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



% — Rocky alpine summits, Montana to Washington, south to 

 Nevada (Mount Rose) and California (fig. 247). 



55. Poa lettermani Vasey. (Fig. 248.) In low lax tufts; culms 

 mostly less than 10 cm tall, usually scarcely exceeding the blades; 

 ligule 1 to 2 mm long; blades 

 lax, usually not more than 1 

 mm wide; panicle narrow, con- 

 tracted, 1 to 3 cm long; spikelets 

 3- or 4-flowered, 4 to 5 mm long ; 

 glumes equal, somewhat acumi- 

 nate, about as long as the first 

 and second florets ; lemmas erose 

 at summit, 2.5 to 3 mm long. 

 % — Rocky alpine summits, 

 British Columbia, Washington, 

 Colorado (fig. 249). 



56. Poa leibergii Scribn. 

 Leibergbluegrass. (Fig.250) 

 Usually densely tufted; culms 

 10 to 30 cm tall, erect; ligule 1 

 to 2 mm long; blades mostly 

 basal, firm, involute, usually 

 less than 10 cm long; panicle 

 narrow, 2 to 5 cm long, often 

 purple, the branches short, ap- 

 pressed or ascending; spikelets 2- to 4-flowered, 4 to 

 6 mm long; lemmas 3 to 4 mm long, smooth or 

 scaberulous. % — Alpine meadows and sterile 

 gravelly alpine flats, eastern Oregon and the Sierras 

 of California. 



6. Scabrellae. — Perennials, without rhizomes, tufted, with numerous 

 basal leaves; spikelets little compressed, narrow, much longer 

 than wide; lemmas convex, crisp-puberulent 

 on the back towards the base, the keels ob- 

 scure, the marginal and intermediate nerves 

 usually faint. The whole group of Scabrellae 

 is made up of closely related species which 

 appear to intergrade. 

 57. Poa scabrella (Thurb.) Benth. Pine blue- 

 grass. (Fig. 251.) Culms erect, 50 to 100 cm 

 tall, usually scabrous at least below the panicle; 



Figure 246.— Poa pringlei. 

 Plant, X 1; floret, X 10. 

 (Henderson 3080, Idaho.) 



Figure 248.— Poa letter- 

 mani. Plant, X 1; floret, 

 X10. (Letterruan, Colo.) 



Figure 247.— Distribution 

 of Poa pringlei. 



Figure 249— Distribution 

 of Poa lettermani. 



w A M 



Figure 250.— Poa leibergii. 

 Plant, X l; floret, X 10. 

 (Type.) 



sheaths scaberulous; ligule 3 to 5 mm long; blades mostly 

 basal, 1 to 2 mm wide, lax, more or less scabrous; panicle narrow, 

 usually contracted, sometimes rather open at base, 5 to 12 cm long; 



