently the structure of the grass embryo has been of passing interest to grass taxonomists, Bruns (1892), who dealt with about 60 species, was the first worker to publish on grass embryos, Later, Van Tieghem (1897) and Kennedy (1899) added to the understanding of the grass embryo, the work of the former being more significant from the standpoint of systematics. Not until Yakolev (1950) and Reeder (1953) was the value of the embryo in grass systematics again stressed. Reeder (1957) in a paper of great significance presented his findings based on a study of the caryopses of ahout 300 species of grasses. These included over 150 genera, representing all of the tribes in the traditional Hackelian system. Reeder showed that several embryo groups could be recognized, and the criteria he used to distinguish them are the relative size of the embryo to endosperm in the ca.ryopsis, as well as the features observable in the transverse and median sagittal sections of the embryo. He listed six groups of grasses based on various combinations of four embryo characters: festucoid, panicoid, chloridoid-eragrostoid, bambusoid, arundinoid­ danthonioid, and oryzoid-olyroid. Reeder later (1962) reinterpreted the oryzoid-olyroid genera a. bambusoid but segregated a further group, the centothecoid. In the present study, mature caryopses were selected from herbarium specimens, placed in boiling water for a few minutes, then soaked over­ night in FAA. They were then transferred to a 3 percent solution of KOH for 1-2 hours to soften the endosperm. After removing the endosperm, the embryo was embedded in agar and the agar block, containing the embryo, run through the butyl alcohol series and embedded in paraffin. Serial sections 10,.. in thickness were made, transversely and longitudinally, in the sagittal plane. Safranin and Fast Green were used in staining. Embryos of 10 species of Mw.lenbergia were sectioned, of which 9 species have been traditionally associated with Epieampes, Of these, 7 have It Gigantea type of leaf anatomy: l.f. emersleyi, M. gigantea, M. grandis, M. longiligula, M. macro/is, M. pubeseens, and M. robusta. All are illnstrated in figure 2 except M. emers/.eyi. Two have a Rigens type: M. macroura (fig. 3) and M, rigens (fig. 2). Additiono.I species, represented in figure 3, are M. nigra, with a Rigens type, and M· 8chreberi, the type species of Muhlenbergia. For comparison, diagrams also of the embryos of five genera that have been suggested as bearing a relationship to Epicampes appear in figure 3: Agrostis, the type genus of the classical tribe Agrostideae, Cinna, Polypogon, SporobolU8, and Stipa. '. 98 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM • • • a b c d e f g h FIGURE 2.-Dutline drawings of caryopscs, median sagittal sections, and transverse sections through the co1coptile region of Muhlmb(1'gia embryos: a, M. macrotiJ (Pringlt 2360); h. M. robusta (Standlty 59136); c, M. rohusta (Pringlt 2321); d, M. grandis (Pringit' 2765); t', M. giganka (Pringlt 3335);/. M. PUbt'SCfflS (Arstnt); g, M.longiligula (ktd" 'C!1 Rud(1' 2699); h, M. rigms (Blum" 1491). Drawings arc diagrammatic and not drawn to scale. a e SODERSTROM-POD08EMUM AND EPICAMPES b f • • if?lZ'i = c iro .~. g - h 99 d FIGURE 3.-<>Utlinc drawings of caryopses. median aagitut .cellons, and transverse scc­ baru through the co1eoptile region of embryos or Multkttb",ia and othtr genera : d, MubkftbtTria macrOfl.rtJ (Al's;u): b, M. nigra (Cook): c, M. uh,tbm (no voucher); d, Art'(!­ stil scabra (Goodding); t, Cinna aruftliintUea (Twudy): I. Polypogon monsptiimsif (Horltu Bol4nicvs BrtlUllnuiJ): " SporoboZus wrightii (GoodJing): h, Stipa dfJtna(ttJ (Rudn f!f hIm 233). Drawings are diagrammatic: and Dot drawn to Icale. 100 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM The caryopses and embryos of Muhknbergia species of the Epi­ campes group bave tbe following features: Caryopsis: Tbe embryo is relatively large in comparison witb tbe endosperm. Embryo: Median sagittal section. 1. A distinct internode is present in the vascular system between the point of divergence of tbe trace to tbe scutellum and tbe trace to the embryonic leaves (P). 2. An epiblast is present (+). 3. A cleft is present between the lower part of the scutellum and the coleorhiza (P). Embryo: Transverse section. 4. The margins of the embryonic leaf contain few bundles and tbe margins do not overlap (F). The embryo formula (see Reeder, 1957) for tbese species is P+PF, tbe cbloridoid-eragrostoid type: Muhknbergia and Sporobolus also are cbloridoid-eragrostoid, but Agros/is, Oin1Ul, Polypogon, and Stipa are festucoid. Muhknbergia macroura and M. nigra differ from the otber species in lacking an epiblast, unusual for chloridoid-eragrostoid species. On the basis of gross morphology and leaf anatomy, however, they are quite similar to M. rigens and an epiblast is present in tbat species as well as in M. dubioUles. Of 12 caryopses examined from a single specimen of Muhknbergia pubescens (Soderstrom 693), 7 had double embryos. However, other specimens of M. pubescens from different localities and all otber species examined had single embryos. Conclusions Tbe embryos of Muhknbergia do not show basic differences cbarac­ teristic of individual groups, except M. macroura and M. nigra which differ in the absence of an epiblast. As emphasized by Reeder, the embryo is most useful in indicating the placement of a grass within one of six natural groups of genera. The species of tbe Epicampes group are like other species of Muhknbergia and Sporobolus and are related to grasses of tbe cbloridoid-eragrostoid group. Tbey do not show a relationsbip to Agros/is and other festucoid genera of the Agrostideae with whicb tbey have been traditionally associated. A summary of embryo cbaracters follows (see also figs. 2 and 3): SO[)ERSTROM-PO[)OSEMUM AN[) EPICAMPES 101 Emb,"oJ IJl,~U'Rode Epiblall Cltft in Embrllcmk IN/ end.tnpam In trace prumt KUltUum 111121"ilU nud. Oenu. and/or .peciu large (P ) pre.ent (+) j1M.ent burnllulew (F) """'''"' .mall (F) (J-') awmt a.~ent ( ) abum margiru OCIerlCl~ (F) (- ) (F) bundlu l1Ulnll ) . M uhknbergia Gigantca type of leaf anatomy M. emeral.tyi P P + P F P+PF M. gigantea P P + P F P+PF M. grandis P P + P F P+PF M. wnUiligula P P + P F P+PF M. macrotia P P + P F P+PF M. pube8cens P P + P F P+PF M. robmt. P P + P F P+PF Rigcns type of leaf anatomy M. macroura P P - P F P-PF M. nigra P P - P (Not seen) P-P M. rigtna P P + P F P+PF Type species M. 8chreberi P P + P F P+PF Agro,ti8 F F + F F F+FF Cinna F F + F F F+FF Polypouon F F + F F F+FF Sparobolu. P P + P F P+PF Slip. F F + F F F+FF Lodicules Lodicules are small hyaline or fleshy scalelike structures subsessile between the lemma and palea of a grass floret. At time of anthesis when they reach their maximum developmen t they become swollen and force the lemma and palea apart, thereby allowing the stamens to become e"serted from the spikelet. They are thought to repre­ sent a reduced inner whorl of perianth parts, the outer whorl having been lost completely through evolution. Although only two lodicules are found in most genera, three are present in the floret of Stipa and most bamboos; lodicules are lacking entirely in Anthozanthum, Cenchrus, and Pennisetum. The lodicules are usually separate, but are fused in Melua and Glyceria. Not only are diHerences in lodi­ cules among genera found with respect to the number present, but also in size and shape, manner of thickening, and vascularization. Zuderell (1909) examined the lodicule anatomy of about 50 species of grasses and in the same year Krause mentioned that lodicules might be of systematic value. ApparentJy, not until recentJy has real emphasis been placed on these structures as indicators of natural 102 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM a <).--_ ............ ~"f1'''''' ,," - " .., " , .~ .- " > ~ " , { , • • , • \ • \. . , / e b " .,' , , , ... " ". ' ~ .- .. ' , , f c ~ ...... { g d FlGURE 4.-Lodicules of Muhlcabergias in the PodoJtm14.m section, aU timet 46: 0, M. angUJtata (Camp E-2519)j b, M. glabrata (Amer. Gr. Nat. Hub. 1356); t, M. dllbia (Soder~ Jtrom 509); d, M. rigida (Soderstrom 640); I, M. macroura (Soderstrom 551); I, M. nigra (Prin gl, 11739); g. M. palm,ri (Pringi, 1417). ,.," / a /1, -." .... -, '- '- t • ~r" .. • • , , ',' .. . ' ;~ ~ c· , , I e • I \. , . f • , !.~ " i;' ... . , • • ~. \ , ., " b ••..... -.~. , "- , ...... , . '. ' , IV f I • I c .... , o· , ~ .~ " \ . JU , " " , • , 'f:-, ;oj--""; . ~- ". '\ g /," \'., ' " , • , k d .';<~ .,. , \ ;~ ~ , .'~ .. ~ . ' ; i r ' . h I, I FIGURE 5.-Lodiculcii of Muhlenbcrgias in the Podol/mum and Epicampn sections, all times 45 : a, M. firma (Amer. Gr. Nat. Herb. 1351); h, M. "",'flr (SodefJtrom 131); c, M .. capilJarir (Krtd & Godfuy 54211): d, M . x"opJr.iJa (GooJJing A-9493); t, M. txpansa (Godfuy 8151): 1, M. aWlicoia (Pring/t 479); g, M. articulata (Pri"g/t 3913); h, M. r(IJtrcMnii (Silfu~u 2478)i i, M. /ongig/umir (Pringlt 2365): i, M. stricta (SOdtrJlrom 642); k, M. ifloo/uta (Silotus 780); I, M. ttntrs/,),j (Sodtrrtrom 746), SODERSTROM-PODOSEMUM AND EPICAMPES 103 , i"· ··'··' •. , a • '-, e , , " .... '. " , ~,,,,, ,.' '. r,_ -_ . ", :/' -'. "' • • I .. , IJ , , " b /C,,' ---"\-.~ c . ..- "\ .' .-'? '; ,. . .. f ~ .. ... < '. " . • • .. ' , , • I '~ • ,:,''' '' '' ''' , . , , , "'" .... ,> " " -,' . , c g , ,I , " :. "'. : i ; "' ... ; , ", .. , , , , ' .~ .... ~. • .... k , , ,; .. • • • , , , ' , " , . !: d .---~.~ ,'.- . , '," ',": · ; , i • .f • • , .. > /' ! \ i \ I-,~ '...V h , .. .. , , ' • > , , , .. • , , , . , .. , , , I FIC1JRE 6.-Lodicules of Muhlenbergiaa in the EpicamptJ section, all time. 46: 0, M. dislans (Pringle 5374); b, M. spuioSQ (Ruder & Ruder 2476); c. M. grand;s (Pringle 2765)j d, M. distichophylla (Pring/I 2346); e, M. rohuJta (Arltnt); I, M. O(flie% r (Smilh 927)i g. M. macrolo (Mexia 9(98); h, M. pUbnU1fl (SodusJrom 483); i, M. lind~im"i (Burr 513); i, M. robwta (SoderJtrom 382); ", M. longiligula (Ruder & Ruder 3222); I, M. g;gantta (Rmltr & Rmk, 2488). relationships. Stehhins (1956), in a study of intergeneric hybrids of Lalium and Fe8tuca, pointed out that cytological findings agree with those based on studies of the grass flower and caryopsis. He illustrated four types of lodicules which he designated panicoid, chloridoid, festucoid, and harobusoid. In t.he panicoid and chlori­ doid types the lodicules are truncate at the apex, but pointed in the festucoid and hambusoid types. Church (1949) also mentioned the value of using cbaracters of tbe grass flower, including lodicules, in systematics. Although Huhhard (1934, 1959 rev.) figured the lodi­ cules of many species, he did not discuss them from a comparative viewpoint. Some understanding of the diversity of structure l1IJlong genera can he gained from his sketches of the lodicules of nearly every species of grass from the British Isles (1954). Bor (1960) likewise included sketches of the lodicules of many grasses. Reeder and Ellington (1960) demonstrated that the genus Ca­ ia:rrwuilja is chloridoid and should he removed from the Agrostideu.e. Their conclusions were based on lodicule anatomy along with emhryo structure, leaf anatomy and epidennis, and chromosome size and number. Tateoka (1960a) also used lodicules, among other floral 221-352--67 3 • 104 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM --- .. -- , " , , a , '-----, , I , \' , .':.- d , , , , , ,\ , , g , b .' ' ", ", (\ , • , " • h e , , • , ~l ,/ :; c '.' , f rl(') \ I ~ / ,I \, , I FI GURE 7.- Lodicules of Muhlcnbergias other than the Padoumu.m or Epicam pn sec tions. all times 50: a, M. quad,idtntata ( flinton 4389); b, M . montana (Arsine 58 Il ); t , M. sc/lrtbtri (no voucher); a, M. wrightii (Go()dding & /Jardin A- 8498) j t, AI. uniflora (Millcr 130); f. M. bi/aba (Pringl! 819); g, M. drpauperafa (Rrtdrr & RadrT 2279); h, M. buviJ (Rudt l & RaJi, 2620); i, M. to,rryi (Goodding M- 189) . .. , ' , , , , , . --: " , " ('0., , \ , , , , , I , iJ , / V "VI a b c d ~ v. ' v, . -. , . ' r--;- , j) • , ' " t:- , , , \~ " J , , I ' j \ , , ", , . " e f g FIGURE 8.-Lodiculcs or r ... luhlcnbcrgias other than the PoJoJtmum or EpicamptJ sections, all times 45: il, M. lyfvaJica (no voucller); h, M. r aUlnfl fa (CQrnman); c, M./rondoIQ (no voucher); d, M. andtna CRud" & Ruder 1808) ; " M. glomrraJQ (RuJ,r & Rada 944); /. M. m,xirQIIQ forma ambigua (no voucher); g, M. torrryana (BiH,ll) • a d • , • • SODERSTROM-PODOSEMUM AND EPICAMPES 105 .. ' . · ..... • • • h ""' +\~'''' ,. , ,0, ! l ~ i '::'~ , , , • , • , , . ,,--", ! r~.'·. " .,' ',' ./ '! • , , . e • -•. t ~; • , • , . '. , b f ...... c / ";-. .;' ';, ~ :', :: ;, " .' ~ ,'. '- ~ \ g "'\.. · . ' " .. .. .. ., ; · .. .. · • • • · , • • • · • · · , · · · / "- • I c "- :"':, · · ' ... , • · · · ,. · .. · · · · · · · . • · . · f FIGURE 9.-Lodicules of genera that have been associated with Epicampts, all times 44: a, SporobollU wrightij (TOMtrU)'); b, Blep4arontlt,on l,i,ltolepi1 (Rutin & Rudn 1807); c, S/1'pa arJ(nacto (Rudn & Rud" 233); d, ilgrosliJ alba (Dltdlty); " Cinna MUfiainoct4 (no voucher); j, Polypogon mOnJptlittuis (Swan); t" LYCUfUJ phhoidtJ (Rudtr <1 Ruder 2352); II, Sporobolus asptr (Nichols); i, Sporobolw Mltraltpis (Nichols). features, to show the relationships of several genera of the Festuceae. Reeder 10 reported on the preliminary results of hiB study of the lodi­ cules of over 300 species, representing 230 genera. Decker (1964), in n study of 135 genera, utilized infollnntion from the lodicules, along with other microcharacters, to determine the naturalness of the classical tribe Festuceae. Hsu's (1963) study is an example of lodicules figured for several species in a single genus. In the present study the 10dicuIes of 47 species of Muhlenbergia (including Epicampes) have been examined. Included are 13 species with a Gigante .. type of leaf anatomy, 15 with a Rigens type, 3 inter­ mediate between the two, the type species of Muhlenbergia, and 15 Ildditionnl species. Line drawings of the lodicules of each of these species, in addition to those of several other genera with which Epicampes has been associated, appear in figures 4-9. The vascular tissue of the lodicules and manner of thickening are indicated in these drawings. All lodicules were selected from spikelets of herbarium specimens in which the anthers were fully developed but not yet exserted. ,t Paper read at meetings of the American Institute of Biological Sciences, Stillwater, Oklahoma, 1960. 106 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM The spikelets were boiled in water for several minutes, transferred to a watch glass, and tho lodicules dissected out under the low power of a binocular microscope. The shape of tbe lodicules was drawn at this t.ime and the areas of thickening noted, then the lodicules were mounted in glycerine jelly without staining. From 2 to 3 weeks later the excess glycerine jelly was removed and the slides ringed with diaphane. The vascularization was drn.wn later from the slides under tbe bigb power of a compound microscope. Most of tbe species of Muhlenbergia examined possess lodicules more or less rectangular in outline. The thickened portion of the lodicules extends from the base to Ilear the apex; the upper margins are of a thinner texture. One to many vascular traces usually are present in tbe form of annular tracheids-rarely are they lacking entirely. According to Stebbins (1956) and Reeder and Ellington (1960), theso lodicules are of the chloridoid type. Tbe lodicules of species with a Gigantea type of leaf anatomy (figs. 51 and 6a-j, /) possess one to four or five vascular traces. Apart from small differences in size and amount of vascularization, the lodicules appear to be rather similar. Lodicules of tbe species with a Rigens type of anatomy (figs. 4a-g and 5a-h) usually possess two to many traces. The lodicules of M. rigens (fig. 5b) are atypical in having no vascular traces; in M. arenieo14 (fig. 5j) the one or two traces present are almost negligible. The considerable difference in lodicule size is attributable to the difference in the size of tbe spikelets. Tbe large lodicules of M. macroura (fig. 4e), M. nigra (fig. 4j), and M. ]lalmeri (fig. 4g) reBect the large spikelet size in these species. Lodicule shape, degree of thickening, and vascularization, with little exception, are similar in all species with a Rigens type of leaf anatomy. Species of Muhlenbergia not of tbe Rigens or Gigantea groups exhibit the same kind of thickening in the lodicules and in degrees of vascularization. The lodicules of many of them are like tbe species with a Rigens or Gigantea type of nnatomy-M. torreyana (fig. 8g), M. guadridentata (fig. 7a), M. montana (fig. 7b), and M. wrightii (fig. 7 mostly 2.5-3 mm. long; blades 3-5.5 mm. wide, flat or inrolled; basal sheaths rounded (southwestern United States and northern Mcxico) . . . . . . . . . . . . . . . . . . . 2. M. lonliligula Spikelets mostly 3-4 mm. long; blades 1-2 mm. wide, involutej basal sheaths compressed and somewhat keeled. Clumes equal to or longer than the floret; lemmas cuspidate or with an awn to 1 mm. long; spikelets averaging 4 mm. long (Mexico: Durango). . . . . . . . . . . . . . . . . 3. M. reederorum Glumes shorter than the floret; lemmas with an awn 1-2 mm. long; spikelets averaging 3.5 mm. long (Texas) .... 4. M. invo]uta Basal sheaths strongly compressed-keeled. Glumes and lemmas glabrous to scabcrulousj culms glabrous to scaberulous below the nodes (Texas and Coahuila, Mexico) . . 6. M. Undheimeri Glumes and lemmas pubescent to lighUy villousj culms pubescent below the nodes (Mexico: Coahuila and Nuevo Le6n) . . . . 6. M. pubialuma 114 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM Ligule not broadly ciecurrent, membranous (rarely somewhat firm below); basal sheaths strongly compressed-keeled; old blades fiat or folded, not arcuate. Sheath auricles present, long and pointed, often more than 1 em. 101\g. Lemmas mostly glabrous. Lemmas awnless or cuspidate, glabrous; spikclets mostly 2.5-3 mm. long; sheath auricles usually 1 em. or more long (Mexico rSinaloa to Oaxaca] and Guatemala). • . . . . . . . . . . 7. M. macrotia Lemmas long-awned, glabrous except for short hairs on the margins toward the base; spikclets most.ly 2-2.5 mm. long; sheath aurIcles usually less than 1 em. long (Mexico [Jalisco south] and Guatemala). 8. M. disticbophylla Lemmas villous (,Michoaclin, Mexico, BOuth to Honduras), 9. M. versicolor Sheath auricles lacking, or, if prescnt, broad and rudimentary, not long and pointed. Branches of the very large panicles widely spreading (tending to open after seed-set), long-naked below; lemmas completely glabrousj ligule usually about 1 em. or more long. Glumes equaling the floret, rounded or aeutish; spikelets generally 1.5-2.2 mm. long (Mexico: Durango to Chiapas). . . . . 10. M. rigantea Glumes several mm. longer than the floret, acute; spikelets general1y 2.5-3 mm. long (Mexico: Veracruz and Chiapas). . . . . 11. M. muUea Branches of the panicle ascending or apprcsscd (usually opening outward at anthcsia, tending to become appresscd at seed-set), long-naked below or floriferou8 to base; lemmas with some pubescence (except usually M. robusta, this species with a short ligule unlike that of M. gigantea and ht. mutica). Glum .. awn-tipped. Lemma short-pilose over the lower half (Colombia and Venezuela). 12. M. inaequaJis Lemma glabrous except for a tuft of short hairs at the base. Spikclets 1-2 mm. long; glumee unequal j blades narrow, 2-3 mm.; ligule 8-16 mm. long, hyaline (Mexico: Chihua.hua to Michoacan). 13. M. seoparia Spikelete about 4 mm. long; glumes about equal; blades wider, 4-7 mm.; ligule 5-7 mm. long, firm (Mexico: Jalisco). 14. M. iridifolia Glumes muticou8, not awn-tipped. Basal sheaths, blades, and culms moderately to densely villous. Ligule about 1 mm. or less long; spikelcts averaging 2 mm. long; a.wns of lemma 1 em. or more long (Mexico: Chihuahua to Jalisco) . IS. M. speeiosa Ligule 1.5-6 (usually 2-4) mm. long; spikcicts mostly 2- 3 mm. long; awn of lemma lacking or, when prescnt, up to 7 mm.long (Mexico: Chihuahua. to Puebla) . . . . . . . . . . 16. M. pubescens Basal sheaths, blades, and culms glabrous to scabrous, but never villous. Lemma all or mostly glabrous (the hairs confined to the base of the margins or rarely prescnt on the midncrvc at the base), awnless or rarely short-awned; plants robust. Sheath auricles present, about 3 mm. long; Jigulc mostly 2-3,5 mm. long; spikelets 2-3 mm. long, ashy gray or purple; lemma glabrous, the margins rarely pubescent at tbe base (Mexico (Naya.rit southJ, Gua.temala, and Nicaragua) .. 11. M. robust. SODERSTROM-PODOSEMUM AND EPICAMPE,S 115 Sheath auricles lacking; ligule 4-12 (usually 4-8) mm. long; spikelets 3-3.6 mm. or more long, dark green; margins of lemma generally short-pilose at the base (Mexico: San Luis Potosito Puebla). . . . . . . . . . . . . . . . . 18. M. virletii Lemma pubescent on the midnerve or lower part to densely villous throughout, if glabrous, then long-awned. Ligule a short rim, generally not over 5 mm. long. Blade much narrower than the sheath at their juncture; old basal sheaths conspicuously brown, curled and fibrillose (Guatemala and Honduras). 19. M. bre,mgul. Blade not much narrower than the sheath at their juncture, old ba~a.l sheaths not conspicuously brown, curled, and fibrillose. Lemmas moderately pubescent or villous on and between the nerves (Mexico: Chihuahua to Puebla) . . . . . . . . . . . . . 16. M. pubeseens Lemmas glabrous above, the pubescence confined to the very base of the margins and midnerve. Culms glabrous below the nodes; ligule 0.3-1.5 mm. long; spikelets 2-2.2 mm. long; glumes slightly awn-tipped (Guatemala: Quezal­ tenango). . . . . . . . . . . . . . • . . . . . 20. M. aurea Colms pubescent below the nodesj ligule 1.5-6 moo. long; spikelets usually 1.5-2 mm. long; glumes acute or slightly erose (MexiCO: Sinaloa to Jalisco) . . . . . . . . . . • . . . . . . . . 21. M. grandi. Ligule often 1 cm. or more long, at least more than 5 mm. long. Lemmas pubescent or villous on and between the nerves; spikelets usually 3 mm. or more long, green or greenish brown. Lemmas densely villous throughout, with awns over 1 cm. long; panicles lead-green or purplish green (Mexico [Michoacan south} and Honduras). 9. M. versieoJor Lemmas sparsely villous, awnless or short-awned (awns much less than 1 cm. long when present); panicles greenish brown or tan (Mexico [Durango south1 and Guatemala). . . . . . . . . . . . . . . 22. M. distaDs Lemmas glabrous or pubescent on the midnerve and/or margins, but not (or hardly) pubescent between the nerves. Spikelets 5-7 mm. long; glumcs sparsely pubescent, awn-tipped (Mexico: Jalisco and Aguascalientes). . . . . . . . . . . 23. M.longigJumis Spikelets 2-3 mm. long (rarely longer) ; glumes glabrous, muticous. Palea pubescent between the keels; callus of Boret truncate (southwestern United States to Oaxaca, Mexico). . .•.... 24. M. emersleyt Palea glabrous between the keels; callus of Boret truncate or acute. Glumes glabrous, shining, almost translucent, nerveless or indistinctly I-nerved; panicle branches short, appressedj callus of Boret truncate (Mexico: Chiapas). . . . . . . . . . . . . 25. M. xanthodas Glumes scabrous, distinctly I-nerved; panicle branches long, ascending or spreadingj callus of Boret acute (Costa Rica to Colombia). 26. M. lehmanniana I. Muhlenbergia gooddingii Soderstrom, sp. nov. Perennis caespitosa, culmis erectis glabris, ca. 60-110 cm. altis, nodis 4, vaginis inierioribus teretibus compressis vel paullo ca.rlnatis glabris; ligula utrinque decurrente, basin versus firma iuscaque, alibi membranacea, margine versus apicem lacerata, ca. 15 mm. longa, laminis arcuatis ad apicem attenuatis, involutis, 50 cm. longis vel 116 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM Iongioribus, ca. 2 mm. Inlis, paniculn dens a nutante slmminea yel purpureo-viridi, axe scaberulo, mllus primariis 3-9.5 (plerumque 3-5) cm. Iongis, secundariis plerumque 1-2 cm. Iongis, tertiams ad 1 cm. Iongis, pedicellis scaberulis, 1-1.5 nun. Iongis, spiculis acutis 2-3 mm. longis, glumis acutis, nonnullis nunute aristalis, plerumque aequalibus, quam flosculo longioribus, glabris vel scaberulis, nervis 0 vel 1 indis­ tinctis, lemmatibus acutis glabris basin versus margine (et plerumque in nervo centrali) puberulis, palea glabm. A M. emersleyi Vasey vaginis magis teretibus, ligula utrinque decurrente, laminis involutis arcuatisque, lemmatibus minus pubes­ centibus, et palea glabra difTert. Caespitose perennial; culms 60-110 cm. tall; nodes 4, glabrous below; basal sheaths rounded to strongly compressed, mrely slightly keeled, glabrous, stramineous, inflated when old; ligule firm, brown, and broadly decurrent at the base, becoming more membranous and lacerate above, the firm lower part 4-7 mm. long, the upper membra­ nous part 1 cm. or longer; sheath auricles lacking; blades of the culm long and narrow, becoming filiform, conduplicate or somewhat in­ volute when dry, 50 cm. or longer, about 2 mm. wide when unfolded, upper surface of blade scaberulous or scabrous, the lower surface scab­ rous, the blades when old firm, brown, and strongly arcuate at the base; upper throat glabrous to scaberulous; collar glabrous. Panicle narrow, nodding, the branches appressed Of ascending, dense, stramineous or light purplish green, 22-45 cm. long, 2-4 cm. wide; axis scaberulous; primary branches mostly 3-5 (rarely as much as 9.5) cm. long, floriferous to near the base, the secondary branches mostly 1-2 cm. long, tertiary branches lacking or, when present, 1 em. or less long; pedicels 1-1.5 mm. long, scaberulous; spikelets 2-3 mm. long (averaging 2 mm. in the holotype); glumes equal or the second a little longer than the first, acute, dentate, many bearing a tiny awn, glabrous or punctate-scaberulous, nerveless or indistinctly I-nerved; lemma a little shorter than the glumes, acute, mostly glabrons except for sparse hairs toward the base of the lateral margins and/or midnerve, 3-nerved, excurrent from below the tip as a flexuous yellow or purple awn 1 em. or longer; palea about equal to the lemma, glabrous or rarely with sparse short hairs between the keels toward the base. Holotype in the herbarium of Yale University; collected in canyon north of Moristo Canyon, Baboquivari Mountains, altitude 4,000 ft., November 19, 1945, by Leslie N. Goodding (No. 462-45). Iso­ types at ARIZ and NY. DISTRIBUTiON: Hestricted in range collected in mountains near the Mexican border in the southernmost Arizona counties of Cochise, Pima, and Santa Cruz, at elevations of 3,000-7,000 ft. Of the two SODERSTROM-PODOSEMUM AND EPICAMPES 117 additional collections from Sonora, Mexico, one is questionably M. gooddingii. UNITED STATES: ARIZONA: COCHISE COUNTY: West slope of Mule Moun~ tains, Goodding M-345 (ARIZ), M-346 (ARIZ); Garden Canyon, Huachuca Game Reserve, Goodding 586-49 (ARIZ); Dragoon Mountains, Goodding 50-56 (ARIZ); Mule Mountains, Goodding 307-61 (ARIZ), 451-61 (ARIZ); Fort Huachuca Military Reservation, Goodding 271-62 (ARIZ). PIMA COUNTY: Quinlin Mountains, GQQdding 179-45 (ARIZ); Baboquivari Peak, Goodding 281-45 (ARIZ, NY, YU); 11oristo Canyon, Baboquivari Mountains, Goodding 408-45 (ARIZ, NY, YU), 457-45 (ARIZ, NY, YU), 460-45 (ARIZ, YU), 468-45 (ARIZ, NY, YU); Canyon N. of Moristo Canyon, Baboquivari Mountains, GQodding 462-45 (YU hoiotype, ARIZ, NY, isotypes) j Coyote Mountains, Goodding & Hevly 53-57; (ARIZ); Quinlin Mountains, Goodding & Lusher 179-45 (NY, YU). SANTA CRUZ COUNTY: Sycamore Canyon, Goodding CG-18 (US, YU), 2996 (UNM), M-394 (ARIZ, YU), 014-40 (YUl. 1IEXICO: SONORA: El Canon de la Bellota, Sierra de la Cabellera, Santos 2110 (SYlU, TEX, US);(1) N. of Babiacora on road to Cumpas, Wiggi .... 7393 (ARIZ, DS, MICII, UC, US). This species superficially resembles some forms of M. emersieyi, as most of the collections have been named. It differs in the rounded or compressed, but rarely keeled, basal sheaths, firm ligules brown below and membranous above, and long-attenuate blades becoming threadlike or filiform. The old blades are usually arcuate at the base. Of the spikelet features to distinguish the species, the lemma and palea are significant; in M. gooddingii the hairs on the midnerve and margins are sparse and confined to the lower part and the palea is glabrous between the keels. The panicles of M. gooddingii are narrow and densely flowered and the lemmas are always awned. Such plumelike panicles among the filiform foliage probably create a distinctive look to this species in the field. Muhlenbergia gooddingii cannot be called a typical member of section Epwampes because its features of the firm ligule, brown below, and the more or less rounded basal sheaths are characteristic of the Podosemum section. Because of its combination of characters a possible ancestry is suspected in M. wersieyi and M. longiligula, for the new species occurs in the overlap of range of the other two species and M. good­ dingii has features of both. A comparison of many characters from descriptions in this paper illustrates the intermediate position of M. gooddingii, as shown below: culms nodes M. emt16lelfi 1-1.5 (occasionally to 2) meters 3-4, glabrous or somewhat puberu­ lent below M. lcmgillgula 60-130 (100) em. 1 or 2 on lower part, glabrous M. gooddingil 60-110 em. 4, glabrous below 118 CONTRIBUTIONS ~'ROM THE NATIONAL HERBARIUM .\t. tmer~leuj M.lonailloula M. Qooddinoii basal compressed, keeled, rounded, rarely rounded to strongly sheaths glabrous compressed, but compressed, rarely never keeled; slightly keeled; scaberulousj glabrous; old old sheaths sheaths expanded expanded ligule membranous, u8unl- firm, brown, de-- firm, brown, broadly Iy a little firmer current, somo- decurrent at base, at base than ti mes becoming becoming mem- above where thin membranous at branous and and usually tip lacerate above lacerated into narrow strands blades 2-6 mm. wide, Hat long-attenuate to long, narrow, ~ or folded, 23-41 a brown, coming filiform j (mostly 20-40) pointed tip, conduplicate or em. long flat or in rolled somewhat involute at edges; to 65 when dry; 50 em. (20-40) em. long, about 2 mm. long, 3-5.5 wide (usually about 4 mm.) wide blade aurCace upper : glabrous to upper: glabrous upper: scabcrulous aco.bcrulous to seabcrulous or scabrous (mostly scubcr- ulous) lower: scabrous lowcr: mostly lower: scabrous scabrous old bl.des brown, not especially brown, firm, firm, brown, firm, not arcuate folded and strongly arcuate somewhat at base arcuate panicle typically lax above, eroot, narrow nodding. the branches branches loosely greenish to apprcssed or as- ascenrling or purple ecn(ling, dense, sprelldingj light stramillcous or purple to pur- light purplish plish tan green panicle 20-40 (mostly 30- 15-55 (30-45) em. 22-45 em. long, dimensions 40) ern. long, 4-1 long, 1- 5 (gcn- 2-4 em. wide em. wide (marc erally 1.5- 2) in field) cm. wide 10 branches 9-17 (9-12) em. to 13 (generally 3-5 (to 9.5) em. long 3-5) em. long long 2° branches 3-9 (3-5) em. long to 5 (genernlly 1-2 em. long 1- 2) em. long 3° branches 0.5-4.5 (0.5-1.5) lacking lacking or to 1 em. em. long Long spikelets 2.2-3.2 (2.5-2.7) 2-3.5 (usually 2-3 (2) mm. long mm. long 2.5-3) mm. long glumcs lemma. SODERSTROM-PODOSEMUM AND EPICAMPES 119 M. emenZell' broadly acute &cutish j pubescent on midnerve and margins ~-~ their length M.10'n{l1l1qrMa acutish, some­ times midocrvc extending into 8. minute awn glabrous (rarely ecabcrulous) M. gooddlnqU acute, dentate, many bearing a tiny awn moaUy glabrous except for sparse hairs toward base of margins fl.od/or midnerve awn of lemma 0 to 1.5 em. long rarely 8. minute awn present glabrous 1 em. or more long paisa pubescent between the keels »-~ their length glabrous or rarely with sparse short hairs between the keela toward the base This species, with a rew exceptions, has been collected by Mr. Leslie N. Goodding, a long-time resident or Arizona, staunch conservationist, and botanist keenly interested in tbe Arizona flora. It is a pleasure to recognize Mr. Goodding's interest in grasses and contributions to Arizona botany by naming for him this predominantly Arizona species. 2. Muhlenbergi. longillguJ. HilAlhc. Amer. Journ. Bot. 21 :136. 1934. Epicampesligulata Scribn. in Vasey, Contr. U.S. Nat. Herb. 3(1) :58. 1892. Basis of Muhlenbergia longiligula Hitchc., not M. ligulata Saribn. and Merr. (Pringle, Santa Rita Mts., Arizona, July 26, 1884, selected by A. S. Hitohcock as lectotype). Epicampes anomala Scribn. in Beal, Grasses N. Amer. 2:311. 1896. (Pringle 1423, Arroyo Ancho, Sierra Madre, Chihuahua, Mexico). Not Muhlenbergia anomalit Fourn. 1896. Epicampe8 distichoph1lUa V8r'. mutica Scribn. in Beal, Gra85Cs N. Amer. 2:308. 1896 (Tourney 740. July 23, 1892, Arizona). Epicampes strida var. mutica Jones. Contr. West. Bot. 14:6. 1912. Based on E. distichophylla var. mutica Scribn. Strongly caespitose perennial; cuhns glabrous, becoming scaberulous toward the panicle, 6()-130 cm. (usually about 1 meter) tall; nodes 1 or 2, on the lower part, glabrous; basal sheaths rounded, rarely compressed, but never keeled, glabrous to scaberulous, loosely im­ bricate, the old sheaths expanded, yellowish brown, persistent; ligule finn, brown, decurrent, sometimes becoming membranous at the tip, especially in the uppermost blades of the culm, 1-3 (usually 1-1.5) cm. long, distinctly 2-keeled when large and broad; sheath auricles lacking; blades of the culm to 65 (usually 2()-40) cm. long, long-attenuate to a brown, pointed tip, flat or inrolled at the edges, 3-5.5 (usually about 4) mm. wide when flat, the uppermost blade of the cuhn beneath the panicle short, the upper surface of the blade glabrous to scabrous 221-352-67 'f • 120 CONTRIBUTIONS FHOM TIlE NATIONAL HEHBAHIUM (mostly scaberulous), the lower surface mostly scabrous, the old hlades brown, firm, folded, and somewhat arcuate at the point of attachment to the sheath; upper throat glabrous; collar glabrous (rarely scabcru­ lous). Panicle erect, narrow, the paniclo branches borne in bunches along the axis, branches of the lowest rluster shorter than the clusters above, an interruption usually present between tbe hnsol and re­ maining clusters, greenish to purple, 15-55 (usually 30-45) em. long, 1-5 (usually 1.5-2) cm. wide; axis glnhrollS to scabrous (mostly scabrous), the primary hranche., to 13 (usually 3-5) cm. long, the secondary hranches to 5 (usUlllly 1-2) em. long, bearing spikelel' almost to the point of attachment of the secondary with the primary branches, tertiary brunches lacking; pedicel, very short, glabrous to scaberulous (rarely scabrous); spikelet.<; 2-~.5 (mostly 2.5- 3) mm. long; glumes usually longer than the floret, hut often shorter, especially in the longer spikelets, usually equal or the second a little longer than tho first, glabrous to scaberulaus, acutish at the tip, sometimes extending into a minute awn, nerveless or I-nerved; lemmas 2.5-2.9 mm. long, glabrous (rarely scaberulous), indis tinctly 3-nerved, rarely with a minute awn; palea equal to or often a bit longer than the lemma, glabrous. Lectotype in the U.S. National Herbarium, no. 746686, collected in the Santa Rita Mountains, Arizona, elev. 4,000 ft., July 26, 1884, by C. G. Pringle (without number). Hitchcock has written on the type sheet, "Selected as probable type. The Texas specimens are different and do not agree with the description. Noto long firm ligule." Isolectotypes at F, GH. DISTRIBUTION: Rocky mountain slopes and canyons, at elevat.ions of 5,000-9,000 feet, most frequently found in exposed areas oC the pine-oak ZOlle at 6,000-8,000 feet, oeensinnally in ligbtly Crosted areas where more shaded. Rather common from New Mexico to Arizona into northern ?vfexico, occurring in Sonora, Chihuahua, and Durango. Also reported from western Texas and southern Nevada. UNITED STATES: NEW 1\lExICO: Mountains W. of Gray, Gooddino M-252 (ARIZ, US), M-254 (ARIZ). C:\THON COUNTY: Apache National Forest, Laney 16 (UNM); Solheim'" Solheim 2343 (OH). ~lang •• , Metcalfe, Sept. H, ]897 (GH, NY, US). GRANT COUNTY; Black Range, Gooddin(J &! Goodding 367 (ARIZ). Santa JUta del Calve, WTight 1973 (CAS, o II, MO, NY, UC, US). GREENLEE COUNTY: Castle Creek, Apnche, Utzat 14 (UNi\-1). SOCORRO COUNTY: Mogollon Mountains, Metcalfe 556 (ARIZ, GH, l\lO, NY, PO:\I, US). ARIZONA: Emersley 47 (US). Upper Oak Creok, Fulton 7345 (ARIZ). Pefia BLanca Mountain8, Goodd1'ng, Sept. 20,1935 (ARIZ)j Jones, Sept. 20,1884 (US). Rocky Canyon, Rothrock, in 1874 (F, CII, NY). Oak Creek Canyon, WeaOu:rwax 2782 (TAES). APACHE COUNT\,: Diamond Creek, Gould & Robinson 5030 ARIZ, NY, TAES). Reservation Ranch, lYauer, Aug. 1936 (ARIZ). COCHISE COUNTY: Chiricnhutt. Mountain8, Hlumer 189 (ARIZ). Barfoot Park, Blumer SODERSTROM-PODOSEMUM AND EPICAMPES 121 1424 (ARIZ, DS, F, GH, MO, NY, US). Herb Martyr Dam Area, uChiricahua Vegetation Team" 59-803 (ARIZ). Carr Canyon, Darrow, Gould, Phillips, & Pultz 1437 (MO). Rock Canyon, Huachuca Game Reserve, Goodding 884-49 (ARIZ). Fort Huachuca Military Reservation, Goodding 568-58 (ARIZ, YU), 720-58 (YU). Pinery Pass, Goodding &: Goodding 463 (ARIZ, UC). Carr Canyon, Gould, Darrow, Pultz & Phillips 2461 (CAS, UC, US). Divide between Carr and Ramsey Canyons, Gould & Haskell 3363 (ARIZ, NY, UC, US). Rucker Canyon, Gould &: Haskell 4585 (ARIZ, GH). Bowie, Jones 4290 (ARIZ, POM, SMU, US). Huachuca Mountains, Jones, Sept. 3, 1903 (POM); Lemmon & Lemmon 2921 (GH), Sept. 1882 (US). Pine Canyon, Tourney, Sept. 10, 1896 (US). COCONINO COUNTY: Long Valley Ranger Station, Coconino National Forest, Darrow 3262 (ARIZ, CAS, US). Pine Flat Camp, Oak Creek Canyon, Darrow, Sept. 16, 1943 (ARIZ). GILA COUNTY: Mt. Ord, Goodding 123-47 (ARIZ). Young, Goodding &: Goodding 341 (ARIZ). Long Valley, Pine­ Winslow Road, Goodding &: Goodding 354 (ARIZ). 5 mi. N. of McFadden Peak on Young Road, Gould 3915 (ARIZ, US). Workman Creek Canyon, Gould &: Hudaon 3793 (ARIZ, MO, UC, US). Cassadore Range, Gould &: Robin8on 4896 (ARIZ, UC). White Mountains, Griffith. 5367 (US), 5409 (GH, US), 5434 (US). GRAHAM COUNTY; 3 mi SW. of Point of Pines, 70 miles E. of San Carlos, Bohrer 421 (ARIZ, CAS). Bluejay Ridge, Gandy 8 (UNM). Mt. Graham, Hope 9999 (ARIZ, MICH, US). GREENLEE COUNTY: Red Bluffs road above Blue, Goodding & Goodding 349 (ARIZ, US). Big Lue Range, Gould &­ HaskeU 4064 (ARIZ, UC). 15 mi. N. of Blue, Gould &: Robin.on 5143 (ARIZ, TAES, UC). MARICOPA COUNTY: Sugar Loaf Mt. Wonderland of Rocks, Darrow, July 8, 1937 (ARIZ). NAVAJO COUNTY: Fort Apache, Mayerhoff 89 (F) j Schroeder, in 1937 (ARIZ). PIMA COUNTY: Mt. Lemmon Road, Benson 9106 (ARIZ, DB, POM). Manning Camp, Blumer 3412 (ARIZ, DS, GIl, MO, UC). Santa Catalina Mountains, Brown 135 (ARIZ), Darrow, Oct. 3, 1937 (GH). Prison Road, Ginter, Oct. 6, 1941 (UC). Moristo Canyon, Goodding 451-45 (ARIZ, NY). Santa Rita Mountains, Griffiths & Thornber 122 (US). Mt. Lemmon, Bear Canyon, Hevly 1028 (ARIZ). Santa Rita Mountains, Kearney & Peebles 10543 (ARIZ, MICH, US). Bigelow Tower, Leader &: Leader 276 (ARIZ). San Luis Mountains, Mearns 373 (US). Rincon Mountains, Nealley 65 (NY, US), Aug. 1881 (GH, MO). Upper Bear Canyon, Santa Catalina Mountains, Parker 7099 (ARIZ). Mt. Lemmon, Peebles & Harrison 2294 (US); Peebles, Harrison & Kearney 2il39 (ARIZ, US). Santa Rita Mountains, Pringle, July 26, 1884 (US lectotype, F, GH, isolectotypes). l\1adera Canyon, Silveus 3468 (TAES, TEX, US). 1\.1arshall Gulch, Thornber 2767 (ARIZ). Box Springs, Tkomber, Aug. 10, 1906 (ARIZ). Tucson, Tourney 740 (DS, NY, US, isotypes of E. distichophylla var. mutica). SANTA CRUZ COUNTY: White House (Madera) Canyon, Ben,on 9780 (POM); Gould 2597 (ARIZ, UC, US); Leader &: L,ader 198 (ARIZ). Sycamore Canyon, Goodding M-111 (ARIZ), M-259 (ARIZ, US). Santa Rita l\lountaina, Griffith8 6074 (MO, US). Santa. Catalina Mountains, Thornber 7689 (ARIZ). YAVAPAI COUNTY: Jerome, Benham M-34 ARIZ), M-I05 (ARIZ); Goodding 75-46 (ARIZ). Mingus Mountain, Benham 43-B (ARIZ, MICH). Prescott, Purch .. , 513 (ARIZ). MEXICO: SONORA: San Jose Mountains, Marshall 173 (ARIZ); Mearns 996 (US), 1649 (US). El Tigre, Rio de Bavispc, Santo. 1963 (ARIZ, GH, MO, NY, SMU, TEX, US). E1 Picacho del Pilar, Rio de Bavispe, Santos 2164 (GH, SMU) CHIHUAHUA: Bctwcen Rio Chico and Rfo Caballo, Barlow, Sept. 30, 1911 (F, UC, US). Slinchez, Hitchcock 7667 (NY, US). Marsh Lake, Jones, Sept. 19, 1903 (POM). N. de Cd. Madera, Martinez F-2477 (CHAP, US). 35 km. SW. of Minaca, Pennell 18928 (MEXU). NK of Colonia Pacheco, 122 CONTRiBUTIONS FROM THE NATIONAL HERBARIUM Pennell 19194 (VS). Arroyo Aneho, Pringle 1423 (GIl, US, isotypes of E. anomala) Sierra Madre, Pringle 1427 (F, GH, "Y, US), 1703 (VC). 27 mi. NW. of Cd. Madera, Reeder & Reeder 2663 (YV). Cn. 43 mi. SW. of Casas Grandcs, Reeder & Reeder 2692 (YV). 38 roi. S. of C .... Grandcs, Reeder & Reeder 2699 (YD). 31 mi. W. of Colonia Juarez, Reeder &: Reeder 3222 (YV). Palimos Calion CIl. 13 mi. E. of Chuhuichupa, Reeder, Reeder, & Goodding )222 (YU). s. or lIcrn~Ddez, Reeder, Reeder, & Soilerstrom 3505 (US, YlJ), 3509 (US, YU), 3531 (VS, YD). DURANGO: 6.5 mi. W. of E1 SalLo, Reeder & Reeder 2639 (YV). 25 roi. W. of Dumngo, Reeder, Reeder, & Soderstrom 3439 (US, YU). Muhlenbergia longiligula is distinguished by its long, firm, decurrent ligule and rounded basal sheaths. On the basis of leaf anatomy, the long glumes, the dorsal awn (when present), and the general hahit in the field, it seems to belong with the Epicampes section of Muhlen­ bergia. The firm ligule and rounded basal sheaths are also charac­ teristics of species in the Podosemum section. Thus, M. longiligula possesses characters of both sections, "nd it appears to be more of a link between them than a distinct member of either. The closely allied species of tbe subgenus Podosemum, M. lindheimeri, M. involuta, l.f. pubigluma, and M. reC(wrorum, all possess the decurrent ligule. Of these M. invol1tta and M. reederorum, like lvI. longiligula, lack strongly compressed-keeled sheaths. All occur within the same general range, l.f. longiligula ranging from southwestern United Stales into northern Mexico, M. lindheimeri in south-centrru Texas and Coahuila, M. involuta in 'fexas, M. pubigluma in CoahuillL and Nuevo Le6n, and M. reederorum in Durango, Mexico. 3. Muhlenbergia reederorum Soderstrom, sp. DOV. Perennis eaespitosa, culmis angus tis scahris, CI1. 1 m. aitis, basin versus nodis 3, pnberuientis, vaginis inlerioriblls compressis et paullo cl1rinatis glabris; collis scaberulis; ligula utrinque decurrente, hasin versus fIrma et fusca, alibi membrana,cea et margine versus upicem lacerata, ca. 10-15 mm. longa; laminis culmi usque ad 65 cm. longis laete viridihus involutis, attenuutis et ad apicem filiformibus, laminis vetustis Iusch~ firmis arcuatis, ca. 1.5 mm. Intis, utrinquc scabris; panicula erecta, cetera laxa, laete viridi 30-47 cm. longa, quando appresslL 2-3 ern. lat", axe scabro, ramis primariis 4- 6 cm. longis, secundariis Cit. 2 cm. longis, tertiariis ca. 5 mm. longis, pedicellis scaberulis, lateralibus 1.5-2.5 mill. longi., terminalibus 2-3 mill. usque ad. 6 mm. longis; spiculis lanceolatis 3.5- 4.6 (plerumque 4) mm. longis, glumis acutis fere aeqllalibus, quam flosculo longioribus, scaberulis, nervis 0 vel 1, indistinctis,lemnll1tihus scaberulis, infra apicem minute aristatis, quam glumis paullo brevioribus. A M. involuta Swallen vaginis magis carinatis, glumis quam lem­ matibus paullo longioribus, spiclllis longioribus, paniculis longioribus, et aristis quam lemmatibus brevioribus differt. SODERSTROM-PODOBEMUM AND EPICAMPES 123 Caespitose perennial; culms rather slender, scabrous, erect, about 1 m. tall; nodes 3, puberulent below; basal sheaths compressed and somewhat keeled or comprcssed only, glabrous, purplish toward the base when young; collar scaberulous; ligule decurrent, the lower Y:r%: firm and brown, the upper half membranous and lacerate, about 10-15 mm. long; shellth Iluricles lacking; blades of the culm up to 65 cm. long, light green, tightly folded, long-attenuate becoming filiform, the old blades brown, firm and arcuate, about 1.5 mm. wide when flat, the upper and lower surfaces scabrous; upper throat scabrous. Panicle erect, grayish green, 30-47 Col. long, 2-3 cm. wide when appressed, more open at anthesis; axis scabrous; branches of the panicle narrow, the primary branches 4-6 Col. long, secondary branches 1-2 cm.long, tertiary branches lacking or about 5 mm. long; pedicels evenly scaberulous, those of the lateral spikelets 1.5-2.5 mOl. long, of the terminal spikelets 2-3 (to 6) mm. long; spikelets lanceolate, 3.5 4.6 (averaging 4) mm. long; glumes acute, about equal, scaberu­ lous, nerveless or indistinctly I-nerved; lemmas a little shorter than the glumes, scaberulous, 3-nerved, bearing a rudimentary awn 0.2-2.5 mm. long from just below the tip; palea glabrous. Holotype in the Yale University Herbarium, collected in the Sierra Madre Occidental (yV. of Ciudud Durango), 7 miles E. of Navios, Durango, Mexico, elevation 7,700 ft., Sept. 26, 1963, by J. R. &: O. G. Reeder (no. 3834). Isotypes at F, K, MEXU, MICH, NY, P, UC, and US. DISTRIBUTION: Known from Durango and possibly Jalisco, Mexico. The type specimen was collected in the Sierra Madre Occidental west of the city of Durango, wbere the large caespitose clumps are found on rocky canyon walls in the pine-oak zone at elevations of 7,700- 8,800 ft. MEXICO: DURANGO: 4 mi. W. of Nav[08, Reeder & Reeder 4230 (US, YU); 7 mi. E. of Navfo.!, Reeder, Reeder, & Soderstrom 3436 (US, YU). 2 mi. SW. of Buenos Aires, Reeder, Reeder, & Soderstrom 3347 (YU) . (1) JALISCO: Mountains N. of AutUn, 3-5 mi. above Mina San Francisco, McVaugh 19669 (MICH, US). Muhlenbergia reederorum exhibits greatest similarity to M. involuia, known only in Texas. In M. involuia the basal sheaths are oompreBSed, but not keeled; in M. reederorum they are usually more keeled, but the keel is not strong. In M. reederorum the gJnmes are a little longer than the floret, but much shorter in M. involuia, the spikelets are longer, averaging 4 mm., the panicle is longer, up to 47 cm., and the glnmes are acute and entire at the apex. Muh1enbergia longiligula is also similar in many respects but its un awned lemmas and flat, wider (3-5.5 mm.) blades separate it from the new species. The many long, narrow blades of M. reederorum produce softer and more delicate 124 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM clumps in the field than the typical coarser clumps of other species of the Epicampes section. A unicate specimen (Reeder, Reeder, &: Soderstrom 3347) collected near Buenos Aires, Durango, differs from the material of the type locality in the more membranous ligule, the longer awn of the lemma (up to 2 mm.), and the wider blades (up to 2.5 mm. wide). This previously undescribed species is named in honor of Professor John R. Reeder of Yale University and his wife, Charlotte Goodding Reeder. Because of their interest in the Gmmmeae, especially of Mexico, and the genus M:uhlenbergia it is appropriate that a Muhlen­ bergia from tbat country bear their name. 4. MuhJenbergia involuta SwaUcn. Amer. Journ. Bot. 19 : 436./. 2. 1932. Caespitose perennial; culms glabrous or scaberulous at the base, to 135 (usually 70-100) cm. tall; nodes 4 or more, mostly glabrous or puberulent beneath; hasal sheaths compressed, but not strongly keeled, tightly imbricate, yellowish brown, not becoming fibrillose wben old; ligule dccurrent, finn and brown at the base, becoming acute and membranous only toward the tip, often firm about three­ quarters of its lengt.h, memhranous one-quarter of tbe length , to 1.2 cm. long; sbeath auricles lacking; blades of tbe culm to 45 cm. long, pale green, often arcuate, long-attenuate to a firm point, tightly folded, 1-2 mm. wide when unfolded, tbe upper surface of the blade scabrous, bearing a mat of numerous tightly appressed white hairs (spicules), the lower surface of the blade scabrous; upper tbroat scabrous; collar scnberulous. Panicle erect, greenish to tan, to 40 (usually 20-30) cm. long, 1.5-7 cm. wide, branches of the pnnicle long; axis scabrous, tbe primary branches 6-9 (usulllly 6-8) em. long, the secondary branches 1-4 (usually 2-3.5) em. long, the tertiary branches to about 2 (usually 1 or less) cm. long; pedicels of the tenninru spikelets very long, equal­ ing the spikelet or, more often, much longer, pedicels of tbe lateral spikelets usually sborter than tbe spikelet; spikelets 3-4 (averaging 3.5) mm. long; glume" equal or the second 1 mm. or more longer tban the first, sligbtly tootbed at apex, occasionally benring a rudimentary awn, usually glabrous but sometimes scaberulous, I-nerved; lemmu", 3.2-4.2 (usually 3.5) mm. long, usually mu('.h longer than the glumes, rarely ahout equal, glahrous or with a few hairs at the base of the lateral margins, ratber strongly 3-nervcd, awned, the awns }-2.4 (usually 1-2) mm.long; palea about equal to lemma, gl.tbrous. Type in tbe U.S. National Herbarium, no. 1501594, collect.ed on draws in bills, 20 miles NE. of San Antonio, Texa"" Oct. 10- 31 (year not cited), by W. A. Silveus (no. 358). SODERSTROM-PODOSEMUM AND EPICAMPES 125 DISTRIBUTION: Rocky banks and draws of hills, usually on lime­ stone soil. Of very limited distribution, in south-central Texas. UNITED STATES; TEXAS; BANDERA COUNTY; Bandera, Silveu. 7393 (TEX). BEXAR COUNTY; Hills NE. of San Antonio, Silv.,.. 314 (TEX, US). 20 mi. NE. or San Antonio, Silvtua 358, = Amer. Gr. Nat. Herb. 1324 (US Hoiotype, CAS, GIl, LL, MO, SMU, UC, isotypes). BOERNE COUNTY: Open calcareous hillsides, Palmer 10829, in 1916 (US). BUUNET COUNTY: S. of Burnet, Silveu& 7676 (ARIZ, CAS, DS, SMU, TAES, TEX). HAYS COUNTY: W. of Cedar Valley, Edwards Plateau, Gould 5336 (TAES). KENDALL COUNTY; Spanish Pass, Cory 26212 (TAES, US). SW. of Boerne on the Boerne·Bandera road, Silveu8 780 (TEX, US). Comfort, Silv,us 2335 (CAS, TAES, TEX), 7339 (CAS, TAES, TEX). KERR COUNTY: NW. of Kerrville, Reed, Sept. 28, 1931 (US). TRAVIS COUNTY: \V. of Trading Post on cut off road to Pcdernales Bridge, Brown 50-323 (SMU, TAES, TEX). Glen Rose, W. of Austin, Moon 167 (TEX). Austin, ThaTp 3968 (TEX), 5198 (TEX). Pedernales road, 8 mi. W. of Bre Cave, ThaTp 53-250 (TEX). W. of Austin, Warnock 45-27 (TEX, US). Hamilton Pool, Websler 1961 (TEX). Muh1enbergia involuta is distinguished by its firm, decurrent ligule, in combination with the compressed but not keeled basal she"ths, the tightly folded arcuate blades, and glabrous lemmas that usually exceed the glumes in length. Swallen, in describing this species, remarked, "MulUenbergia inooluta is rel .. ted to M. distichophylla (Presl) Kunth but in that species the spikelets are only 1.5-2 mm.long, the awns are 10-15 mm. long, the blades are flat, as much as 5 mm. wide, and the sheaths bear auricles 2-3 em. long. In both species the glumes are shorter than the floret." However, M. involuta, is by no means closely related to M. distichophylla. The latter is allied to M. macrotis and M. robusta in which the sheaths bear rudimentary to very long auricles, the lemmas are glabrous, and the ligule membranaceous throughout. In M. involuta the ligule is decurrent, very firm and brown at the base, becoming membranaceous only at the tip. This char ... ter, in addition to the pale green, firm, tightly folded arcuate blades, indicates that it is closer to 111. lindheimeri, M. pubigluma, and M. reederorum. Muh­ lenbergia inooluta is endemic to Texas, M. lindheimeri to Texas and Coahuila, M. pubuJZIlma is kn own only from Coahuila and Nuevo Le6n in northern Mexico, and M. reederorum only from Durango (and possibly Jalisco), lI.fexico. The distribution of these species in Texas, Coahuila, and Durango separates them from M. distichophylla from farther south, Julisco, Mexico, into Guatemala. 5. Muhlenbergia IIndheimeri I1itcbc. JOUlo.. Wa8hington Acad. Sci. 24(7) :29l. 1934. Epicampes gracilis Trin. Mem. Acad. St. Petersb. VI. Sci. Nat. 4:271. 1841. Fragments of panicle of this specimen ex Trinius herbarium (LE), in type collection at the U.S. National Herbarium marked "EpiC4mpelJ gracilil in 'Mexico de Karwinsky.' JIb. Reg. MOURe (Munich) no. 595." The published locnlity of this specimen is Mexico, but the species is known only 126 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM from south-central Texas. This reference is doubtless made to territory now Texas but which was still part of Mexico ill 1841. Not Muhlenbergia gracilis (H. B. K.) Kunth. 1829. Strongly caespitose perennial; culms stout, robust, glabrous, 0.5-1.5 (mosLly more than 1) meters tall; nodes 4, glabrous beneath the nodes; basal sheaths compressed-keeled, glabrous, tighLly imbricate and usually yellowish or purplish brown; ligule decurrent, firm and brown at the base, becoming membranous above, usually enclosed within the tighLly folded blade, up to 3.5 (mostly 1-1.5) cm. long; sheath auricles lacking; blades of the culm 25-55 (usually 30-45) cm. long, narrow, pale green, very firm and conduplicate, 2-4 (usually 2-3) mm. wide when flat, the upper surface of the blade scabrous, bearing a tight mat of dense short white hairs, the lower surface scaberulous to scabrous; upper throat scabrous, bearing a dense mat of short white hairs; collar glabrous to scaberulolls. Panicle erect, narrow, pale green or tan, the panicle branches floriferous almost to the base, occurring in bunches at in tervals along the axis, the nuked portion of the axis sometimes obvious, sometimes obscured by the overlapping appressed panicle branches, to 50 (mostly 2(}-30) cm. long, 1-3 (mostly 1.5-2) cm. wide; axis scabrous, the primary branches to 5 (mostly 2-4) cm. long, the secondary branches to 1.5 (mostly 0.5-1.5) cm. long, tertiary branches lacking; pedicels of the lateral spikelets to 0.5-1.2 (usually 0.5-0.8) mm. long, those of the terminal spikelets to 3 mm. long, scabrous; spikelets 2-3.5 (usually 2.5-3) mm. long; glumes about equal to (sometimes shorter than) the floret, the second a little longer than the first, glabrous to scabrous (mostly scabrous), rounded at the tip or blunt, rarely acute except in the longer spikelets, awnless, strongly I-nerved; lemmas to 3 (mostly 2.4-2.6) mm. long, glabrous or rarely puberulcnt at the base, mostly rounded at the tip, 3-nervcd (the nerves purple), awnless or rarely with awns as much as 4 mm. in length; palea n little shorter than the lemma, glabrous or occasionally with a few minute hairs at the base between the purplish keels. Holotype in the U.S. National Herbarium, no. 998949, collected in 1847 by Ferdinand Lindheimer in Texas. Only the number 725 is given, this being the number of the "Plantae Lindhcimcrianae" series. According to Blankinship (1907) this represcnts Lindheimer's own collecting number of 465 (fase. IV) and WitS collected in Fried­ erichsburg (now Fredericksburg), Gillespie County, Texas, in September 1847. Isotypes at F, GR, MO, and UC. DISTRIBUTION: Dry sandy or limestone soil, in draws of hills and open areas. Of limited distribution in south-centml Texas and Coahuila, Mexico. SODERSTROM-PODOSEMUM AND EPICAMPES 127 UNITED STATES: TEXAS: Southern Texfl.8, Lindheimer, in 1849-51 (NY); Neallc1l. in 1889 (OlI). Foothills, upper SeeD, Reverchon 1610 (F, MO, NY, TEX, US). Glen Rose Hills, Tharp 46293 (TAES, UC), Tharp, Dec. 7, 1928 (MO, NY, SMU). B AN DERA COUNTY: N. of Medina, Parkl &: Cory 24422 (TAES). W.-NW. of Bandera, Shinners 16880 (SMU). BELL COUNTY: Max­ da.le, Wolff 2632 (TAES, US), BEXAR COUNTY: Onion Creek, near San Antonio, Brown 3487 (TEX). Pleasanton Road 15 mi. S. of San Antonio, Burr 513 (NY). Cibolo Creek, LiI .. 17 (TAES). North Loop, Si/v,u. 11 (TEX, US), 355 (TEX, US). 20 mi. NE. of San Antonio, Silv.u. 354 (MICH, TEX, US). BURNET COUNTY: NE. of Lake Buchanan towMd Lampasas, Whilehurat, Nov. 21, 1956 (LL). CO MAL COUNTY: Comanche Spring, New Braunfels, etc., Lindheimer 1255 (ARIZ, F, GH, NY, TEX, UC, US). COMANCHE COUNTY ; Comanche Spring, Lindheimer 176 (CAS, ILL, MO, TAES). EDWARDS COUNTY: Barksdale, Palmer 11004, in 1916 (MO, US); Parks &: Cory 26893 (TAES). GILLESPIE COUNTY: Fredericksburg, Thurber 68 (NY). Lindheitner 465, = Plantae Lind­ keimerianae 725 (US holotype, F, GH, MO, UC, isotypes). HAYS COUNTY: Reagan Houston Ranch, Johnaon 360 (TEX). KENDALL COUNTY: N. of Comfort, Cory 20732 (GR, UC); Park. &: Cory 20729 (TAES), 20730 (TAES), 20731 (TAES). Spanish Pass, Palmer 10859, in 1916 (US). Comfort, S.lvem 7334 (CAS, DS, SMU, TAES, TEX). KERR COUNTY: Kerrville State Park, Cory 50506 (OS, GR, NY, SMU, TAES, TEX, UC, US). 25 mi. NW. of Kerrville, Gould 8468 (8M U, TAES, UC). 8W. of Kerrville, Parka &: Cory 24840 (TAES). KIMBLE COUNTY: NE. of junction OD Mason Highwa.y, Landers 5223 (TAES). KlNNEY COUNTY: W. of Bracketville, CorreU & CorreU 24740 (LL). NASON COUNTY: N. of Mason, Rea-rdon 23 (TAES). REAL COUN TY: W. Fork of West Frio Hiver, Cory 43240 (S~l U, TEX). N. of Leakey, Parks &: Cory 27385 (TAES). TRAVIS COUNTY: Austin, Bodin, Oct. 20, 1891 (DS). Oak Hill, Rogers 6520 (TEX). Barton Creek, Austin, Tharp 70 (TEX, US). Edwards Plateau, Tharp 3076 (US). Watkins Ranch, Tharp 49009 (US); Tharp, Roger., Wilkins, Cawan, Clark &: Jeffrey 49004 (TEX, US); Tharp.1 al. 51-516 (TEX). Austin, Warnock W1065 (TEX, US). WILLIAMSON COUNTY: Georgetown, Bodin 287 (NY). MEXICO: COAHUILA: About 24.5 mi. SW. of Piedras Negras, Reeder &: Reedu 3921 (US, YU). 8 mi. W. of CUlItro Cienegas, Reeder &: Reeder 3945 (US, YU). Muhlenberuia lindMimeri is distinguished by the decurrent ligule, long spikelets with glabrous lemmas, the glumes equal the floret, and the long-attenuate firm blades somewhat arcuate when old. It appears to be most closely related to M. involuta and M. pubi{Jluma. The former differs in having basal sheaths somewhat compressed but not keeled and gillmes shorter than the floret, the latter in having puberulent glumes and lightly villous lemmas. 6. Muhlenberilia pubigluma Swallcn. Proc. BioI. Soc. Waah. 56:78. 1943. Strongly caespitose perennial; culms stout, glabrous, about 75-125 cm. tall; nodes 3, pllbescen t below; basal sheaths compresscd­ keeled, glabrous, tightly imbricate, the old basal sheaths firm, dark brown, not becoming fibrillose; ligule decurrent, firm and brown at the base, becoming membranous for the greater part of its length, 5--13 mm. long, longer on the innovations; sheath auricles lacking; 128 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM hlades of the culm to 35 cm. long, nurrow, pILle green, firm Rnd conduplicl1te, long-attenuate to a firm brown point, 1-2 mm. wide when lint, the upper surface of the blade scabrous, benring a tight dense mat of tiny white hairs, the lower surface scabrous; upper thront hearing a dense mat of short appressed hairs; colltlr scaberulolls. Pnnicie erect, narrow, the branches appressed, interrupted below, olive to gmyish green, 20-34 cm. long, 1-2 cm. wide; axis scabrous; lower primary branches 4-5 cm. long, the secondary branches to 1.5 cm. long, tertiary branches lltcking; pedicels much shorter thun the spikelets, scabrous; spikelets 2.5-3.5 (averaging 3) mm. long; glumes rounded at the tips, mostly longer than the floret, the second "little longer thltl! the fif8t, hyaline, nerveless or indistinctly I-nerved, lightly pubescent, RIVIlless; lemmas 2.9-3.1 mm. long, RCUte lit the tip, indistinctly 3-nerved, awns 0.5-3.5 mm. long, the lower two­ thirds lightly villous, the upper one-third scabrous, the has nl margins more densely villous; palea a little shorter than the lemma, pubescen t on the lower two-thirds between the keels. Holotype in the U.S. National Herbarium, no. 2209360, collected in shrub zones of lower canyon where common, Sierrn de In ~fudefl1, C"ilon del Agua, Municipio de Cuatro Cienegas, Sept. 10, 1939, hy C. H. Muller (no. 3264). DISTRIBUTION: Known only from five collections made in cRnyon< of Coahuila and Nuevo Le6n, northern Mexico. MEXICO: COAHUILA: La Cueva, Corte Blanco fork of Charrctcra Canyon, Johnston 9072 (Gff, :MEXU, 1\(0). Ca~on df'l Agua, :\[unicipio de Cuatro Ciencgas, .Muller :l264 (US holotypc, OH, ue, i~otypcs). San I,orenzo Canyon, 6 mi. SE. of Saltillo, Palmer 401, in 1904 (F, GH, ;\10, NY, UC, US), NUEVO l.E6N: Between JJa Soledad find Escollfiida, Beetle M-406 (Ue). 14 mi. W. or Doctor Arroyo, Shreve &: Tinkham 96;')1 (GIO. Muhlenbergw puh;g/uma is distinguished by the brofidly decllrren t ligule, puuerulent glumes and li!(htly villous lemmas. In the original description, the author relnted this species to M. pubeseens (H.RK.) Hitchc. (= llf. di. lans Swollen, aceording to the present trentment). Tha.t species, however, does not have the narrow, firm, pale green, somewhat arcuate blades or broadly decurrent, firm fit the base, ligules, characters thut indicate" closer relationship to M .. lindheimeri and M. involuta. 7. Muhlenbergia mac:rotis (Piper) Ilitchc. N. Amer. FI. 17(6):463. 1935. Afuehltnbergia dialichophylla var. mutica Scribn. ex UrI,illR. Cat. Pl. l\.Iux. 39:3. 1897. Nomen nudum. Of the two collections listed, P ringle 23GO= M. macrotis, and Pringle 5f177= M. versicolor. Epicampes macrotis Piper. Proc. BioI. Soc. 'Vashington 18: 141. 190;). Basis of ~fuhlenberfJia macrolis (Piper) lIitchc. (Rosc 3!)28, Zacuu'cR$, !\·fcxico.) SODERSTROM-PODOSEMUM AND EPICAMPES 129 Epicampfa minutijlora Mez. Repert. Sp. Nov. Fcddc 17:212. 1921. Basis of MuhlenbeTgia meziana Hit.chc. 1935, not of AI. minuHftora (Michx.) lIitcho. 1896. (Lan{Jla88~ 750, EI Canizai, flMichoacan et Guerrero," l\..fcxico.) Afuhlenbergia meziana llitchc. N. Amer. Fl. 17(6) :461. 1935. Based au Epicampes minuliflora 1\lcz. Strongly caespitose perennial; culms narrow to very thick, glabrous to scaberulous, lY.-2Y. meters tall; nodes 3-5, glabrous, or sometimes pubescent below the nodes; basal sheatbs compressed-keeled, gla­ brous, the old basal sheaths brown, persistent, becoming frayed; ligule membranous throughout, lacerate from the base or near the base, 3-15 (usually 5-8) mm. long; sheath auricles 1- 10 (usually about 3) cm. long, the auricles of the sheaths higher on the culm often longer than those of the lower ones, straight or strongly twisted; blades of the culm very long, as much .LS 95 cm., becoming fine and threadlike at the tip, mostly folded, 2-6 mm. wide when fiat, the blades at the base narrower than the sheaths, edges of the blades saw-toothed, tbe upper surface scaberulous to scabrous (mostly scab­ rous), tbe lower surface scabrous; upper throat scabrous; collar glabrous. Panicle erect, columnar, tbe bmnches numerous, appressed, gen­ erally interrupted below, Iigbt green to whitish green, 25-65 cm. lung, 1.5-6 cm. wide; axis scaberulous to scabrous (mostly scabrous), the primary branches 5-12 Clll. long, the secondary brancbes to 4.5 cm. long and spikelet-bearing to the hase, tbe tertiary branches to 1 cm. ill length; pedicels 0.3- 1 mm. long, shorter tban the spikelets, scabrous; spikelets 2-3 mm. long, rarely as sbort as 1.5 mm. or longer than 3 mm.; glumes equal, usually longer than the floret, glabrous to scaberulous (mostly scaberulous), rounded at the tips, awnless, bya­ line, white or whitish green, nerveless or obscurely I-nerved; lemmas 1.8- 2.5 mm. long, acutish, indistinctly 3-nerved, awnless or rarely cuspidate, completely glabrous, even on the lower margins, at most the surface punctate; palea equllling the lemma or rarely a little longer, glabrous. Holotype in the U.S. Natiomu Herbarium, no. 302505, collected in the Sierra Madre, Zacatecas, Mexico, Aug. 17, 1897, by J. N. Rose (no. 3528). DISTRIBUTION: Moist shaded canyon slopes, ravines, banks above streambeds, moist ditehes, and wooded hillsides, at elevations of 6,000-7,000 feet. Common from Sinaloa and Durango, south to Guerrero and Oaxaca, Mexico. A single specimen has been collected in Guatemala. MEXICO: SINALOA: M&%D.tlan, Ortega 5075 (US). DURANGO: Sierra Tree Picas, Gentry 5312 (ARIZ, DS, hIO, NY) j /larvey 5312 (GR). 23 mi. SW. of 130 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM Buenos Aires, Reeder & Reeder 4218 (US, YU). ZA CATECAS: Sierra Madre, Rost 3528 (US holotypc). NAYARIT: La Barranca, Jones 23445 (CAS, :MO, NY, POM). SINALOA-NAYARIT: San Ignacio, San Javier, Ortega 1204 (l\l1~ Xl:). JALISCO: TepatitM.n-Guadll.iajara, Hernandez, Ruppert, &: Guevara X-2669 (US). SW. Autllin, Herntmdez X . 4641 (CHAP). La BarrnncR, Gundnlajam, Jones 27656 (POM), 27677 (DS, MO, NY). Orenduin, Jones 2767 (UC). Nevndo de Colima, llJcVaugh 10170 (l\llCII). Sierra del Tigre, 3 mi. S. of !"Iazumitla, Me Va ugh 13085 (SMU, US). 1-2 mi. E. of Tapalpn, MeVaugh 20519 (~nCII, US). Real Alto, Trail to l'ranquillns, Mexia 1713 (CAS, DS, F, Gil, MICH, MO, NY, UC, US). Guadalajara, Pringle 2360 (AHlZ, CAS, F, GH, MICH, NY, TAES, UC, US), 2356 (F, Gil, MO, NY, UC, US); Soderstrom 613 (US), 614 (US). GUANAlUATO: Dug", in 1897 (F). Ca. 8 mi. W. of San Felipe, Cerro del Fraile, Sohns 452 (MICH, MO, US). PUEnLA: Mcxique-Acatzingo, District de Tcpcaca, Nicolas, July 7, 1909 (F). DISTRITO FEDERAL: C. de Progreso, Matuda 19676 (MICH). MIeHoA e.(N: QUineeo, ArsIne 3218 (Gil, ILL, MO, NY, US). Lorna Sanla M.rfa, Arscne 8581 (MO, US). Cerro San Miguel, ArsCne 9937 (1\10, US). Alzimba Nalional Park, B" tl, 111-128 (US). Zacapu, Hernandez, Ruppert, & Guevara X- 2822 (US). 18 mi. E. of l\1orelia, King & Soderatrom 5011 (MEXU, MICII, SMU, TEX, US). 8-10 mi. NW. of C. !lidalgo, Me Vaugh 9925 (MICH, US). Pat1.cu.ro. Seier 1227 (G", US). Quiroga, Soderstrom 552 (US), 555 (US); Sohns 806 (US). GUERRERO: Pctlucalu, Mexia 9098 (CAS, F, GIl, MO, NY, UC, US). Between Ayusinll.p!l. and Petatian, Nelson 2122 (US). "AhcHOAC.\N ET GUERRERO": El Caniznl, IJangiasd 750 (CH, US, isotypes of At. meziana). OAXACA: Hlo Grande (N. of Niltcpcc) to Finea liLa Gloria," Ilernandez & Sharp X-1257 (US). GUATEl\lALA: HUEHUETENANGO: 10 km. W. of Agutlcn.tau, Williams, Molina, & Willi.,n. 21844 (US). Muhlenbergia macrotis is di,tinguished by the prominent sheath auricles that attain" length of 1 cm. or more (as much as ]0 cm. in Herndndez X-4641!) and in the mostly glubrous and awnless ur cuspidate lemmas. It is closely allied to M. disticlwphylla which hIlS long auricles, hut the lemmllS belU' a tiny tuft IIf hairs (uward the base of the margins and are usually lung-awned. Tbe euhns and panicles of M. macrotis are usually thicker and more robust than in M. distichoJihylla. Comparison may aho be made with M. robusta, but that species hils only rudimentlLry sheath auricles and the lemmas, although mostly glabrous, sometimes ha"e sparse short hairs Ilt the b""e. Muhlenberqia macrotis was originally described by Piper in 1905 as an Epicampes from a specimen collected by Rose in Zacatecas, Mexico, in 1897. It was known only from the type collection. Hitch­ cock transferred E. macrotis to ilfuhlenberqia in 1935, at the same time he transferred E. minutijlorlts to tbe genus naming the latter M. meziana. Muhlenbergia meziana Hitchc. is considered I\.S synonymous with ilf. macrotis in tbe present treatment. The original description of the former characterizes a specimen witli very long fillrides (to 45 rum. SODERSTROM-PODOSEMUM AND EPICAMPES 131 in length), flat blades to 4 mm. in width, a dense panicle, and spike­ lets 2.5- 2.75 mm. long. The collection listed by Mez in his description of Epicampes minutijloT'us is "E. Langlassc, bei El Canizal, MichoacAn (Mmoco)," without collection number. The specimen in the U.S. National Herharium marked as the type is E. Langlasse, no. 750, El Canizal, Michoacan. This specimen, however, does not agree in all respects with the original description, for the auricles are less than 1 cm. long and the spikelets are 2-2.5 (averaging 2) mm. long. This leaves some douht as to the collection Mez had in mind when he described E. minutijlo1'U8. Nevertheless, the completely glabrous lemmas, the white, almost translucent glumes, and relatively long auricles place it with other specimens of M. meziana. The type appears, therefore, to be an aberrant representative of the species. The holotype of M. macrotis agrees with M. meziana, with the exceptions that the spikelets are often a little longer and the florets exceed the gillmes in length. The gll.lmes, however, are 2-2.5 mm. long, rounded, ahoost translucent, and nerveless, like those of M. meziana specimens. Many of the spikelets in the panicle of the holo­ type of M. macrotis are diseased. I have noticed that in diseased panicles of other Muhlenbergia species the florets often become longer than normal, exceeding the glumes where the florets were normally contained within them. This perhaps explains why mlUlY of the florets arc so long in the spikelets of the type specimen of M. macrotis which, in other respects, is similar to specimens of M. meziana. Specimens similar in general to the type collection of Muhlenbergia meziana occur in the same geographic region where the type of M. macrotis was found, and therefore it seems likely that the holotype of M. macrotia was only a diseased specimen of the species later described as M. meziana. The follm>ing list, a comparison of the major characters of specimens of M. meziana and tbe holotype of M. macrotia, illustrates the similarity. height culm surface node surface sheath surface upper throat collar blade width upper surface of blade lower surface of blade ligule length M. meziana 125-230 em. mostly glabrou8 glabrou8 to slightly pube8cent glabrous scabrous glabrous to scaberulous 2-6 (mosUy 3-4) mm. scaberulouB to scabrous (mostly scabrous) scabrous 3- 13.5 (usually 5-8) mm. M. fIIacr«iI 134 em. glabrou8 glabrous glabrouo 8Cabrou8 gla.brou8 4-5 mm. scaberulous scabrous 11 mm. 132 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM auricle length panicle length panicle width panicle color axis surCace length of panicle branches: • pmnary secondary tertiary spikelet length glumcs glume length glume surface lemma length lemma surface awn length .\t. mafantJ \-7 (usually about 3) em. 26-65 em. \ .5-6 em. light green or whitish green sca.bcruIouB to scabrous 5-\ \.8 em. \-4.5 em. to ca. 1 em. 2-3 mm. equal, sometimes less than floret 2-3 mm. glabrous, nerveless or rarely obscurely 1-nerved \.8-2.3 mm. glabrous usually Incking. lemma. rarely cuspidate M. maaoti.t to 3.5 anci 4 em. 38 em. 1.5 em. greenish tan (old panicle only) scabrous 7 em . 2 em. la.cking 2.5-3.6 mm. equal, usually less than Ooret 2-2.5 mm. glabrous, nerveless ca. 3.2 mm. glabrous la.cking 8. Muhlenberg'. dlsUchophylla (J. S. Pres!) Kunth. Rev. Gram. Supp. xvi. 1830. Podosaernum distichophyUum J. S. Presl. ReJ. Haenk. I: 231. 1830. (Mexico : wi thou t precise locality, Haenke 173). Epicampes atricta var. distichophyUa (J. S. Prest) Jones, Cont.r. West. Bot. 14:6. 1912. Based on Podosaemum didichophyllum J. S. Pre~1. Muhlenbcrgia angu.tifo!ia Swallen. N. Amer. FI. 17(6): 457. 1935. (Mexico: Jalisco, Pringle 2346). Caespitose perennial; culms stout, glabrous, 1-1.75 m. tall; nodes 4, glabrous or somewhat puberulent beneath; basal sheaths compressed­ keeled, mostly glabrous, sometimes scaberulous; ligule membranous throughout, entire at the base and lacerate above, or finely lacerate throughout, 4-8 mm. long, longer on the innovations; sheath auricies 4-8 (usually 6-8) mm. long, the auricies of the upper cllim sheaths longer than those of the lower; blades of the culm to 90 cm. long, long­ attenuate, becoming threadlike at the tip, flat or folded, 1.5-4.5 (mostly 2-2.5) mm. wide when unfolded, narrow in comparison with the sheaths from which they dep"rt, the upper surface of the blade scaberulous to scabrous, lower surf/we scahrolls, the edges of the bill.des minutely saw-toothed; upper tbroat scabrous; collar glabrous to scab­ rous (mostly scaberulous). Panicle erect, somewhat lax at the tip, light green to tan (rarely • purplish), the branches spreading widely, 35-60 em. long, to 5 em. or more in width; axis scaberulous to scabrous (mostly scabrous), the lower primary branches 6-13 em. long, the secondary branches 1-6 em. long, the tertiary brunches 0.5-2 cm. long; pedicles of the lateral SODERSTROM-PODOSEMUM AND EPICAMPES 133 spikelets 0.2·-0.8 mOl. long, those of the tcrminlll spikelets to 2 mm., glabrous to scaberulous (usually sCl1berulous); spikelets 1.5-2.5 (usually 1.7-2) mm. long; glumes longer than the floret, the first glume often a little longer than the second, glabrous to scaberulous, broadly acute, awnless, hyaline, nerveless; lemma 1.4-2.5 (usually 1.7-2) mm.long, glabrous throughout except for a tuft of short hairs at the base of tbe margins, rounded at the tip, 3-nerved, the middle nerve becoming purplish and thickened toward tbe tip, excurrent as an awn 4-16 mm. (usually 1 cm. or more) in length; palea equal to or slightly shorter than the lemma, glabrous. Fragment of type in the U.S. National Herbarium, collected in Mexico, without precise locality, by Haenke (no. 173). D'STR,BUT'ON: Rocky hills and exposed areas of oak woods, at ele­ vations of 1,500-7,500 ft., from Jaliscu, Mexico, southeastward into Guatemala. Apparently infrequent. MEXICO: Haenke 173 (US fragment of type of Podo.aemum di8tichophyUum, ex W). hLlseo: narranea de Oblatoo, Hitchcock 7335 (NY, US). SW. of La Resolana, road to La Huerta, MeVough 21106 (MICH, US). Above (N. of) La Cuesta, road to Talpa de Allende, MeVough 21224 (MICH, US), 21225 (MICH, US). Guadalajara, Pringl, 2346 (GIl, NY, UC, US, isotypes or M. angmti/olia) . MEXICO: Tejupilco, TemascaJtcpec, Hinton 2719 (GH, LL, NY, US). Luviano8. TemMe.ltepee, Hinton 5302 (ARIZ, NY, US). Amatepec, Mat.do 29874 (US), 29875 (US). "MlcnoAcAN ET GUERRERO": Sierra. Madre, Langlasd 607 (GH, US). Cerro Mamegai, Langlas8l 674 (GH, US). GUERRERO: Carbonerwt-Filo Mayor, Hinton 9910 (MICH, US). Vallecitos, Hinton 11635 (ARIZ, LL, MO, NY, US). 15 mi. N. or Tierra Colorado, Reed" &: Reeder 4159 (US, YU). CHIAPAS: EscuinUa, ,Matuda 319 (MICH, US). Mt. Ovando, Motuda 322 (MICH, MO, US). GUATEMALA: HOEHUETENANGo: E. of San Scbastl~n, Standley 81480 (US). Near crossing of RIo San Juan IxM,n, E. of San Rafael Petzal, Standley 83016 (US). W. of Huehuetenango, Williams, Molina, ~ William8 22309 (US). Muhlenbergla distichophylla is dint below usually glnbrous scabrous sClI.berulous to scnbrous (rurely glabrous) 1.5- 4.5 mm. 37-91 em. scaberulolls to scabrous scabrous membranous, lacerate 4- 8 mm., sometimes more 0.2-4.5 ern. 30- 58 em. usunlly 3.5-5 em. sCftberulous to scabrous (mostly scabrous) greenish tan 6-12 em. l.6 em. 0.2 em. 1.5-2.5 mm. glabrous 1.4-2 mm. .\1. anguuifolia holotnlC 111-130 em. glabrous glabrous to pubcruk-nt below glabrous sCftberu)olls or scabrous glabrous 1.5- 2 mm. 48 em. glabrous or scaberulous scabcrulous t.o scnbrous mcmbranous, la.ccmtc 6-14 mm. 1.7-3 em. 30-4S em. 2-2 .5 cm. scabrous light green 4-6.5 em. 1.5 em. lacking 2.2-2.5 mm. glnbrous 2.1-2.3 mm. glabrous except (or hairs toward the base o( the margin!'! (in both) 4.5-16 mm. 8-9 nlln. 9. Muhlenbergia versicolor S\'\"allcn. Contr. U.S. Nat. Herb. 29: 412. 1950. ft{ueklenbergia dislicltophylla var. mulica Scribn. ex Urbina. Cat. PI. Mex. 393. 1897. Nomen nudum. Of the two collections listed l Pringle l 2360 = M. macrotis, and Pringle 5577 = M. versicolor. Caespitose perennial; culms glabrous or somewhat puberulent, 82-199 (mostly 100-150) em. tall; nodes 3 or 4, glabrous 01' pubescent below; basal shenths compressed, but not strongly keeled, the old sheaths brown and somewhat fibrillose; ligule membranolls throughout, 5-22 (usually more than 10) mm. long, usually flanked on either side by auricles that become membranous and twisted abo\'c, the firm , brown base of sllch auricles usually 4-8 mm. long; blades of the middle of the culm shorter than those of the lower pfil't, 12- 27 em. long, usually folded, 2-5 mm. wide when flat; upper surffice of the blade seaberulous to scabrous, the lower surface scabrous (lower surface usually scabrous find the upper surface scaberuJous); upper throat scaberulous to scabrous; collar glabrous to puberulent. SODERSTROM-PODOSEMUM AND EPICAMPES 135 Panicle erect, narrow, the branches IlScending, lead green to purplish green, 17-60 (usually 20 40) cm.long, \.5-6 cm. wide; axis scaberulous to scabrous; primary branches 4-11.5 cm., secondary branches \.5-3.5 cm. long, tertiary branches lacking or to 0.5 em. long, when present; pedicels of the lateral spikelets 1-2.5 mm. long, those of the terminal spikelets relatively long, to 3-5 mm. , the pedicels glabrous on the lower part, becoming scaberulous on the thickened part below the spikelet; spikelets 2.5-3.5 (lIsllally 3 or more, rarely to 4) mm. long; glumes I1sllally a little shorter than the floret, the second glume longer than the first, the tips erose (IInder high power) or awn-tipped, the aWlls to 1.2 mm. long, frequently only the second gllme awned Ilnd the first acute, usually scaberulous (rarely glabrous), hyaline, nerveless or faintly I-nerved; lemmllS neute, 2.5-3.5 (mostly abollt 3) mm. long, 3-nerved, villous over the lower half or two-thirds of the bSLCk on and between the nerves, and more densely so on the margins, awn 17-30 mm. long, flexuous; callus of lemma long-pilose; palea equaling or a little longer than the lemma, moderately to densely villous between and, sometimes, on the keels. Holotype in the U.S. National Herbarium, no. 1961991, collected about 170 kilometers north of Oaxaca City, Oaxaca, Mexico, Decem­ ber 13, 1945, by Efralm Hernandez Xolocotzi and J. A. Jenkins (no. X -810) . DISTRIBUTION: Rocky mountainsides and ledges, and slopes of barrancas. Rather IIncommon, ranging in Mexico from Michoacan and the state of Mexico southeastward to Honduras. MEXICO: OUANAJUATO: NE. of Cd. OuanRjuato, Reeder &- Reeder 3095 (YU. PUEBLA: Zapotitlan de Ins Salinas, SE. of TechuacAn, Hernandez, Oct. 27, 1960 (CtIAP, US). Zapotit1~n, near Tchu.c&n, He .. , Oct. 1906 (US). Between ApaJa and the top of Cerro Chichiltcpce, Smith, Peterson, &; Tejeda 3879 (US). MORELO.: Sierra d. Ocuila rumbo Moxie.pa, Lyonnet 2873 (US). Valle de Tepeitc, Lyonnet &: Elcoro 1838 (US). VERACRUZ: Maltrats, Kerber 226 (US). MEXICO: Rinc6n, Temascaltepec, Hinton 2081 (MO, NY, US). Socab6n, Temascaltepec, Hinton 2324 (OH, LL. MICH, NY, US). Tejupileo, Temgeeal~ tepee, Hinton 2719 (OlI). Sultepee, },fatuda 26615 (US). Ixtaccihu.t1, Purpm 1611 (ILL, MO, US). Saito de Agu., Purpu. 1629 (US). 4 mi. S. of Tenan­ eingo, Reeder &; Reeder 4168 (US, YU). DISTRITO FEDERAL: Lomas de Tacubaya, Gfindara, in 1938 (US). Villa Guerrero, Tateoka 1119 (US). MrcBoAcAN: Lomas de I. tIuert., Ars",e 2465 (!LL, MO), 2465H (F, US), 2825 (MO, NY, US), 5438 (NY, US), 5446 (ILL, 1'010, NY, UC, US), 5851 (MO, US), May 30, 1909 (US). Punguato, ArB!n. 2674 (US). Ccrr08 de San Miguel, Arsine 5304 (NY, US), 6803 (US). Lorn, Santa Mari., A""'e 8585 (MO, US). Along road from Teitzio-Tiquicheo-Huetamo-Altamira, Sohns 880 (US). GUERRERO: Teotepec, Mlnn, Hinton 14803 (ARIZ, ILL, LL, NY, TEX, US). OAXACA: Ca. 170 km. N. of Oaxaco City, Hern~nd.z & J enkin. X-810 (US holotype). hUan de Ju:irez, KrueQer & Gillu pi. 25 (CAS, LL, MO) . Mina de Dolores, near Tal ... LUbmann 673 (US fragment), 984, in 1841-43 (US). MecoatlAn, S. Andr~., Liebmann 736 (US fragment). Dolores, Liebmann 737 (MO, US). Reyes, Nel.on 1780 (US). 221-352--67 5 136 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM (?)Sierra de San Felipe, Pringle 5576 (GIl, MEXU, US), 5577 (US); (?)Smith 927 (in part) (MO, NY, US). Tcmuscnlapa to San Ildefonso de Villa Alta proper, Santos 3530 (NY, US). 45 mi. N. of Oaxaca, Soderstrom 417 (US). CHIAPAS: Between San Crist6bal Las Casas and 8nn Gregorio, Hernandez &: Sharp 534 (US). B~trranca Honda, Siltepcc, Matuda 4124 (GH, LL, 1UCH, NY). GUATEMALA: HUEHUETENANGO: Aguacattin road, 10 km. E. of Hue­ huetenango, Standley 82073 (F, US). Between San SebastitiH II. and large pefiasco above town, Steyermark 50504 (F, US). Barranco "Palo Negro" about 10 km. W. of Aguncatan, Wilhams, Molina, & Williams 21850 (US). SAN MARCOS: San Marcos, Lehmann 1578 (US fragment, ex (;). SOLOL..\.: Lugo Atitl:in, de Koninck 146 (US). HONDURAS: MonAz.(N: Suyapa, S,rallcn 11277 (US). Muhlenbergia versicolor is distinguished by the long ligule und lIslIlllly short sheath auricles, the nurrow, densely flowered dnrk green or purplish-green panicles, the spikelets over 3 mm. long, the lemmas long-awned and villous over most of the surface on nnd between the nerves. It appenrs to be most closely related to 111. cmersleyi, and most herbarium specimens have been determined as that species. Although the two are similnr in huving long ligules and pubes­ cence on the long-awned lemmas, they are easily separated. In M. verswolor almost the whole lemma is sparsely to densely villous on and between the nerves; in AI. emerslcyi the puhescence is confined to the rnidnerve and margins. 'I'he sheaths in M. 1)ersicolor are charncteri7.ed llslIally by short auricles but these fire lacking in AI. emersleyi. The spikelet is dark green or purplish green in M. verswolor, bllt lighter and mnst often pmplish or tan in 111. emersleyi. Specimens of Epicampes (Smith 927; Pringle 5576, 5577) collected on the summit ledges of Cerro de Sfin Felipe (nbove the city of Oaxaca, at an elevation of about 10,000 ft.) fire without doubt allied to M. versicolor. The base of the plant, the lend-green panicles, long spikelets, nnd villous lemmas nrc chnracteristics of M. versicolor. 1'hese specimens, however, pxhihit some fundamental differences from the typical plants: The glumes are blunt rather than acute or dentate and awn-tipped fiS in M. ,'er8;c%r; the aurides of the sheaths aro very long, 1-3.5 cm., those of M. versicolor being less than 1 em. long; the panicles are narrower, shorter, and the branches morc appressed. In one specimen the lemma..;; nre a,vnlcss, but long-awned in others, fiS in typicnl 111. versicolor. When more information becomes available from fiddit.ionnl field studies on Cerro de Sun Felipe, this curious group of specimens may prove to represen t a distinct species. 10. Muhlenbergia gigantea (Fourn.) Ifitehc. N. Amer. FI. 17(6) :461. HJ3!'i. Epicampcs expansa Fourn. J\1t'x. PI. 2:88. 1886. (floitrTi 104 in part [Botteri &: Sumichrast 104], Ol'izahn [Vt'racruz], l\1('xi('o. Botleri 104 in part is also cited by Fournier under Epicampes mutica Rupr. ex Fourn.) SODERSTROM-PODOSEMUM AND EPICAMPES 137 Epicampes bourgaei Fourn. Mex. PI. 2 :88. 1886. (Bourgeau 2973, Escamela pro Orizaba [Veracruz], l\Icxico.) Epicampes bourgaei vaT. tnutica Fourn. Mex. PI. 2:88. 1886. (Liebmann 676, 678 Mirador [Veracruz], l\.Icxico, and Liebmann 677, Tlaltengo [Veracruz], cited.) Epioompes laxiuscula Fourn. ·:!\lex. Pl. 2:88. 1886. (BoUeri 155, Orizaba (Veracruz], Mexico.) Epicampes gigantea Fourn. 1\1ex. PI. 2:88. IS86. Basis of Muhlenbergia gigantea (Fourn.) Hitcbe. (Bourocau 3137, Rio Blanco near Orizaba [Veracruz), Mexico.) Epicampe8 ehrenbergii Me •. Repert. Sp. Nov. Fcddc 17:212. 1921. (Type (rom Cuesta de Pinotca [Hidalgo?], ::\'1cxico.) This species was questionably referred to MuhlenbcToia Tabusia (Fourn.) lIitche. in N. Amer. Fl.17(6) :462. Although the type has not been seen, the description is that of M. gigantea for it states, in part: Hligulis magnis ... " (the ligule of M. rob1J.3ta is "ery short) and "Inftorescentia myriantha, bene thyrsoidea, 3 pinnatim palUli­ culata [sic] ... " (which must refer to the typicalJy large and widely spreading panicle of fttf. gigantea). Muhlenbergia alta Hitchc. N. Amer. FI. 17(6):461. 1935. (Hitchcock 7180, Jalisco, Mexico.) Muhlenb,rgia magna Hitchc. N. Amer. FI. 17(6) :460. 1935. (Pringle 3335, Jalisco, Mexico.) Strongly caespitose perennilll; culms stout and thick, robust, glabrous or somewhat seaberulous, 130-300 em. (mostly 1.5--2.5 m.) tall; nodes 3, glabrous below; basal shelltns stroDgly compressed­ keeled, glabrous or somewhat scaberulous; ligule membranous through­ out, generally undivided at the buse, becoming lacerate above, 1-3.5 (usually 1-1.5) em. long; sheath auricles lacking, rarely rudimentary ones present; blades of the culm 35-115 (usually more than 65) em. long, flat, the edges saw-toothed, 2.5--12 (usually 5--8) mm. wide, upper surface of the blade usually scaberulous, the lower surfaco seaberulous to scabrous, scabrous-ciliato on the margins near the ligule; upper throat scaberulou. to scubrous; collar glabrous (somf\­ times seaberulous). Panicle very large and open, the branches weak and lax and some­ what drooping or more rigidly flexuous, purplish or purplish brown, 45-110 (usually 50-100) em. long, 20-30 cm. or wider, the branches opening wide, long-naked below, the aggregates of spikelets borne on the tertiary and quaternary branches, the groups of bmnches borne distant from each other on the axis; primary hranches 11-27 (usually 15-20) cm. long, the secondary branches 1.5--12 (usually 4-10) cm. long, the tertiary branches 0.5-5.5 (usually 1--4) cm. long, quaternary branches, when present, to 2.5 cm. long; pedicels shorter than the spikelets, uSllally glabrolls (sometimes scab.rulous); spikelets 1.4-2.5 (mostly 1.5- 2.2) mm.long; gll1mes rounded or !lcutish at the tip, about equal, a little longer than the floret) gla.hnms or ~cllberllious, awnless, I-nerved; lemmas rounded or aClltish ot the tip, 1.3-2.2 (mostly 1.6-2) 138 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM mm. long, glabrous, 3-nerved, awnles., (the mid nerve sometimes be­ coming darker and thickened toward the tip and extending heyond it as a tiny point); palen, equaling the lemma, glabrous. Fragment of type in the U.S. N at.ional Herharium, collected in re­ gion d'Orizaha, Rio Blanco, Veracruz, Mexico, Sept. 30, 1866, hy BOlJrgean (no. 3137). DIs'rRlBUTION: Open rocky slopes and bllrmncas, Ilt elevations of 2,000-7,500 ft., most commonly found at ca. 3,500-5,000 ft. Known only from Mexico, ranging from Sinaloa and Durango southeastward to Chiapas. Apparently infrequent. MEXICO: SINALOA: E. of Santa Luera, Reeder &: Reeder 24RR (YU). Du­ RANGO: W. of La Ciudad (Ma1.atl{w-Durango rond), Reeder & Reeder 2522 (YU). JAI.ISCO : SW. Autl,ID, Herndndez 4M~ (CHAP). Znpotl~n, Hitchcock 7180 (US, holotype of M. alta), 7247 (11,1" liS) . Pucnte San Pedro, SW. of TecaliU~n MeVaugh 18096 (MICH). Gundulajora, Pringle 3335 (F, GH, NY, UC, US, jsotypes of }of. magna), 11738 (CAS, F, GH, MO, US). Sierra. Madre, W. of Bolafioe, llose 3002 (US). Guadalnjnrtl, Sodu3trom 607 (US, YU). VERACRUZ: Orizaba, BotteN 103 (US fragment, ex CGE), 104 (US fragment of type ot E. expans4, ex CGE). 159 (US fragment, ex CGE). Eacamcla, region d'Orizaba, Bourgeau 2973 (US fragment of ty~ of E. hourgaei, ex Pl. Oriroba, Rfo Blanco, Bourgeau 3137 (US fragment of type of E. giganlea, ex LE, P). Orizab:l., Cerro del Borrego, "Curso de ecologfa vegetal," Dec. 14, 1959 (CHAP). ~rango de Dn. Bartolo cnrretcra·Veracruz·C6rdoba, llernandez, Tapia, & Malthu8 SE-1482 (CHAP). Mirador, Liebmann 676 (US), 678 (US). OrizRb., "C. Mohr herbar­ ium" (US). Orizaba, Mt1Uer, in 1850 (NY). Veracruz a 22 km. de Cll.temaco sobre lAo cnrretcrn Acayucan, Tapia & .M artfnez SE-644 (CHAP). Loc.? von Rozynski, in H132 (1933?) (F, NY, YU). MEXICO: Cajones, Tcmnscaltepec, Hin­ ton 2386 (MO, NY, US). Vigna, TemnBCRltcpcc, Hinton 2626 (MO, NY, US). MICHO .O\C .(N: Pto. Cruces, Coalcoman, Hinton 12471 (ARIZ, GH, LL, MO, NY, TEX, US). 22 km. S. of Uruapan, King&: Soderstrom 4860 (MEXU, MICH, 8M U, TEX, US). Detween eharapengo and EI Guaco on road from Uruapan to Apatzinp;an, Moore, Hern(}.ndez & PorraJJ 5750 (UC, US). GUERRERO: Ma.ch6n, Mina, H1'nton 9635 (MO, NY, US). 13 mi. N. of Tierra Colorada, Reeder &: Reeder 4157 (US, YU), OAXACA: Cerro de San Felipe, ConzaUi 710 (GIl), Conzatti 2534 (US). TepenixUahullco, diet.rito de Tuquila, Conzatti 4376 (GH, US). Reyes, Nelson 1779 (CH, US). Tcmascalapa to San lldefonso de Villa Alta, district of Villa. Alta, Santo3 3531 (US). CHIAPAS: between San Geronimo and EI Pozo via Abasolo and El Retiro, Hernandez &: Sharp X-597 (US), Tuxtla. Guti~rrez, Tateoka 1103 (US). Muhlenbergia gigantea is dist.ingnishcd by its large size, robust culms, long ligule, large, wide-spreading panicles, and relatively sman glabrous spikelet.. It is most closely related to M. mutica and the type specimens of both are from Orizaba, Veracrnz, Mexico. The spikelets differ in tbe ratio of glume lengt.h to floret length: In !af. gigantea the glumes are about equal to t.he floret.; in M. mutica the glumcs exceed the floret by several millimeters. In the latter species SODERSTROM-PODOSEMUM AND EPICAMPES 139 the glumes are very acute, but more rounded or acutish in the former. This is possibly a variation within the same species, for the terminal spikelets of M. gigantea rarely have elongated glumes extending beyond the floret for several millimeters. An example is found in the type material of M. gigantea (Bourgeau 3137). The spikelets average 2 mm. in length, but in one case the terminal spikelet is 2.5 mm., enclosing a 1.5 mm. floret. As relatively few collections of M. mutica have been made, I do not feel safe in generalizing on the variability of the species at this time, and for this reason am not combining them. Additional field work, particularly in the region of Orizaba, Veracruz, will be necessary before this problem can be solved. Herbarium specimens of M. robusta are often confused with M. gigantea. When only a panicle is present, the wide-spreading habit is often not obvious in dr'ied condition. If vegetative parts are present, the short ligule and rudimentary sbeath auricles of M. robusta readily separate it from M. gigantea. Hitchcock (1935) described two new species from Jalisco, Mexico: Muhlenbergia magna (Pringle 3335) and M. alta (Hitchcock 7180). These specimens, like M. gigantea, are large robust plants witb long lacerate ligules, wide-spreading panicles, and glabrous spikelets. Muhlenbergia alta is described as differing from M. gigantea in its smillIeI' spikelets, 1.5 mm., as opposed to 2-2.5 mm. A study of tbe holotype of M. alta reveals that the spikelets actually range from 1.5-2 mm. in length but such variability also occurs in specimens referred to M. gigantea! The holotype of M. magna exhibits no basic differences from M. gigantea except for the more rigid and erect ,"'niclo branches. Color of t,he panicle is tbe only character used in the key to separate the two species (purplish in M. gigantea, brownish in M. magna). Many of tbe specimens available for study could not be placed satisfactorily on the basis of erectness versus laxness of panicle branches or on the color of the inflorescence. A striking example uf color difference was fuund in specimens collected in Durango, Mexico (J. &: C. Reeder 2522, yellowish brown) and Sinaloa, Mexico (J. <1\ C. Reeder 2488. dark purple). Both plants are similar except for color. The label of the former reads: "On a steep rocky slope. Both yellow and purple forms here." Within limits, characters such as spikelet size and panicle color and h"bit are variable in species of Epicampes and are not of specific magnitude. As M. magna and M. alta appear to represent notbing more than normal variation within 111. gigantea, they are bere com­ bined. The following comparison of characters of these three sup­ posed species illustrates their similarity: 140 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM M . ,1~'llca SI)CCllllc llS M . alro holo{Yllc ,\{. ma"na holutnK' height 160-300 em. 193 em. 172 em. culm 8Urracc glabrous glabrous glabrous node surface glabrous glabrous glabrous basal sheaths glabrous, glabrous glabrous compressed- comprcsscu- compressed-keeled keeled keeled upper throat scabcrulous to scaberulous scaberulous scabrous collar mostly glabrous glabrous glabrous (sometimes scabcrulous) blade width 4-12 (lIsuoUy 7- 9) G-9 mm. 3.5 (in other spcci- mm. m ellS 2.5-7) 10m. upper surface of glabrous to scaberulous glabrous to blade scaberulolls scabcrulous (mostly scabcrulous) ligule texture membranous, membranous, membranous, becoming becoming lacerate lacerate lacerate ligule length 5-35 mm. (usnally 6 mm. ca. 10 mm. 1 em. or more) sheath auricles lacking lacking lacking panicle lengt.h 45-110 em. 100 em. 46 em. panicle width 20-35 em. or Over 30 e m. 25 cm. morc, widely spreading axis surface scabcrulous scabcrulous glabrous to sca.bcrulous pedicel length 0.2-0.8 mm., less less than spikelet 0.4-0.7 mm., less than spikelet. than spikelet pedicel surface glabrous to glabrous scaberulous 5caberulous panicle color purplish (some- dark purple brownish times brownish) panicle bra.nches: • 1 ~-27 em. 25 cm. 14 cm. prnnary secondary 4-12cm. 11 em. 5.5 em. tertiary 1- 5.5 cm. 2 em. 1.5 em. quaternary to 2.5 em. - - glume 1st/2nd about equal equal C