406 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
in size upward, the last sometimes faced by a small l-awned scale, the whole so 
congested as to appear like a bunch of awns, and borne upon a short, naked stipe 
about 1 mm. long; caryopsis 1.25 mm. long, ovate, flattened on the back, the very 
small scutellum covering only one-fourth or one-fifth of the ventral surface. (I1a- 
URE 54.) 
In general appearance, especially as to inflorescence this species resembles Lep- 
tochloa, but the floral characters are those of Bouteloua. The basal portion of the 
plant resembles that of Muhlenbergia pungens Thurb. 
HERBARIUM SPECIMENS, 
Sourn America: Stuckert 10277a, in Herb. Argent.; 694, in Kneucker’s Gram. Exs. 
from Argentina, Elliott 510, Chile. Benivati 12687 in Kurtz, Herb. Argent. 
26. Bouteloua acuminata (Fourn.). 
Atheropogon acuminatus Fourn. Mex. Pl. 2: 139. 1881. The specimens cited, 
Liebmann 583, from Mirador, and Liebmann 584, from Potrero de Consoquitla, Mex- 
ico, have not been examined. My knowledge of the species is based upon Palmer’s 
no. 1655, concerning the identity of which there appears to be no doubt. 
DESCRIPTION, 
A stout, erect, smooth, cespitose perennial, resembling B. curtipendula in habit 
and general appearance; culms erect, comparatively stout, about 50 cm. high, leafy 
to the top, mostly unbranched; sheaths striate, 
close; blades broad, flat, often 5 mm, wide and 
25 cm. long, striate, smooth with serrate edge, 
and conspicuous, long, dusky, papillose hairs on 
the upper surface at the base, the ligular mem- 
brane with a few scattered hairs of the same 
nature; panicle racemose, often 25 cm. long; 
spikes numerous, 30 to 60, distinctly bilateral 
but the peduncles so curved as to appear 
unilateral toward maturity; spikelets 6 to 15, 
loosely and indistinctly or not at all pectinate, 
consisting of 1 floret and a rudiment; glumes 
hispid, keeled, the first acuminate, about 2 
mm. long, the second short-awned, about 3 
at mm. long; lemma minutely pubescent, shortly 
Fic. 55.—Boutelowa acuminata. a, Spikelet; 3-aristate, the central awn 0.5 mm. or less 
b,c, lemma and palet of first floret; d, rudi- longer than the lateral, about 4 mm, long; 
ment. @, Scale 7.5; b-d, scale 10. From palet, acuminate, smooth, about 2.5 mm. long; 
Palmer 1655. . 2 . ; 
rudiment reduced to a single, hispid, delicate 
awn, about 1.5 mm. long; caryopsis not seen, (FicureE 55.) 
In general habit this very closely resembles B. curtipendula, but the spikes are 
very different, although exactly the same in arrangement. They are smaller and 
apparently more numerous. Indeed, one might describe the species as B. curti- 
pendula with small delicate spikes of rather loosely arranged spikelets, only a fourth 
the size of those of that well-known species. 
Palmer’s 1655, cited above, of which there are two sheets in the National Herba- 
rium, is from Lodiego, Sonora, Mexico, collected October 9 to 15, 1891. It is said 
to grow in large bunches on the mountain sides, 
