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



panicle narrow, somewhat contracted, 

 2 to 10 cm. long, the branches ap- 

 pressed or ascending; spikelets rather 

 thick, 5 to 7 mm. long, 4- to 8-flow- 

 ered ; lemmas 3 to 4 mm. long, densely 

 villous on the keel and marginal 

 nerves and more or less villous on the 

 lower part of the intermediate nerves. 

 01 (P. sheldoni Vasey.) — Prairies, 

 plains, and alkali meadows, up to 

 3,000 m., Manitoba to Alberta, south 

 to western IoAva, Texas, and New 

 Mexico. 



21. Poa glaucifolia Scribn. and 

 Will. (Fig. 135.) Plants glaucous; 

 culms in loose tufts, 60 to 100 cm. 

 tall; blades 2 to 3 mm. wide; panicle 

 narrow, open, mostly 10 to 20 cm. 

 long, the branches usually in some- 

 what distant whorls, mostly in threes, 

 ascending, very scabrous, naked be- 

 low; spikelets 2- to 4-flowered; glumes 



Figure 135. — Poa glaucifolia. Panicle, X 1; floret, 

 X 10. (Rydberg 3288, Mont.) 



4 to 5 mm. long; lemmas about 4 mm. 

 long, villous on the lower half of the 

 keel and marginal nerves and more or 

 less so on the intermediate nerves be- 

 low. 01 — Moist places, ditches, 

 and open woods at medium altitudes, 

 British Columbia and Alberta through 

 Idaho to Minnesota, Nebraska, New 

 Mexico, Arizona, and Nevada. 



22. Poa arctica R. Br. Arctic 

 bluegrass. (Fig. 136.) Culms loosely 

 tufted, erect from a decumbent base, 



Figure 136. — Poa arctica. Panicle, X 1 ; floret, 

 (Sewall 244, Baflin Land.) 



X 10. 



10 to 30 cm. tall; ligule pointed, up to 

 4 mm. long; blades mostly basal, flat 

 or folded, mostly 2 to 3 mm. wide, one 

 short blade about the middle of the 

 culm ; panicle open, pyramidal, 5 to 10 

 cm. long, the lower branches usually 



2, spreading, sometimes reflexed, 

 bearing a few spikelets toward the 

 tip; spikelets 5 to 8 mm. long, 3- or 

 4-flowered ; lemmas densely villous on 

 the keel and marginal nerves and pu- 

 bescent on the lower part of the inter- 

 nerves, the base often webbed. Qi 

 (P. gray ana Vasey; P. aperta Scribn. 

 and Merr., a form with pale, rather 

 lax panicles longer than wide.) — 

 Meadows, mostly above timber line, 

 Arctic regions, south to Nova Scotia, 

 in the Rocky Mountains to Nevada 

 and northern New Mexico and in the 

 Cascades to Oregon; California (Inyo 

 County) . 



3. Palustres. — Perennials without 



creeping rhizomes; lemmas 

 webbed at base, glabrous, or pu- 

 bescent on the nerves. 

 23. Poa trivialis L. Rough blue- 

 grass. (Fig. 137.) Culms erect from a 

 decumbent base, often rather lax, 



