380 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
DESCRIPTION. 
A stout, rigid, erect perennial, 25 to 40 cm. high, with branching, perennial culms, 
the internodes, when protected, covered with a thick, scaly bloom, cespitose, spread- 
ing by short, stout, scaly rootstocks; sheaths rather close, striate, covering nearly the 
entire internode; ligule sparingly ciliate-hairy; blades small, 3 to 6 cm. long, convolute, 
narrow, rigid, acuminate-pointed, bearing a few scattered hairs on the upper surface; 
spikes normally 2, often 1 and less frequently 3, linear-oblong, 2 to 2.5 cm. long, straight 
or slightly recurved; spikelets numerous, 30 to 45, pectinately arranged, about 3 mm, 
Jong, consisting of a lower perfect floret and a rudiment, with often a very small sec- 
ond rudiment; first glume 2 to 2.5 mm., the second 3 to 3.5 mm, long, nearly smooth; 
lemma about 5 mm. long, having 4 teeth and 3 awns of nearly equal length, pubescent; 
palet smooth, awnless, rudiment about 4.5 mm. long, of 3 hispid awns of about equal 
length and a rudimentary scale, all arising from a tuft of long, white hairs at apex of a 
stipe. (FicureE 36.) 
This is a very interesting species, apparently confined to the calcareous soils of the 
Rio Grande Valley and its tributaries. It is one of the important grasses upon the 
Fig. 36.—Bouteloua breviseta. a, Spikelet; b,c, lemma and palet of first floret; c, d, 
rudiments of second and third florets. a, Scale 7.5; b-d, scale 15. From Nealley 
669. 
white (gypsum) sands of southeastern New Mexico, where it often creeps into rather 
unstable earths, Good stands of the grass occur in the Pecos Valley upon soils con- 
taining 73.2 per cent calcium sulphate and 3.2 per cent calcium carbonate, according 
to the analysis of a sample collected in 1903 and submitted early in 1904 to the Bureau 
of Soils of the Department of Agriculture. In the Roswell district of New Mexico 
B. breviseta is very evidently confined to the gypsum deposits and is popularly known 
as “cyp”’ grass, It isa tough, wiry species, but is nevertheless utilized toa very large 
extent as a pasture grass. The amount of trampling which it endures is remarkable. 
The deposits of gypsum occur here between the water in and along the Pecos and the 
better grazing grounds upon the mesas beyond the bluffs. Because of this the tramp- 
ling across this deposit is very heavy. The tenacious character of the grass is strik- 
ingly exhibited in the regions of heaviest traveling. Having perennial culms it is of 
particular service during a prolonged drought. 
There are a number of specimens in the National Herbarium which correspond 
exactly with the type. Savard, western Texas, 1881; Nealley 785; Wooton 64 Otero 
County, New Mexico; and Bailey 340, Boquillas, Texas, are representative. 
