PROCEEDINGS
OF THE
WASHINGTON ACADEMY OF SCIENCES
Vol. VIII, pp. 167-196. December 18, 1906.
A STUDY OF RHUS GLABRA.
By Edward L. Greene.
INTRODUCTION.
The genus Rhus as Tournefort restricted it two centuries ago,
and as many another systematist since his day has held it, is
clearly marked and easily denned. As to habit — that foremost
indication of a good plant genus — this generic type stands well
aloof from all its allies ; even distinctly apart from each and
every one of those kindred generic groups which, like Cottnus,
Toxicodendron, Metofiium, Lobadium, Rhoeidium, and Styftho-
nia, in another than the Tournefortian school of taxonomy, have
been thought of as preferably constituting mere subgenera of
RInts. But not a species in any of those other genera named
makes the least approach to typical Rhus in habit. Every species
and variety of this appears as a shrub or tree with few stout stag-
horn-like branches, each clothed heavily near its summit with
odd-pinnate leaves, these usually large and of many leaflets.
In our silva the only tree which in aspect recalls the sumachs is
that naturalized alien, the Ailanthus, a genus 01 no near affinity
to Rhus. But between the last and its near relative Schmaltzia
there is no habital resemblance. In this regard they are quite
as unlike as are currant bushes and elder trees ; and, as for
Toxicodendron, its habit is as remote from that of Rhus as the
habit of a grape vine or English ivy is remote from that of wal-
nut trees.
Over and above its marked habit, the characters by which this
Rhus of Tournefort establishes itself as a model genus are, the
Proc. Wash. Acad. Sci., December, 1906. 167
;
l68 GREENE
terminal origin of its inflorescence, the firmness and compactness
of that inflorescence, concurring with small red velvety or plushy
drupelets for fruits.
Of the genus, in this which seems to me the most reasonable
and natural acceptation of it, there exist in North America, ac-
cording to classic standards, four species, — Rhus glabra,
typhina, ptimila and copallina}
To the last of these there is attributed a geographic range
somewhat incredible for that of any one species of shrub of what-
ever genus ; almost incredible, I say, to any experienced student
of climatology as affecting plant life and the distribution of spe-
cies. But according to the books Rhus copallina occurs as one
and specifically the same in several widely sundered and very
different floral regions. It is said to be common in the hard soil
and severe climate of New England, and as much at home in the
subtropic lowlands of Florida, twelve hundred miles southwest-
ward ; even running away to the arid cactiferous hills of further
Texas that lie westward from Florida another thousand miles
and yet again, in a region so extremely different from either of
these as that of the Great Lakes in Minnesota and Wisconsin,
the same Rhus copallina it is said, recurs.y
An European celebrity more than twenty years ago, without
field knowledge of the shrubs, and with no experience in prob-
lems of North American phytogeography, but using the imper-
fect light of European herbarium material only, made out and
named a half dozen varieties and subvarieties of our Rhus copal-
Una;"1 all which work is ignored or suppressed by later Ameri-
can compilers of books ; to whom the following out of the vivid
suggestions of Engler would entail the expenditure of much time
and energy, whereas suppression is of all things the most easily
done.
Rhus copallina is one of many hundreds of North American
phytologic problems awaiting investigation and solution.
Another of our four species, namely Rims pumila, stands in
most marked contrast to the preceding in point of geographic
L Torrey & Gray, Flora of North America i : 217. Gray, Synoptical Flora 1 :
384-
2 Engler, in DC. Monographic Phanerogamarum, 4: 3S3.
A STUDY OF RHUS GLABRA 169
distribution. It is almost local, occurring nowhere but in lower
and middle districts of the Carolinas and Georgia.
Rhus lyphiua, the largest and most tree-like of our species,
ranges widely, at least when compared with R. pumila. It is cata-
logued for all the states from Maine to Georgia and Mississippi,
thence northward to Minnesota and the Dakotas, but is every-
where less common than R. glabra, and more particular than
either that or R. cofalliiia as to its environment. Everywhere
southward it is of the mountains or the hill country only, never
coming down to the lowlands or to the seaboard. Neither at
the northwest does it come out from its woodland habitat to
adorn the copses bordering the prairies where a subspecific ally of
R. glabra is so much in evidence. It seems to have little
adaptability to varying conditions other than those of heat and
cold ; though in this regard its adaptability is very marked.
The climate of Minnesota and the Dakotas, and that of Georgia
and Mississippi are extremely unlike as to temperature. Yet
between the Julius typhina of the most northerly locality and
that of the stations farthest southward, one does not discover
notable differences other than those of the size of the shrub and
the number of the leaflets. In other respects they seem to be
much the same ; so that the type is apparently one of a singular
degree of stability under somewhat varying conditions.
Concerning R/ius glabra, the type species of the genus as to
North America, one may note first of all its nearly universal dis-
tribution. In this regard it is most unlike any of its congeners
here. From beyond the river St. Lawrence northward, down,
to the very shores of the Gulf of Mexico, its range is across the
continent. Within these parallels, into every floral region be-
tween the oceans, however different — excepting only that of
California — there enters that which, according to the books
and lists of plants, is Rhus glabra.
There is no one species of tree or shrub of any continent
that really holds the geographic range which the books and lists
ascribe to Rhus glabra. By all the analogies of things there
ought to be several marked species or subspecies of this type in
the southern Appalachian region between Maryland and Ten-
nessee and Georgia ; another and an equally distinguishable set
iyo GREENE
between northern New England and the headwaters of the
Mississippi beyond Lake Superior ; another species or two pecu-
liar to that vast empire of the Middle West, the prairie country ;
as many more in that different and equally extensive stretch of
country lying between southern Missouri and the shores of the
Gulf of Mexico. Then, since there is a Rhus glabra all up and
down the two thousand miles' length of the Rocky Mountain
region, this ought to be thoroughly distinct by plenty of charac-
teristics, and to resolve itself naturally into a number of varieties
or subspecies. Just the same should be looked for in the shrub
accredited to another empire, that of the Pacific slope northward
lying between the sources of the Columbia and Puget Sound;
while the scores of isolated mountain ranges rising up out of the
deserts of Nevada, Utah, Arizona and New Mexico — for the
type in question is there also — should furnish another and pre-
sumably the most marked group of Rhus glabra segregates.
Our herbaria cannot to-day be supposed to be well supplied
with specimens representing this type. No author has investi-
gated it, and no special call has been made for the collecting of
these shrubs from different regions. Nevertheless, the mass of
material that has been before me during some months past is
amply sufficient to enable the investigator to point out characters
by which a number of species may be, and reasonably must be,
given recognition ; characters of foliage in abundance, and
characters of the fruiting panicle and the fruit itself.
Perhaps more trying than the task of examining and com-
paring specimens to find out specific characters, is the great
amount of bibliographic work that is necessary in order to
determine which one of the several eastern species ought to
bear the name Rhus glabra; for even this, as indicated —
though never described — by Linnaeus was an aggregate. In
the botanic gardens of Europe several species had been long in
cultivation, had been recognized as species and even described
as such, when Linnaeus in the middle of the eighteenth century
came along, and, bundling all the glabrous kinds together, named
not any one of them, but the whole bundle of species, Rhus
glabra.
If Linnaeus is to be credited with some one particular Rhus
1
A STUDY OF RHUS GLABRA 1 7
glabra that we must if possible segregate from the bundle of
species which bundle he so named, our task is one demanding
the very best skill of both the taxonomist and the historian.
EARLY HISTORY.
Prior to the discovery of America the Rhus of all botany was
a monotypic genus. It began and ended with Rhus carta)/a,
also by some authors called Rhus obsoiu'oruui, a shrub of the
Mediterranean region, well known in the useful arts from im-
memorial ages.
No second species of Rhus was known until as late as the year
1620, when Caspar Bauhin, publishing an illustrated quarto
containing names and descriptions of more than 600 new plants
from various parts of the world, brought to the notice of bot-
anists what he chose to name Sumach angustifolium} This
was known to have come from the New World, though in an
herbarium specimen only. Historically this is the earliest and
oldest element entering to the confused R. glabra Linn. Bauhin
himself in the year 1620 showed a preference for the Arabic
name Sumach, the exact equivalent of the Greek and Latin
Rhus ; but in his more comprehensive work of three years later,
the Pinax, as if having decided to use the Greek and Latin
rather than the Arabic name of the genus, he adopts Rhus,
renaming his new American species, Rhus augustifolia?
At the time of its publication in 1620, and long afterwards,
the material on which it was founded was believed to have been
derived from some island off the coast of Brazil ; but a century
later, no further specimens of it having been received from any
part of South America, and because of its now having come
to be known as certainly North American, the idea of its being
indigenous to Brazil was abandoned.
In so far as I have been able to examine early records, the
next mention of any American Rhus is in Banister's Catalogue
of Virginian Plants, published in the year 1688. That this was
some member of the group of R. glabra we are assured by his
note that the branches are glabrous. The one with soft hairy
1 Prodromus Theatri Botanici, p. 15S.
2 Pinax Theatri Botanici, p. 414.
172 GREENE
branches, R. tyfihina, was by this time well known by Bauhin's
description of it, and had perhaps already appeared in some
gardens in Europe. In 1726 both the hairy and the smooth
sumachs were to be found in some London gardens and parks,
and in 1732 Dillenius published a folio plate and a full descrip-
tion of what must apparently stand for the R. glabra Linn,
of 1753-
CHARACTERS FOR SEGREGATE SPECIES.
Linnaeus' statement of the characters of Rhus glab?'a reads
thus : " Leaflets pinnately arranged, lanceolate, serrate, glabrous
on both faces." This is the same as no description at all. If one
assume said compound leaf to be odd-pinnate rather than equally
pinnate, one does so without any warrant in any word that
author said about either the species or the genus. Equally
without warrant will be any assumption that the leaf is of 7
leaflets, or that it is of 17, or of 27. Linnaeus gives no hint of
its character in these most significant particulars. One will also
reasonably infer that the leaflets are not notably pointed at the
upper end ; and whether at base they be stalked or sessile you
have no means of judging. It must also be assumed that there
is no distinction of coloring noticeable respecting the two faces of
the leaf; also whether of a dark-green, or of a bright-green,
or of a glaucous or blue-green, one is not informed. Such a
description as Linnaeus gives of Rhus glabra might easily apply
to each one of five species, or of fifty, or of five hundred species
in a genus. It is therefore worthless for diagnostic purposes.
Coming down from the middle of the eighteenth century to
near the close of the nineteenth, we shall find that in American
books of American botany the Linnaean diagnosis of R. glabra
has met with a little amendment. That in Gray's Manual in
1890 reads thus : " Smooth, somewhat glaucous ; leaflets 11-31,
whitened beneath, lanceolate-oblong, pointed, serrate." The
expression, " whitened beneath," is one that helps us to fix on
certain shrubs, mostly southern, as representing this author's R.
glabra; but in New England there are at least two different
sumacs which this phrase completely excludes ; one of them,
inhabiting Massachusetts, shows not even a trace of bloom on
the lower face. Both of these, and with them several more
A STUDY OF RHUS GLABRA 1 73
species of the east and south, are excluded as having hardly
half of the " 11-31 " leaflets.
In Britton's Manual of 1901 is that of Gray somewhat ampli-
fied and therefore less safe. Here Gray's evasive term,
" pointed," gives place to the more definitive word " acumi-
nate," but this excludes yet another set of forms in which no
leaves are acuminate. Moreover, leaves and leaflets have dif-
ferent ways of being acuminate, in so much that, in order to be
able to really describe the apex of the leaflet in each segregate
of R. glabra, I find it necessary to use such truly definitive
terms as subulate-acuminate, cuspidate-acuminate, and such
phrases as slenderly acuminate and caudately acuminate. But
more unfortunate still is the Britton's Manual description of the
leaves as being dark-green above. That indeed applies to what
I take for real R. glabra, and to several of its Atlantic slope
allies but it holds good in not one of those far-southwestern;
species of New Mexico, Arizona and Utah, which said Manual
goes far out of its way to speak of as forming a part of R.
glabra. Even in the middle west and far-northwestern districts
not a tithe of the definable species can be said to have leaves of
other than a dull lightish green.
Finally, the authors of none of the books knew anything of
the differences of fertile inflorescences in this aggregate. That
these in the fruiting and mature state are narrowly oblong in
a few, oblong-fusiform in many, and almost or quite exactly
pyramidal in many more, a discovery the importance of which
will not be disputed, is a fact which is herein first brought to
notice.
It is my belief that even the flowers in some species will be
found to present characters available for the further establish-
ment of species here. Both calyx and corolla are far from
being the same in all ; but I have declined to make any use of
these for the reason that in the herbaria exist such multitudes of
specimens that are in flower only, and of which the fruiting
panicles are yet unknown.
In true Rhus glabra, and also in by far the greater propor-
tion of the segregates herein proposed, both branches and foliage
are wholly glabrous. In the diagnoses I permit this to be taken
.
1 74 GREENE
for granted, never mentioning such a matter except in the cases
of those two or three of the new species in which there occurs a
trace of pubescence.
Key to the Species.
* Leaves deep or dark green above (except in Xo. 9), usually
white with bloom beneath,
f Panicles of fruit oblong, or oblong-fusiform.
Leaflets very many, 17—21 or more, and large.
Leaflets oblong-lanceolate, obtuse at base and subsessile, at apex
abruptly pointed 1. R. glabra.
Leaflets oblong-lanceolate, sessile, slenderly long-pointed.
2. R. oreophila.
Leaflets linear-lanceolate, sessile and auricled at base, at apex
caudate-acuminate. 3. R. auriculata.
Leaflets less numerous, commonly 13-17.
Leaflets lance-oblong, tapering abruptlv at base and less abruptlv at
apex 4 . R. tthacensis.
Leaflets oval to oblong-lanceolate, merely acute at apex.
5. R. ashei.
tt Fruiting panicles broadest near the base and pyramidal.
Leaflets rather few (except in Nos. 6 and S).
Leaflets 17-21, sessile, oblong-lanceolate, acuminate.
6. R. pyramidata.
Leaflets very large, but only 13-17, subsessile, acute rather than
acuminate 7. R. caroliniana.
Leaflets 19-23, narrowly oblong-lanceolate, obtuse at base, the apex
subulate-linear S . R . atrovirens .
Leaflets 13-17 and small, oblong-lanceolate, coarsely serrate, slend-
erly acuminate 9. R. ptdchella.
Leaflets only 11-15, notably thin, attenuate-acute.
10. R. ladoviciaiia
Leaflets 11— 13, small but firm, subpetiolulate, abruptly but sharply
acuminate.. 11. R. arbuscula.
Leaflets 13-15, large, petiolulate, subfalcate, sharply acuminate.
12. R. petiolata.
Leaflets 13-17, oblong-lanceolate, subpetiolulate, triangular-subulate
at apex 13. R. valida.
Leaflets 13-15, sessile by a rounded base, the apex short, slenderly
attenuate 14. R. longula.
Leaflets only 11-13 and small, sessile, subulate-acuminate, their
rachis pubescent 1^. R. sandbergii.
..
A STUDY OF RHUS GLABRA 1 75
* * Leaves ample (except in No. 25), of a lighter green above,
less glaucous beneath. Panicles in almost all pyramidal.
All the species far western and northwestern.
Leaflets 13-17, subsessile, sparsely pilose, subulate-acuminate.
16. J\ . borealis.
Leaflets 1 1— 3.
1
Large, sessile, subfalcate-oblong, abruptly broad-pointed.
17. R. media
Oblong, subsessile, abruptly acuminate iS. R . cismontana.
Large, acutish at base and subpetiolulate, abruptly short-pointed.
19. R. sambucina.
Leaflets 13-17-
Shining above, sessile by an obtuse base, cuspidately acute.
20. R. miens.
Checkered light and dark green above, subsessile, cuspidatelv acu-
minate 21. R. tcsscllata
Leaflets 9-15, oblong-lanceolate, sessile, acuminate.
22. R. macrotkyrsa.
Leaflets 17-19, oblong-linear, sessile, acutish at base, long-acuminate.
23. R. arguta.
Leaflets 13-17, oblong, sessile, obtuse at base, the apex merely acute.
24. R. aprica.
Leaflets 11-13, narrowly lanceolate, sessile, acuminate.
25. R. occidentalis
* * * Leaves smaller, of fewer leaflets, altogether pale, very glau-
cous beneath. Panicles small, less definitely pyramidal.
All of arid southwestern regions (But Xo. 9. A'. pnl-
chclla, of the southern Appalachian mountains is naturally
of this group).
Leaflets 1 1-15.
Sessile, oblong-lanceolate, short-acuminate 26. R. albida.
Petiolulate, subfalcate-lanceolate, slenderly acuminate.
27. R. elegantida.
Leaflets 9—1 , sessile, oval to oblong-lanceolate 2S. R. sorbifolia.1
Leaflets 7-9, subsessile, lanceolate, slenderly acuminate deeply incise-
serfate 29. R. asplenifolia.
1. RHUS GLABRA Linnaeus.
Rhus rami's ex stipitc -pullulantibus giabn's, Banist. Catal. in
Ray, Hist. 2 : p. 1928. 1688.
Rhus Virginicum panicula sparsa, rami's patulis glahris,
Dillen., Hort. Elth. p. 323, t. 314. 1732.
:;
176 GREENE
Rhus glabra Linn. Sp. PL, p. 265. 1753, in part, excluding
both the shrub of C. Bauhin and that of Catesby.
Rhus glabrum, Mill. Diet. 1768?
Shrub commonly 2-3 m. high, with very few and stout diver-
gent branches: leaves mostly 5-7 dm. long, the rachis and
petiole very stout, the latter 1-1.5 dm. long; leaflets about
17-21, not crowded, very large, 8-13 cm. long, 3-3.5 cm. wide,
oblong-lanceolate, subsessile, abruptly and not slenderly acumi-
nate, evenly serrate, the serratures 12 or 13 on a side, texture
in maturity rather firm but not subcoriaceous, upper face deep
green and smooth, lower face glaucous but not excessively so
staminate panicle very large, often 3 dm. high, pyramidal,
almost 2 dm. wide at base in the largest, the pistillate, when in
flower nearly as long but fusiform, less than 1 dm. wide up and
down the middle part, in fruit oblong-fusiform, 6-10 cm. wide
below the middle ; drupelets very many, round-ovate.
This is the common and apparently the only glabrous Rhus
of the Potomac Valley in southern Maryland and eastern Vir-
ginia, ranging eastward and northward through southern
Pennsylvania, to Delaware, New Jersey, and to Connecticut, if
I refer here a flowering specimen in the National Herbarium
from Green's Farms, 1894, by C. L. Pollard. The type from
which the above description is drawn is the shrub as it grows in
the District of Columbia, and up and down the Potomac above
Georgetown.
The choice between this and the next for something to bear
the name R. glabra Linn, is made rather arbitrarily, perhaps
for either one may have been that grown in the Eltham garden
and figured by Dillenius. The two are distinct by their fruiting
panicles, and the fruit of the Dillenian type was unknown,
because only the staminate shrub was raised from the seed by
which it was introduced into Europe. As to the size of the
leaves and leaflets, however, the present species alone answers
to the account given by Dillenius ; hence the probability in favor
of this as identical with his.
Since Linnaeus himself did not describe the species ; and
since the one only synonym, quoted by him which carries with
it a description is that of Dillenius, the name R. glabra must be
A STUDY OF RHUS GLABRA 1 77
applied here unless it be left to fall into synonymy altogether.
Philip Miller, as a contemporary of Dillenius and Linnaeus,
and as a cultivator of these shrubs, might have been expected
to identify correctly the A', glabra of Linnaeus when he adopted
the name ; yet to what he so named in his Dictionary, the name
glabra does not really apply, for he describes its branches as
downy, thus awakening a doubt as to whether his R. glabra was
not some possible segregate of Rhus typJiina.
2. RHUS OREOPHILA, sp. nov.
Shrub 2-3 m. high : leaves 3-4 dm. long, the petiole 6-8 cm.
long : leaflets 19-27, closely approximate, not of the largest,
7—9 cm. long, 2.5 cm. wide, narrowly oblong-lanceolate, sessile,
rather slenderly acuminate, lightly and almost obsoletely ser-
rate, the serratures 10-12 on each side, texture firm, almost
subcoriaceous, lower face whitish with a dense bloom, upper
face by no means deep or dark green, of a rugulose-roughened
rather than smooth surface : fruiting panicle large and much
elongated, oblong-fusiform, 18-28 cm. long, only about 5 cm.
wide, very compact, the drupelets subglobose, nearly 5 mm. in
diameter.
Mountain districts of Maryland, Virginia, the Carolinas and
eastern Tennessee ; not in the lower hill country of the Potomac
Valley outside the mountains, nor at all northward. The type
specimen in the National Herbarium is on sheet No. 327800,
from Chapel Hill, North Carolina, by W. W. Ashe, no date of
collecting given, nor any specific locality. Two sheets from
the Biltmore Herbarium, the material gathered at different dates
in 1896 and 1897, without indication of either the collector or
special station, except the name Biltmore, represent the species
beautifully. So does another, from the mountains of Cocke
County, Tenn., by Mr. Thos. H. Kearney, September 14, 1897.
Yet another U. S. Herbarium specimen, in good foliage but
young fruit, is from near Luray, Va., by Mr. and Mrs. Steele,
August 30, 1 901.
The species is in contrast with R. glabra by smaller leaflets,
with denser bloom beneath, and a longer, narrower thyrsus of
larger and more closely compacted drupelets.
I78 GREENE
It may not perhaps be determinable to a certainty that the
preceding rather than this, was grown in London, and formed
the type of Dillenius' figure of leaves and staminate panicle.
But Banister's field, and probably that of Catesby also, by both
of whom seeds were sent to England, was the lower country,
where only what I have here called Rhus glabra is found.
3. RHUS AURICULATA, sp. nov.
More slender than R. glabra, all the parts somewhat smaller,
the fruiting panicles especially only about one-third as large :
leaves 2.5-3.5 dm. long; leaflets about 19, approximate, often
alternate, 7-10 cm. long, never more than 2 cm. in width, often
less, of linear-lanceolate outline, the apex caudately long-atten-
uate, the sessile base showing definite though small auricles,
the serratures light but rather close, 14-18 on a side, texture
subcoriaceous, the upper face light green, transversely rugose,
the somewhat sunken veins correspondingly prominent on the
very glaucous lower face ; fruiting panicles oblong or slightly
verging toward the pyramidal, 10-13 cm ' high 5 drupelets com-
paratively few, large.
A remote southwestern ally of R. glabra, with very definite
specific marks. It is known to me only as collected by Mr. C.
L. Pollard, August 11 to 12, 1896, the special locality, Agri-
cultural College, Oktibbeha County, Mississippi. The type
specimen occupies sheet 271931 of the National Herbarium.
There is a duplicate in Herbarium Field Museum which I have
seen. Mr. Pollard's distribution number 1261 is on these two
of his labels that I have seen.
The species must quite surpass R. glabra in beauty. Its
narrow slender-pointed leaflets seem to droop from the rachis
rather than to spread away from it horizontally. This, how-
ever, is characteristic of several other allies of R. glabra belong-
ing to regions lying westward.
4. RHUS ITHACENSIS, sp. nov.
All the parts smaller and more slender than in R. glabra, the
branches not glaucous, seldom glaucescent : leaflets 13-17,
A STUDY OF RHUS GLABRA 1 79
sessile by an abruptly acutisb base, 6-7 cm. long, saliently
serrate, tbe serratures 13-15 on a side, upper face dull deep
green, lower glaucous but less so than in R. glabra, the texture
thinner: fruiting panicle small comparatively, long-peduncled,
12-18 cm. long, oblong fusiform, not very compact, its branches
thinly tomentellous ; drupelets below medium size, notably
smaller than in R. glabra.
Seems to take the place of R. glabra everywhere to the west-
ward of the Alleghenies in western Pennsylvania and New
York, and in northern Ohio. The station for the type is near
Ithaca, New York, as the name might indicate ; the type speci-
men is on sheet No. 225037 U. S. National Herbarium ; was
collected at Fall Creek, September, 1893, by K. M. Wiegand.
Sheet 292227 is the same from Westmoreland County, Penn-
sylvania, 1878, by P. E. Pierron, consisting of uppermost leaves
and a panicle each of staminate and pistillate flowers. It is
also in U. S. Herbarium in flower only, from Elyria, Lorain
County, northern Ohio, as collected in flower only by A. E.
Ricksecker, August 1, 1894.
Excellent specimens, true to the type, are in the Herbarium
of the Geological Survey of Canada as follows : sheet 34165
from Sandwich, Ontario, by John Macoun, July, 1901 ; also
another from Bellville, Ontario, by the same as early as 1867,
this in male flower only.
All the so-called Rhus glabra from the geographic region so
indicated, differs from the southern R. glabra and the New
England R. -pyramidata in points quite sufficient to establish it
in the rank of at least a strong subspecies.
5. RHUS ASHEI (Small).
Rhus Caroliniana Ashe, Bot. Gaz. 20: 548, 1895, not of Mil-
ler, Diet. 1768.
Schmaltzia Ashei Small, Fl. 729.
Shrub erect but low, only 3-5 dm. high ; leaflets 13-17, oval
to oblong lanceolate, 5-7 cm. long, acute, not acuminate, sessile,
rather coarsely subserrate-dentate, the teeth about 10 on each
side, pale beneath but not glaucous : panicle of ovoid outline,
large for the plant, 10-15 cm - l° n g-
;
I SO GREENE
In old fields and low woods of middle North Carolina, col-
lected by Ashe, who correctly indicated it as a good new species
but under a name long preoccupied.
6. RHUS PYRAMIDATA, sp. nov.
Both the shrub and its foliage smaller than in R. glabra, the
mature leaves firmer, almost subcoriaceous, equally white with
bloom beneath, the whole leaf 3 dm. long or less; leaflets 17-
21, sessile, oblong-lanceolate, acuminate, lightly serrate, the
serratures 12-16 on each side: fruiting panicle large, notably
compound, the primary branches being again widely branched,
the whole subpyramidal, 8-12 cm. wide toward the base and
only 12-18 cm. high ; drupelets very numerous, smaller than in
southern allies, 3 mm. wide, suborbicular inclining to ovate.
This definition I trust may prove to include a large part of
what has been called Rhus glabra in northern New York, New
England and adjacent Canada. That which I wish to cite as
the type specimen is on sheet 312308 of the National Her-
barium, and was collected near Lake Waccabuc, Westchester
County, New York, by Mr. C. L. Pollard, August 12, 1894.
The locality lies easily within the range of Colden's field studies
made in the middle of the eighteenth century or earlier. It
might therefore be guessed that R. -pyramidata also entered into,
and formed a part, bibliographically speaking, of Linnaeus'
aggregate R. glabra. But this cannot be established as a fact
nor would it alter the situation in the least if it could be ; for
Colden did not describe the shrub, and his work is of later date
than that of Dillenius, to which we are obliged to resort for any
described and definable thing that may bear the appellation
Rims glabra Linn.
The Rhus glabrum of Philip Miller, which he said was from
New England, and which he reported as cultivated in his time
under the name of New England Sumach, cannot have been the
present species ; for he attributes to that " downy " branches, as
I have already remarked under R. glabra.
There is presumptive evidence in the herbaria of the existence
in southern New England of at least two more species, the diag-
noses of which cannot be safely made for want of fruiting pani-
1
A STUDY OF RHUS GLABRA 1 8
cles. One of these I have seen only in the herbarium of the Field
Museum, sheets 13682 and 185 10. Both specimens were col-
lected and distributed by the late D. C. Eaton, somewhere near
New Haven; no date. Another is from South Hadley, Mass.,
1887 ; the collector's name illegible. This is on sheet 275445
of U. S. National Herbarium. By evident marks of foliage
and detached flowering panicle this is certainly distinct from all
others known, and nearest R. ithacensis, unless the panicle be
pyramidal.
7. RHUS CAROLINIANA Miller.
RJius glabra, -panicula sfiarsa coccinea, Catesby, Carol. App.
4, t. 4.
Rhus glabra Linn. Sp. PI. 2 ed. 380 (1762) in part onlv, and
as to the shrub of Catesby.
Rhus Caroliniana Mill. Diet. ed. 1768.
Rhus elegans Ait. Hort. Kew. 1 : 365. 1789.
Shrub 2-3 m. high: leaves large, but of only 13-17 leaflets,
these not closely approximate but large, commonly 8-1 1 cm.
long, 2-3 cm. wide, subsessile, acute rather than acuminate,
strongly serrate, the serratures about 9 on a side, upper face
deep green, lower glaucous : fruiting panicle large and not com-
pact, exactly pyramidal, 2 dm. long or more, 1.5 dm. wide at
base ; drupelets uncommonly small, bright scarlet rather than
dark-red in maturity.
A South Carolinian species, collected, described and illustrated
by a large folio plate, in the middle of the eighteenth century,
by Catesby, who also was the medium of its introduction into
English parks and gardens at the same time; from which, also,
it is probably long since lost. That it is thoroughly distinct from
R. glabra Catesby's description and figure demonstrate, to all
who know Rhus glabra. Philip Miller also knew it to be distinct,
and in the year 1768 gave it the trivial name of R. caroliniana.
Again, as still grown in Kew Gardens twenty years later than
the date of Miller's work, Aiton, as if ignorant of Miller's
name R. caroliniana, published it again as distinct from R.
glabra under a new name, R. elegans.
From a highly instructive paper on some small trees observed
152 GREENE
in Georgia, published by Mr. Roland M. Harper last year, 1 it
appears to me probable that this zealous explorer of southern
fields and woods has, without knowing it, rediscovered this
large scarlet-fruited Rhus of Catesby. Mr. Harper says that
he found what he took for Rhus]glabra "in a cane-brake on
the bank of the Coosa River, in Floyd County, about twelve
miles below Rome, Georgia, a veritable little grove of this
species, in which many of the specimens were as much as seven
inches in diameter and thirty feet tall, with the lowest branches
higher up than I could reach." Mr. Harper describes the
drupelets of this tree as " bright scarlet," just the color men-
tioned by Catesby more than a century ago, as being one among
several marks by which R. caroliniana was to be distinguished
readily from the then well known R. glabra, the fruits of which
are unvaryingly of a dark crimson when mature.
8. RHUS ATROVIRENS, sp. nov.
Stout upright shrub, the young branches and lower face of
foliage not very glaucous : leaves about 3 dm. long, with
unusually stout petiole and rachis, the whole more firm and
ascending than in allied species : leaflets about 23 and closely
approximate, subcoriaceous, of a dark green above, pale but
not white beneath, of only middle size, 5-7.5 cm. long, nar-
rowly oblong-lanceolate, subsessile by an obtuse base, the apex
subulate-linear, entire, the serratures of the margin, though
obscure very numerous, 16-22 on each side : panicle of fruit
narrowly pyramidal, 1.5 dm. long, compact; drupelets larger,
than in the last, quite rotund, 4 mm. wide, deep crimson as in
most species.
Mountain region of northern Alabama ; type in the National
Museum No. 19814, from near Gadsden, 1888, by Gerald Mc-
Carthy. Distinguished from one and all the foregoing by its
narrow and crowded dark green and rather rigid leaflets.
9. RHUS PULCHELLA, sp. nov.
Branches not stout, angular, glaucous, minutely lenticellate :
leaves not large, about 2 dm. long, rather long-petioled, of a
1 Torreya, 5 : 163.
;
A STUDY OF RHUS GLABRA 1 83
somewhat glaucescent green above, very glaucous beneath
leaflets 13-17, small, sessile, drooping on the rachis rather than
spreading away from it on the same plane, oblong-lanceolate,
5-6 cm. long, slenderly acuminate and somewhat irregularly
and coarsely serrate-toothed below the acumination, as well as
more lightly and evenly serrate in the middle : panicle pyram-
idal, small, about 8 cm. long, slender-peduncled, somewhat
recurved or drooping.
Known only from Yellow River, near McGuire's Mill,
Guinnett County, Georgia, July 11, 1893, John K. Small;
type in National Museum, sheet No. 19816. A small and
very graceful species, recalling some of the far-southwestern
forms found in Arizona.
10. RHUS LUDOVICIANA, sp. nov.
Shrub with quite slender branches, the foliage not large
ascending, glabrous except as to the hairy line of the rachis,
about 2.5 dm. long; leaflets 11-15, opposite, of thin texture
even in full maturity, dull green above, moderately glaucous
beneath, 5-8 cm. long, attenuate, acute rather than acuminate,
evenly serrate, the serratures 12-16 on each margin: panicle
small, pyramidal, 8 cm. long, 4 cm. broad toward the base ;
drupelets obliquely orbicular, of a dark red-purple and not
strongly pubescent.
The type specimen is in my own herbarium, from along the
seaboard in southwestern Louisiana, at Cotes Blanches, October
10, 1884, by A. B. Langlois. A strongly-marked, probably
small species, said to form low thickets in a peculiar maritime
region that is still almost unknown botanically.
If the Rhus angustifolia Bauhin, believed to have come from
the coast of Brazil, was derived from some North American
coast by that voyager of nearly or quite three centuries ago, it
would be easy to fancy that the specimen in Burser's herba-
rium, which became Bauhin's type, was from some shore of the
Gulf of Mexico, and even may have been identical with what is
here described as R. ludoviciana, and which is the only known
maritime ally of R. glabra. And that which may elevate this
Proc. Wash. Acad. Sci., February, 1907.
184 GREENE
fancy almost or quite to the rank of a probability is the at least
highly interesting coincidence that my type specimens of R.
ludoviciana bear the only leaves and leaflets known to me that
answer to Bauhin's description of those of Burser's specimen.
He gave the number of the leaflets, their form and dimensions,
the serrated character of their margin, and the narrowly atten-
uate apex, not omitting mention of the darker green upper and
paler lower faces of the leaflets.
This, as I have said before under R. glabra, is the earliest
element, historically speaking, that enters into Linnaeus' aggre-
gate ; and had the latter described his Rhus species as carefully
as Bauhin had described his a hundred and thirty years before
him, the task of the twentieth century botanist at this juncture
would have been much less difficult.
11. RHUS ARBUSCULA, sp. nov.
Shrub low, tree-like in form though commonly less than 1 m.
high : branches of the season glabrous, glaucous, obscurely
angled, not very stout, but foliage large and ample ; largest
leaves 3 dm. long, of 11 to 13 rather remote leaflets, these
lance-oblong, 7 to 9 cm. long, often subfalcate, notably inequi-
lateral at base, never quite sessile, the petiolule definite though
very short, upper face of leaflets light or deep-green, the lower
very glaucous ; serratures moderately salient, 10 to 15 on each
margin, the apex abruptly and sharply acuminate : panicle
pyramidal, very small for the foliage, usually but 7 to 9 cm.
long ; drupelets of the smallest.
Near Culver, Marshall County, Indiana ; collected August 18,
1906, by Mr. H. Walton Clark, of the United States Bureau of
Fisheries.
The type locality, and thus far the only known station, is a
barren hill above the eastern shore of Lost Lake, near Culver,
Indiana. The specimens at hand are two, both of them excel-
lent, but evidently not from the same bush, and, as I suspect,
from somewhat different exposures. One of them has a maturer
foliage beginning to redden for the autumn ; and the branch,
as well as the rachis of the leaves in this all show much bloom.
A STUDY OF RHUS GLABRA 1 85
This I designate as the type specimen. The other differs only
in having foliage of a clear and vivid green, and the stem shows
but little bloom. Both specimens have been presented to, and
will be preserved in, the U. S. National Herbarium.
12. RHUS PETIOLATA, sp. nov.
Branches not stout, glabrous, glaucous, striate, roughened
also by small and very protuberant lenticels : leaves ample, not
long, though long-petioled : leaflets about 13, large, 8-10 cm.
long, oblong-lanceolate and often subfalcate, distinctly petiolu-
late, the base obviously inequilateral, apex sharply acuminate,
the sides sharply but unevenly serrate, the serratures 13 to 15,
upper face of leaflets of a rich deep green, the lower very
glaucous : panicle small for the foliage, pyramidal, 10 cm. high,
compact, the branches thinly and rather stiffly hirtellous ; drupe-
lets rather large.
Prairie region of the interior of Minnesota, the type from
near Spicer, Minn., August, 1892, W. D. Frost, Herb. Field
Mus. sheet No. 140259. Well marked by the large definitely
petiolulate leaflets.
13. RHUS VALIDA, sp. nov.
Branches very stout and robust, upright, at the end of the
first season no longer glaucous but light brown, between cin-
namon and chestnut-color, striate, copiously lenticellate : leaves
not large in proportion, less than 3 dm. long ; leaflets about 15,
approximate, short-petiolulate, oblong-lanceolate, 6-10 cm.
long, with about 11 serratures on each margin and a short tri-
angular-subulate point, texture subcoriaceous, upper face dull
deep green and transverse-rugose, lower fairly glaucous but
not white: panicle rather oblong-pyramidal, large, 12-14 cm *
high, its branches thinly tomentulose-pubescent : drupelets
many, large, little compressed, rather thinly plushy.
Even in the herbarium specimens this impresses one as some-
thing wholly apart from any and all eastern and southern
shrubs that have been called R. glabra. The very stout stri-
ated, lenticellate and upright branches, with smallish foliage
1 86 GREENE
evidently more ascending than is usual in the genus, and the
large rather narrow panicle — all these marks indicate a
species, and one possibly somewhat local about Lake Michigan.
The type specimens, all in Herbarium Field Museum, are from
Hinsdale, a suburb of Chicago, and were collected October 12,
1902, by Ernest C. Smith, his distribution No. 577. I also
refer here without hesitation Mr. O. E. Lansing's No. nil, as
in Herbarium Field Museum, from West Pullman, 111., Septem-
ber 8, 1900.
Later than all these are specimens sent me late in August,
1906, from near Nashotah, Wisconsin, by Dr. H. V. Ogden
of Milwaukee. These came to hand after the above diag-
nosis of J?, valida had been finished, and the type specimens
returned to the Field Museum. But they answer perfectly to
my description of the species in every particular, and therefore
only further confirm it while extending its range.
14. RHUS LONGULA, sp. nov.
Stem and branches not known : leaves about 3 dm. long, with
long stout ascending petiole, and 13 or 15 approximate leaflets,
these 7-9 cm. long, sessile by a rounded base, the apical acumi-
nation short though slenderly attenuate, the margins lightly and
almost subcrenately serrate with about n or 12 serratures, tex-
ture firm, hardly subcoriaceous, color dark dull-green above,
whitish-glaucous beneath : fruiting panicle narrowly oblong and
greatly elongated, 18 cm. long, hardly 5 cm. wide at the widest
part, the short branches hirtellous-tomentulose ; drupelets of
middle size and numerous.
Bluffs of the Mississippi River far northward ; the special
station for the type somewhere near Stockton, Minnesota ; the
type specimen in U. S. Herbarium, No. 19813, collected by
Mr. John M. Holzinger, August 23, 1888. Also on sheet
19811 is aflowering specimen by the same collector, of "May,
1889," which appears to be the same specifically. The station
for this is not named.
That R. longula, away at the western North should flower
in May is noteworthy for its ally, R. glabra, so far southward;
as the valley of the Potomac does not begin to flower until July.
A STUDY OF RHUS GLABRA 1 87
The eastern analogue, R. ithaccnsis, in Pennsylvania, does
not come into flower before the end of July or early August.
These segregates of R. glabra from the northwest, by their
almost vernal flowering, reassert for themselves a more distant
relationship to the eastern types than that which we should infer
from their visible characters alone.
15. RHUS SANDBERGII, sp. nov.
Rhus glabra var. sandbergii, Vasey & Holzinger in Herbarium
Field Museum.
Very dwarf, flowering and fruiting freely at 1.5-2 dm. high ;
branches of the season 4-5 cm. long, angular, rusty-tomentulose
and with also a few hirsute hairs, older branches glabrate :
leaves small, barely 1.5 dm. long, the slender rachis pubescent
on all sides; leaflets 11-13, sessile, oblong-lanceolate, 4-6 cm.
long, appressed-serrate, the serratures 15-17 on each margin,
apex subulate-acuminate, both faces nearly or quite glabrous,
the upper deep green, the lower glaucous : panicle very small,
seldom exceeding 5 cm. long, subpyramidal, its branches
densely and subtomentosely hirsute : drupelets of the ordinary
size and color.
Said to grow in crevices of rocks, near the head of Lake
Superior at Thompson, Minnesota, where it was collected in
flower in July, and in fruit in August, 1891, by J. H. Sandberg,
who afterwards distributed it under numbers 401 and 921. His
locality for it is the only one known. I would indicate as the
type specimen the fruiting one on sheet 19898 of the National
Herbarium. Happily Mr. Sandberg, unlike most collectors of
Rhus specimens, gathered this in both flower and fruit.
Prof. John M. Holzinger of the Normal School at Winona,
Minnesota, would have proposed this species as new, in his
paper published in the Minnesota Botanical Studies, part 8, in
1896, but was deterred by the opinion of some authority who
would have reduced R. typhina and R. glabra to one species,
with this as a connecting link between them.
I 88 GREENE
16. RHUS BOREALIS, sp. nov.
Shrub evidently large but not stout, at least as to the branches,
these smooth, glabrous, glaucous : leaves ample as to breadth,
but not greatly elongated, 3 dm. long, the usual hairy line of
the rachis quite hirsute, but other parts of the rachis, and also
the midvein of the leaflets on both faces showing a few pilose
hairs ; leaflets 13-17, subsessile, broad and approximate, oblong-
lanceolate, 8-1 1 cm. long, subulate-acuminate, coarsely and
closely subcrenate-serrate, the serratures about 14 on a side,
texture of leaflet uncommonly thin, upper face of a light but
rather lurid green, the lower glaucous almost to whiteness :
panicle not large, 11 cm. long in fruit, narrow-pyramidal, dis-
tinctly pedunculate, the peduncle and branches of panicle hir-
sute, the hairiness more or less distinctly retrorse : drupelets
larger than the average and of a lighter color, being bright
crimson.
Central Michigan near Alma, on dry ridges, collected Au-
gust 12, 1895, by Charles A. Davis, the type specimen in the
Herbarium of the Field Museum, Chicago. A fine species,
perhaps common enough in central Michigan, and probably
beyond the boundaries of the State southward, a region in which
little or no effective collecting has been done in late years. But
there is a poor flowering specimen, or fragment, in the National
Herbarium which, by the one leaf it bears, I can refer here. This
appears to have been sent by Mr. Beale, in 1899 ; but there is
nothing to indicate who collected it, or where. Although pubes-
cent, this bears no relation to R. hirta.
17. RHUS MEDIA, sp. nov.
Branches rather sharply angular in maturity and sparsely
dotted with small lenticels : leaves large but not elongated, only
2 dm. long, rachis not stout, whitish with bloom, glabrous except
as to a tomentulose line ; leaflets about 13, large, sessile, oblong
or subfalcate-oblong, broadly and abruptly pointed rather than
acuminate, appressed-serrate, the serratures 13-15 on a side,
the whole leaflet of firm texture and about 8 cm. long, 2-2.5
cm. wide, of a dull lightish green above, quite glaucous beneath :
A STUDY OF RHUS GLABRA 1 89
fruiting panicle rather lax, slender-peduncled and as if some-
what drooping but of pyramidal outline, its branches rather
finely pubescent ; drupelets of middle size, notably oblique,
acutish.
Inhabits the region of scattered woodlands and small prairies
in southern Michigan and northern Indiana and Illinois, if I
rightly refer to it rather numerous specimens, collected in various
places, all in young leaf and flower only. Such are in the her-
bariafrom Warrenville, 111., by L. M. Umbach, July 2, 1895, and
by Charles C. Deam at Bluffton, Indiana, 1897 ; but the type
sheet, No. 1 24146 of the Field Museum, a perfect fruiting speci-
men, is from Jackson County, Michigan, by S. H. and D. R.
Camp, September 19, 1898. Sheet 6072 of the same herbarium,
from Stark County, Illinois, may or may not be the same. Its
detached fruiting panicle may well belong here, but the one
leaf shown is attached to a flowering branch, and therefore im-
mature.
18. RHUS CISMONTANA, sp. nov.
Shrub doubtless low, all its parts reduced in size and rather
slender as to branches and leaf-rachis, all these pale and
glaucous: leaves 1.5-2 dm. long, ascending; leaflets 11-13,
not crowded, of a pallid green above but only glaucescent
beneath, mostly oblong and abruptly acuminate, 4-6 cm. long,
only subsessile, or some of the more basal leaflets definitely
petiolulate, sharply and rather closely serrate, the serratures
10-12 on each side, even the most mature state of foliage not
subcoriaceous, though firm : fruiting panicle about 9 cm. high,
pyramidal but narrowly so and compact ; outline of drupelets
slightly inclining to ovate, being a trifle longer than broad, not
depressed but rather acutish at summit.
Open hills of the more westerly parts of Nebraska and Kansas,
as well as probably in adjacent Colorado, if not Wyoming. The
type specimens are in U. S. Herbarium No. 210241, collected
by Mr. Rydberg in Thomas County, Nebraska, 1883 ; and Mr.
J. B. Norton's so-called R. glabra from Riley County, Kansas,
collected in 1895, appears to be quite the same; probably even
Mr. Clements' specimens from northeastern Nebraska, 1893,
I9O GREENE
belong here, for, while in these the foliage is larger, the leaflets
seem to have all the marks of R. cismontana, even to the peti-
olules, these being very evident.
19. RHUS SAMBUCINA, sp. nov.
Stem and branches unknown : leaves of few leaflets, the
whole leaf, including the rather long petiole, little more than 2
dm. long, the leaflets 11 or 13, approximate, large, 7-10 cm.
long, oblong-lanceolate, acutish at base and subpetiolulate, the
apical acumination rather abrupt and short, the sides with 11 or
12 quite large and sharp serratures, the texture of mature foliage
not known, color of upper face a pale glaucescent green, of the
lower only paler, with nothing of the white bloom of real R.
glabra: panicle not pyramidal even in flower, but rather oval,
or at most oval-subpyramidal, in fruit oval, decidedly lax, the
branches villous-pubescent ; drupelets of middle size.
Singular species, with broad short leaves made up of few and
much serrated leaflets, all pale green on both faces. The locality
of this is remote and but little known. The type specimens
are in Herbarium Field Museum, sheet 140404, and are from
near Piedmont, South Dakota, by Alice Pratt, June and August,
1895. Unfortunately only the young foliage is present; the
one fruiting panicle was preserved only as detached from the
branch ; yet this matches perfectly, in its peculiar branching
and laxity, the flowering panicles.
In the same herbarium, sheet 123606, are flowering speci-
mens of what seems to be the same, from southern Iowa,
Decatur County, T. J. Fitzpatrick, June 13, 1896.
20. RHUS NITENS, sp. nov.
Shrub stoutish, perhaps low, young branches and also petioles
and lower face of foliage merely glaucescent : leaves short and
short-petioled, the whole leaf barely 2 dm. long, the petiole and
rachis stout, ascending; leaflets 13-17, closely approximate,
seldom opposite, lance-oblong, 4.5-6.5 cm. long, subcoriaceous,
sessile by an obtuse base, the apex cuspidately acute rather than
acuminate, evenly but not deeply serrate, the serratures 10-12
:
A STUDY OF RHUS GLABRA I9I
on a side, upper face of a lightish green but somewhat polished,
the lower only pale, not whitened : fruiting panicle small, only
about 8 cm. high, definitely pyramidal, its branches short,
sparsely hirtellous : drupelets immature but perhaps full grown,
orbicular, or a little broader than high.
At 6000 feet in the mountains near Provo, Utah, July 10,
1894, as collected by Mr. Marcus E. Jones, his No. 5612 as in
the National Herbarium. This differs from all other far-western
species in that its foliage is almost as highly polished as that of
R. copallina.
21. RHUS TESSELLATA, sp. nov.
Shrub low, copiously and densely leafy, the leaves rigidly
ascending, about 2.5 dm. long, the pinnae approximate; leaflets
about 15, lance-oblong, 5-7 cm. long, not quite sessile, cuspi-
dately acuminate, evenly and quite sharply serrate, the serra-
tures 13-17 on a side, the texture subcoriaceous even at flowering
time, upper face very smooth and somewhat shining, in general
dark green, showing very prominently the fine whitish midvein
and veinlets, but some intervals between veinlets wholly of a
light green, exhibiting the whole surface as notably checkered,
lower face merely pale and glaucescent, not glaucous : panicle
small for the foliage ; fruit not seen.
Foothills of the Rocky Mountains in northern Colorado, at alti-
tudes of 6000 to 7000 feet; type specimen in U. S. Herbarium
No. 257466, collected by J. H. Cowen, July 20, 1895 ; no spe-
cial locality mentioned. The species by leaf characters alone
is a very good one, even if the checkering of dark and light
green be but accidental or occasional. The species here defined
may or may not include all the so-called R. glabra of eastern
Colorado mountains.
22. RHUS MACROTHYRSA Goodding.
Rhus macrothyrsa Good. Bot. Gaz. 37 : 56. 1904.
Shrub 1.5-2.5 m. high, glabrous except as to vigorous young
growing shoots, these at base ferruginous-tomentose : leaves
2-2.5 dm. long; leaflets 9-15, green above, not glaucous be-
neath, oblong-lanceolate, sessile, acuminate, sharply serrate
;
I92 GREENE
fruiting panicle open, large, oblong-fusiform, 15-25 cm. long,
recurved, its branches coarsely pubescent : drupelets little com-
pressed, 3 mm. wide.
Calientes, Nevada, 1902, L. N. Goodding. No specimens
seen by the writer, but by the description the species must be
distinct enough, and probably local in southern Nevada.
23. RHUS ARGUTA, sp. nov.
Shrub said to be 1-3 m. high, the branches stoutish, smooth,
glabrous, glaucous even in full maturity ; leaves notably ascend-
ing rather than spreading, 3 dm. long, the petiole uncommonly
elongated and, like the rachis, very glaucous; leaflets 17 or 19,
narrowly oblong-linear or subfalcate, 6-8 cm. long, sessile by
an acutish base, closely, sharply and saliently serrate, the ser-
ratures 15 or 16 on a side, the acumination long and narrow,
upper face deep green but dull, the transverse veins conspicu-
ously paler, lower face very glaucous : panicle not large, 10-12
cm. high, pyramidal, its branches hirsutulous ; drupelets of the
largest.
Species of the Pacific slope, apparently common in the
Columbia River region, at least eastward ; very possibly an
aggregate, resolvable into several ; but the type of the above
diagnosis is from Rhea Creek, Morrow County, Oregon, and
was collected by J. B. Leiberg, September 11, 1894, his No.
893 as in U. S. Herbarium. The following, all from western
Washington, are more or less true to this type : sheet 93075 in
Herbarium Field Museum, from near Spokane, in flower only
sheet 93076 of the same, from the same region with lax pyram-
idal panicle very much larger, leaflets larger, greener on both
faces and by no means sharply serrate ; A. D. E. Elmer,
Wawawai, 1897 ; Frank Kreager, Spokane County, 1902 ;
Sandberg & Leiberg, Rock Island, 1893, and Robert Horner,
Waitsburg, 1897, these last all as in U. S. Herbarium, likewise
from Idaho, A. A. Heller, Nez Perces County, 1896, his No.
3421. This is quite true to the type as to foliage, but in flower
only; a fruiting specimen, from Salmon River, Vernon Bailey,
1895, with leaflets not so typical.
A STUDY OF RHUS GLABRA 193
Among all these there is nothing of Torrey's Rhus glabra^
var. occidentals. Nearly all that I have seen of Pacific coast
material which matches that of the Wilkes Expedition, comes
not from Oregon or Washington, but from British Columbia.
24. RHUS APRICA, sp. nov.
Dimensions of shrub, and characters of branches unknown :
leaves as a whole remarkably broad and short, the leaflets being
few and approximate but large, subcoriaceous, deep green
above, light green beneath, but without bloom ; leaflets about
15, oblong, 6-8 cm. long, obtuse at base and sessile, at apex
only cuspidately acute, not acuminate, very evenly and quite
distinctly though not sharply serrate, the serratures 10 or n on
each margin : panicle pyramidal, small, about 8 cm. high, its
branches only sparingly and obscurely villous-pubescent ; drupe-
lets rather large.
Very well marked by its few and large leaflets green on both
faces; but known only as collected by M. W. Gorman, on
Camas Creek in the Washington State Forest Reserve, August
20, 1897. It is said to occupy dry open grassy slopes. The
type specimen is in U. S. Herbarium. Its label bears Mr.
Gorman's collection number 632.
25. RHUS OCCIDENTALIS (Torrey).
Rhus glabra occidentalis Torr. in Bot. Wilkes' Exp. 257.
1874.
Only flowers and young foliage known : leaflets (in what
should be the type specimen, U. S. Herbarium sheet No. 19819)
11-13, oblong-lanceolate, sessile, notably acuminate, beneath
only glaucescent ; the panicle small and very slender peduncled ;
even the branch slender, but quite glaucous.
The label bears, in the handwriting of Asa Gray, the legend,
"Okanogan, Wash. Territory."
The Okanogan region lies partly in Washington and partly in
British Columbia, and all the more recent specimens seen by the
writer which match the type are from the Canadian part of the
region. Sheet 4471 of the Canadian Survey Herbarium, Arrow
194 GREENE
Head Lake, near Lake Okanogan, is every way true to the
type, except that the leaflets are less numerous ; nine in most of
the leaves and none with a greater number, a few having seven
only. In the same herbarium 4473, from Spence's Bridge, in
the same general region, has mostly 13 leaflets. The like is
true in the case of number 63749, collected at Cascade, B. C,
by Mr. J. M. Macoun in 1902. But all these specimens are in
one and the same unsatisfactory condition of early flowering,
with foliage, of course, not fully grown. They indicate, how-
ever, a northerly species, from which the two Washington spe-
cies herein characterized are sufficiently distinct. Not, however,
until mature foliage and fruiting panicles of it shall be brought
to light can R. occidentalis be properly described.
26. RHUS ALBIDA, sp. nov.
Probably low, the branches not robust, very light-colored
and, with the rachis and lower face of leaves, much whitened
with bloom, even the upper face of foliage of a pale color and
glaucescent : leaves 1.5-2.5 dm. long; leaflets about 13, not
crowded, not deflected but spreading, subsessile, 4-6 cm. long,
oval to oblong-lanceolate, abruptly acute or short-acuminate,
saliently serrate, the serratures 10-14 on each side : fruiting
panicle about 1 dm. high and quite broadly pyramidal, its
branches only very delicately but rather densely velvety : drupe-
lets much compressed and acutish.
As far as known this very beautiful Rhus is local on the San
Francisco Mountain not far from Flagstaff in northern Arizona.
The type specimen, sheet No. 410696 of the National Her-
barium, was collected there, at an altitude of between 6000 and
7000 feet, August 18, 1901, by J. B. Leiberg, his distribution
No. 587 1. A perfect male flowering specimen is in my own
herbarium, as collected by myself at the same station, July 13,
1889. Again, National Herbarium sheet 334404 holds a flower-
ing branch from the same locality by D. T. MacDougal, his dis-
tribution No. 309, July 18, 1898. This, too, from an altitude
of about 7000 feet. The late date of its flowering, as an ally
of Rhus glabra in the generally torrid climate of Arizona, indi-
cates the subalpine character of its habitat.
A STUDY OF RHUS GLABRA 1 95
27. RHUS ELEGANTULA, sp. nov.
Branches slender, glabrous, of a distinctly pinkish brown
underneath a coat of bloom: leaves small, 1.2- 1.8 dm. long,
the slender rachis quite white with bloom, its villous line very
marked; leaflets 11-15, loosely arranged, spreading or slightly
deflected, distinctly petiolulate, 4-6 cm. long, narrowly subfal-
cate-lanceolate, at least the long and slender acumination falcate,
sometimes the whole leaflet, the serratures, about 8 on a side,
more or less sharply prominent, the texture rather firm, color of
upper face pale bluish-green, the lower whitish with bloom :
fruiting panicle large in proportion to the foliage, commonly
more than 1 dm. high, pyramidal but narrowly so, its branches
thinly villous with ascending or spreading hairs : drupelets
small, arranged upon simple racemose branches of the panicle,
compressed, acutish.
Mountains of extreme southern Arizona along the Mexican
boundary, the typical specimens from about Fort Apache, by
Edward Palmer, June, 1890 ; these on sheet 19808 of the
National Herbarium ; others distributed by Dr. Palmer under
his No. 585. Probably the same as a specimen from the Santa
Catalina Mountains, September, 1896 by J. W. Tourney, U. S.
Herbarium sheet 441724. Lastly rather larger specimens, but
otherwise true to the character, have come in this season from
the Huachuca Mountains, sent by Mr. J. C. Blumer, who col-
lected them late in August, 1906.
28. RHUS SORBIFOLIA, sp nov.
Shrub apparently low and not stout, the young branches and
lower face of foliage not whitened, hardly paler than glauces-
cent : leaves small, only 1-2 dm. long, spreading away from
the stem divaricately, or even a trifle deflected, the petiole and
rachis rather slender; leaflets few, only 9 or 11 and loosely
arranged, dull deep green above, glaucescent beneath, of small
size, 2.5-6 cm. long, oval to oblong-lanceolate, sessile by an
abruptly acutish base, at apex subulate pointed rather than
acuminate, rather remotely and sharply serrate, the serratures
only 7-9 on each margin : panicle of staminate flowers pyram-
I96 GREENE
idal, 12 cm. long : sepals triangular, acute; petals twice as
long, oblong, obtuse, the anthers equaling them.
Type from mountains west of Las Vegas, New Mexico, G.
R. Vasey, 1881 ; U. S. Herbarium No. 195 10. Species with
most characteristic habit and foliage.
29. RHUS ASPLENIFOLIA, sp. nov.
Shrub evidently dwarf or at least low, the leafy branches
short, slender, tortuous, glabrous, glaucous : leaves small,
about 1.5 dm. long, the rachis slender, deeply and narrowly
furrowed and the hairy line obvious ; leaflets only 7-9, pale
green above, moderately glaucous beneath, oblong-lanceolate to
lanceolate, 3.5-5.5 cm. long; subsessile, acuminate, very irreg-
ularly and somewhat incisely serrate, even coarsely so, the
serratures now and then so deep and large as to amount to lobes
rather than serratures : only a staminate panicle seen, this
narrowly pyramidal, 5 cm. long.
Type from Wolf Creek, Wyoming, July 12, 1896, A. Nelson,
distributed to U. S. Herbarium, under No. 2303, mounted on
U. S. Herbarium sheet 285144. Manifestly intermediate be-
tween the Nebraskan R. cismontana and the characteristic
species of Arizona ; the foliage peculiar.