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



Figure 183.— Distribution of 

 Poa cuspidata. 



Figure 182. — Poa cuspidata. Panicle, 

 X 1; floret, X 10. (Smith 27, Pa.) 



2 to 4 mm wide, the basal often elongated; panicle pyramidal or 

 oblong-pyramidal, open, the lowermost branches usually in a whorl 

 of 5, ascending or spreading, naked below, normally 1 central long 

 one, 2 shorter lateral ones and 2 short intermediate ones; spikelets 



crowded, 3- to 5-flowered,3 to 6 mm long; 

 lemmas copiously webbed at base, silky- 

 pubescent on lower half or two-thirds of 

 the keel and marginal nerves, the inter- 

 mediate nerves distinct, glabrous. % — 

 Open woods, mead- 

 ows, and open 

 ground, widely dis- 

 tributed through- 

 out the United 

 States and north- 

 ward, except in 

 arid regions, found 

 in all the States 



(but not common in the Gulf States) 

 and at all altitudes below alpine re- 

 gions; introduced from Europe. Blue- 

 grass is commonly cultivated for lawns 

 and pasture in the humid northern 

 parts of the United States. 

 18. Poa cuspidata Nutt. (Fig. 182.) Culms in large lax tufts, 

 30 to 50 cm tall, scarcely longer than the basal 

 blades; blades lax, 2 to 3 mm wide, abruptly cus- 

 pidate-pointed; panicle 7 to 12 cm long, open, the 

 branches mostly in pairs, distant, spreading, spikelet- 

 bearing near the ends; spikelets 3- or 4-flowered; 

 lemmas 4 to 6 mm long, tapering to an acute apex, 

 webbed at base, sparingly pubescent on the keel 

 and marginal nerves, the in- 

 termediate nerves distinct, 

 glabrous. % (P. brachyphylla 

 Schult.) — Rocky woods, J 

 New Jersey to Ohio, south 

 to Georgia and eastern Ten- 

 nessee (fig. 183). 



19. Poa arida Vasey. Plains 

 bluegrass. (Fig. 184.) Culms 

 erect, 20 to 50 cm tall; blades mostly basal, firm, | 

 folded, usually 2 to 3 mm wide, a single culm 

 leaf usually below the middle of the culm, its blade 

 short; panicle narrow, somewhat contracted, 2 to 

 10 cm long, the branches appressed 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 f or less villous 

 on the lower part of the intermediate nerves. % (P. sheldoni 

 Vasey.) — Prairies, plains, and alkali meadows, up to 3,000 m, 

 Manitoba to Alberta, south to western Iowa, Texas, and northern 

 Arizona (fig. 185). 



Figure 185.— Distribution of 

 Poa arida. 



Figure 184. — Poa 

 arida. Panicle, X 

 1; floret, X 10. 

 (Jones, Colo.) 



