436 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



lemma 6 to 8 mm long, about as in S. viridula; awn 2 to 3 cm long, 

 rather obscurely twice-geniculate. % (S. vaseyi Scribn.)— Dry plains 

 and hills and dry open woods, Colorado to northern Mexico (fig. 923). 

 Said to act as a narcotic on animals that graze upon it, especially 

 affecting horses. 8 



27. Stipa columbiana Macoun. Columbia needlegrass. (tig. 

 924.) Culms mostly 30 to 60 cm tall, sometimes as 

 much as 1 m; sheaths naked at the throat; ligule 1 to 

 2 mm long; blades 10 to 25 cm long, 1 to 3 mm wide, 

 mostly involute, especially on the innovations, those 

 of the culm sometimes flat; panicle 5 to 15 cm long, 

 narrow, mostly rather dense, often purplish; glumes 



about 1 cm long; lemma 6 to 7 

 mm long, pubescent as in S. viri- 

 dula, the body narrower, the 

 callus sharper; awn 2 to 2.5 cm 

 long, twice-geniculate. 01 (S. 

 minor Scribn.) — Dry plains, 

 meadows, and open woods, at 

 medium and high altitudes, Wy- 

 oming to Yukon Territory, 

 south to Texas and California (fig. 925). Differing 

 from S. viridula in the glabrous throat of the sheath 

 and in the shape of the fruit. 



Stipa columbiana var. nelsoni (Scribn.) Hitchc. 

 Differing in its usually larger size, often as much as 1 

 m tall, the broader culm blades, and the larger and 

 denser panicle; lemma 6 to 7 mm long; awn as much as 3.5 cm long, 

 sometimes longer. % — Alberta to Washington, south to Colorado 

 and Baja California. 



28. Stipa lettermani Vasey. Letterman needlegrass. (Fig. 926.) 

 Resembling small forms of S. columbiana; culms often in large tufts, 

 30 to 60 cm tall; blades slender, involute; panicle slender, narrow, 



Figure 923.— Distribution of 

 Stipa robusta. 



Figure 924.— Stipa 

 columbiana. Pani- 

 cle, X Yi, lemma, X 5. 

 (Nelson 7478, Wyo.) 





Figure 925.— Distribution of 

 Stipa columbiana. 



Figure 926.— Stipa 

 lettermani. Flo- 

 ret, X 1; lemma, 

 X 5. (Letterman 

 102, Idaho.) 



Figure 927.— Distribution of 

 Stipa lettermani. 



loose, 10 to 15 cm long; glumes about 6 mm long; lemma 4 to 5 mm 

 long, slender and more copiously hairy than in S. columbiana; awn 

 1 .5 to 2 cm long. % — Open ground or open woods at upper altitudes, 

 Wyoming to Montana and Oregon, south to New Mexico and Cali- 

 fornia (fig. 927). 



8 Contr. U.S. Nat. Herb. 24: 252. 1925. 



