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. 

 long, 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. (Figuee 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. Z%.—Bouleloua breviseta. a, Spikelet; 6, 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 " gyp " grass. It is a tough, wiry species, but is nevertheless utilized to a 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. Havard, western Texas, 1881; Nealley 785; Wooton 64 Otero 

 County, New Mexico; and Bailey 340, Boquillas, Texas, are representative. 



