538 POACE^. 



Mexico, PringU 4307. 



Under dry cool cliffs. 



14. P. nervosa (Hook.) Vasey, 111. 1^. A. Gr. 2: 81 (1893). Fes- 

 tuca nervosaUook. Fl. Bor. Am. 2, 251, 232 (1840). 



Culms rather slender, 45-75 cm. high. Blades of sterile shoots 

 15-24 cm. high, those of the culm about 3, upper ligule rounded, 

 1.5 mm. long; blades erect, fiat, 3-7 cm. long, 2-4 mm. wide. 

 Panicle thin, pyramidal, 5-12 cm. long, rays spreading or somewhat 

 erect, the lower in twos to fives, the longest 6-8 cm. long, each 

 bearing 3-6 sj^ikelets near the apex. Spikelets 3-8-flowered, flat- 

 tish, 4-5 mm. long, first empty glume 3 mm. long, 1-nerved, sec- 

 ond 3-nerved, 3.3-3.6 mm. long; floral glume linear-lanceolate, 5- 

 nerved, 3.5-4.5 mm. long, scabrid on the nerves; palea as long as 

 its glume. Ovary linear, 1.5 mm. long. Stigmas 3 mm. long. 



Montana, Cmibij cf- Scribner 379, 395; Washington, Yaseij; 

 Oregon (Colvimbia River), Howell. 



Alaska to Oregon. 



Yar. Tracyi (Vasey), Poa Tracy i Yasey, Contrib. U. S. Xat. 

 Herb. 1 : 276 (1893). 



Floral glume webbed at base, pubescent on the lateral nerves 

 and on the keel. 



New Mexico (Raton), *S'. M. Tracy. 



15. P. acuminata Scribn. ined. 



Tufted, erect, 25-35 cm. high, smooth throughout. Sheaths of 

 culm 3 in number, ligule truncate, 2 mm. long; blades flat or con- 

 duplicate, abruptly pointed, 3-6 cm. long, 3-4 mm. wide. Panicle 

 ovoid, 7-10 cm. long, rays slender, capillary, flexuose, 4-5 cm. long, 

 bearing on the outer half 10-16 spikelets. Spikelets much com- 

 pressed, ovAte to linear, about 5 mm. long, 3-5-flowered, tinged with 

 jjurple and brown; first empty glume 3 mm. long, oval-lanceolate, 

 1-nerved, second 3.5 mm. long, oval-acute, 3-nerved; floral glume 

 3-3.5 mm. long, the keel and lateral nerves clothed with webby 

 hairs for two-thirds of their length, ovate, obtuse when spread: 

 palea 2.5 mm. long. 



Montana, F. Tweedy 639 in 1885, 1027 in 1886 for U. S., 

 Dept. Agricul. 



