45 



and especially aloug the uanow, cartilaginous margius, strongly pilose above 

 and below. Branches of the panicle very short, slightly crowded, spikelets 

 obovate, about 2 mm. long. First glume less than 1 mm. in length, o-nerved; 

 second glume shorter than the dowering glume, 5-nerved; outer glumes all 

 obtuse, the third one empty. Flowering or fruiting glume about 2 mm. long, 

 strongly convex and deeply transversely rugose excepting near the slightly 

 apiculate apex. Palea trausveisely rugose and similar in texture to the tlower- 

 ing glume. Bristles 12 to 18 miu. long, strongly scabrous. 



(Growing under bushes in deep 

 ravines, Durango, Mexico (No. 

 879, E. Palmer, 1896.) 



This species is well marked by its 

 c o iH p a r a t i ^' e 1 y short and 

 broad leaves which are cor- 

 date at the base, and long, 

 widely spreading bristles. 



STIPA WILLIAMSII Scribn., 

 sp. n. (I'l. IV.) 



A rather stout, erect perennial, 7 

 to 9 dm. high, with rather 

 long. Hat leaves and strict 

 panicles, 17 to 22 cm. long. 

 Culms sometimes geniculate 

 at the lower nodes, pubescent 

 at least near the nodes. 

 Sheaths shorter than the inter- 

 nodes and softly pubescent, 

 at least the lower ones. 

 Ligule very short, auriculate. 

 Leaf-blades 15 to 30 cm. long, 

 2 to 6 mm. Avide, long atten- 

 uate pointed, pubescent on 

 the back, especially toward 

 the base, scabrous above. 

 Lower pauicle-brauchos 5 to 8 

 cm. long, the longer ones naked 

 below, shorter ones flower- 

 bearing to the base. Spike- 

 lets, exclusive of the awns, 

 about 6 mm, long. Empty 

 glumes lanceolate, with long- 

 acuminate hyaline tips, neaily 

 e(iual and a little exceeding 

 the dowering glume, the lirst 

 3-nerve(l, the second 5-nerved. 

 Flowering glumes about 6 



Fia.i.—I'anicuin wrighUanum Scribu.: a, h, c. various 

 views of tin- spikelet; d. tliinl kIuiiu-, nliowing small 

 palea; c, llouering, or fruiting glu7nc, suen from the back; 



mm. lon..rwith a Sharp-pointed /. Aoweriug glume, .seeu frou. tbo anterior side, showiu. 



callus, 1 mm. in length. 



palea. 



strongly pilose all over with appressed hairs and a distinct crown of hairs at 

 the apex. Palea pilose like the glume and about one-half its length. Awn 

 about 2.5 cm. long, once or twice geniculate and more or less flexuous, minutely 

 scabrous throughout. 

 Dry soil on the west side of Big Horn Mountain, near Monument Spring, Wyo., 

 altitude 2,200 to 2,400 meters (No. 2801, Thomas A. Williams, August 3, 1897); 

 Eocky knolls. Little Laramie River, Wyoming (No. 2234, Thomas A. Williams, 



