GRIFFITHS-—THE GRAMA GRASSES, 857 
HERBARIUM SPECIMENS. 
Mexico: Nelson 2940, Chiapas. 
GuaTteMALA; Heyde & Lux 423, Santa Rosa. 
2. Pentarrhaphis polymorpha (Fourn.). 
Atheropogon polymorphus Fourn. Mex. Pl. 2: 141. 1881. A few spikes of the 
type before me identify this plant perfectly. Fournier had smaller plants, however, 
than any in the U.S. National Herbarium, as indicated by a photograph of the speci- 
mens in the herbarium of the Muséum at Paris. 
Bouteloua fourneriana Vasey; Wats. Proc. Amer. Acad, 22: 461. 1887. A name 
only. 
Pentarrhaphis fourneriana Hack. & Scribn. Bull. Torrey Club 17: 229. pl. 107, 108. 
1890, Pringle’s no. 2559 in U. S. National Herbarium is a duplicate of the type. 
Pentarrhaphis geminata Hack. & Scribn. Bull. Torrey Club 17: 230. 1890. A name 
only. 
DESCRIPTION. 
An erect, smooth, cespitose perennial, about 30 cm. high, with the habit of well- 
developed plants of B. trinii, but larger throughout; culms mostly erect, but in some 
Fia. 2l.—Pentarrhaphis polymorpha. a, Spike displayed; 6, c, lemma and palet of first floret; d, e, 
lemma and palet of second floret. a, Scale 5; b-e, scale 7.5. From Pringle 2559. 
specimens inclined to be slightly geniculate; upper blades sparse, flat, and short, 
the lower more abundant and longer, 5 to 10 em, long and about 1 mm. wide, bearing 
a few minute, scattered hairs on both surfaces; sheaths striate, smooth, narrow, the 
ligule reduced to a ciliate fringe; panicle racemose, the rachis wavy or zigzag; spikes 
4 to 8, triangular, 6 to 10 mm. long, purplish in all the specimens at hand; spikelets 
with backs together, 2-flowered, the lower floret pistillate, the upper staminate, with 
a bifid or undivided awn-like rudiment of a third; glumes narrow, the lower reduced 
to little more than an awn about 4 mm. long, the upper wider, keeled, notched above, 
5 to6mm. long; lemma.5 to 6mm. long, including the 3 nearly equal awns, the glumes 
and lower lemma covered with white hairs 1 mm. long; palet 3 to 4 mm. long, deeply 
