of the internerves, the base often webbed. P. arctica of Am. Auth., not R. Br. 



In wet meadows, shallow water of lakes and ponds, and on wet stream banks, 

 mostly above timberline, in N. M. (Rio and Taos cos.); from arctic regions s. 

 to N.S. and in the Rocky Mts. to N.M., Nev. and Calif. 



5. Poa reflexa Vasey & Scribn. Nodding bluegrass. 



Culms solitary or in small tufts, erect, 2-4 dm. tall; blades rather short, 1-4 

 mm. wide; panicle nodding, 5-15 cm. long, the branches naked below, solitary, 

 in pairs or in threes, the lower usually reflexed, sometimes strongly so; spikelets 

 2- to 4-flowered; lemmas about 3 mm. long, oblong-elliptic, webbed at base, villous 

 on keel and marginal nerves and sometimes on intermediate nerves. 



In wet meadows and on wet stream banks, in N. M. (Santa Fe Co.) and 

 Ariz. (Coconino Co.); Mont, to e. B.C., s. in mts. to N.M. and Ariz. 



6. Poa leptocoma Trin. Bog bluegrass. 



Culms slender, solitary or few in a tuft, 2-5 dm. tall, often decumbent at 

 the base; sheaths usually slightly scabrous; ligule acute, the uppermost 3-4 mm. 

 long; blades short, lax, mostly 2-4 mm. wide; panicle nodding, delicate, few- 

 flowered, the branches capillary and ascending or spreading, subflexuous, the 

 lower mostly in pairs; spikelets narrow, 2- to 4-flowered; glumes narrow, acumi- 

 nate; lemmas 3.5-4.5 mm. long, acuminate, webbed at base, pubescent on the 

 keel and marginal nerves or sometimes nearly glabrous, the intermediate nerves 

 distinct. 



In bogs and wet meadows and wet places along streams, in N.M. {Hitchcock); 

 Alas., s. in mts. to N.M. and Calif. 



7. Poa palustris L. Fowl bluegrass. 



Culms loosely tufted, glabrous, decumbent at the flattened purplish base, 3-15 

 dm. tall; sheaths keeled, sometimes scaberulous; ligule 3-5 mm. long or only 1 

 mm. on the innovations; blades 1-2 mm. wide; panicle pyramidal or oblong, 

 nodding, yellowish green or purplish, 1-3 dm. long, the branches in rather distant 

 fascicles, naked below; spikelets 2- to 4-flowered, about 4 mm. long; glumes 

 lanceolate, acute, shorter than the first floret; lemmas 2.5-3 mm. long, usually 

 bronzed at the tip, webbed at base, villous on the keel and marginal nerves. 



Wet meadows and wet open soils, in N.M. (Hiichcook) and Ariz. (Graham 

 Co.); Nfld. and Que. to Alas., s. to Va., Mo., Neb., N.M., Ariz, and Calif.; 

 Euras. 



8. Poa interior Rydb. 



Tightly tufted perennial; culms numerous, 2-5 dm. long, about 1 mm. thick, 

 strictly erect; blades short, about 1 mm. broad, flat, erect; panicles 4-8 cm. 

 long, 1-2 cm. broad, rather dense, almost spiciform, strictly erect, the lower 

 node with 2 (rarely 3) strictly erect basally naked branches; spikelets crowded, 

 laterally compressed, 2- to 4-flowered; lowest lemmas 3-4 mm. long, keeled, 

 stramineous, firm, 5-nerved, the midnerve and marginal nerves pubescent at least 

 in the lower part, the intermediate nerves very obscure, the internerve areas 

 glabrous, the base with a weak tuft of long flexuous silky white hair. 



In water of streams, edge of lakes and ponds, and in marshes, in N.M. (San- 

 doval and Taos cos.) and Ariz. (Coconino Co.), reported to occur in Tex.; if 

 present then rare at highest elev. in the Trans-Pecos mts.. summer; forested mt. 

 slopes. Que. to B.C. and s. in the mts. to Ariz, and N.M. 



9. Poa nevadensis Vasey ex Scribn. Nevada bluegrass. 



Culms erect, 5-10 dm. tall; sheaths scabrous, sometimes only slightly so; 

 ligule about 4 mm. long, shorter on the innovations, decurrent; blades usually 

 elongate, narrow, involute, sometimes almost capillary, rather stiff; panicle narrow, 



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