130 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Panicles close. 



Lemmas scabrous; leaves very 



scabrous 30. P. cottoni. 



Lemmas smooth ; leaves smooth. "iX. P. cusicMi. 

 Leaves not filiform. 



Stems low, 5 to 20 cm. high; grasses 

 of the highest mountains. 



Leaves soft: panicle purple, very 



short: plants .5 to 10 cm. high. 32. P. lettermani. 

 Leaves rather rigid; panicle pale, 

 narrow, elongated; plant 10 to 



20 cm. high 33. P. sulcsdorfii. 



Stems taller, usually 20 to 40 cm. 

 high; mostly grasses of rupestrine 

 habitat. 



Panicle close, erect; leaves flat. 

 Lemmas pubescent at base; 

 leaves rather narrow, some- 

 times folded 21 . P. sandbergii. 



Lemmas glabrous: leaf 

 blades broader. 



Leaf blades soft 22. P. jmddensw. 



Leaf blades firm, veiy 



short 23. P. curtifolia. 



Panicles loose; leaves narrow, 

 flat or involute. 



Ligules of the sterile shoots 

 obsolete; of the culm leaves 



short and truncate 24. P. mnUnomae. 



Ligules well developed on all 

 the leaves. 



Low plants 5 to 10 cm. 

 high; panicle small, 

 with divaricate rays 

 and few spikelets. . . . 25. P. vaseyocJdoa. 

 Taller; 10 to 30 cm. 

 high ; panicle less 

 spreading, with many 

 spikelets. 



Panicle loose; 

 glumes thin, 



blades involute. . 2G. P. (jrnciUhna. 

 Panicle close; 

 glumes firm, 

 blades flat 27. P. saxatili'f. 



1. Poa annua L. Sp. PI. 1: 68. 1753. 



TS-PE locality: "Habitat in Europa ad vias. " 



Specimens examined: Near Ellensburg, Piper 2617; Vasey 181; North Yakima, Watt, 

 August, 1895; Southbend, Spillman, August 17, 1899; Steptoe, Vasey 1; Pullman, Piper 

 2769. 



Abundantly introduced, but in some localities apparently native. 



2. Poa compressa L. Sp. PL 1: 69. 1753. C.\n.\d.\ eluegrass. 

 Type locality*: "Habitat in Europae et Americae sepicntrionalis siccis, muris, tectis." 



