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



2 to 5 cm. long, often purple, the 

 branches short, appressed or ascend- 

 ing; spikelets 2- to 4-flowered, 4 to 

 6 mm. long; lemmas 3 to 4 mm. long, 

 smooth or scaberulous. % — Al- 

 pine meadows and sterile gravelly 

 alpine flats, Idaho, eastern Oregon, 

 and the Sierras of California. 



7. Scabrellae. — Perennials, without 

 rhizomes, tufted, with numerous 

 basal leaves; spikelets little com- 

 pressed, narrow, much longer 

 than wide; lemmas convex, crisp- 

 puberulent on the back towards 

 the base, the keels obscure, the 

 marginal and intermediate nerves 

 usually faint. The whole group 

 of Scabrellae is made up of 

 closely related species which 

 appear to intergrade. 



62. Poa scabrella (Thurb.) Benth. 

 ex Vasey. Pixe bluegrass. (Fig. 

 175.) Culms erect, 50 to 100 cm. tall, 

 usually scabrous, at least below the 

 panicle; sheaths scaberulous; ligule 



3 to 5 mm. long; blades mostly basal, 

 1 to 2 mm. wide, lax, more or less 

 scabrous; panicle narrow, usually con- 

 tracted, sometimes rather open at 

 base, 5 to 12 cm. long; spikelets 6 

 to 10 mm. long; glumes 3 mm. long, 

 scabrous; lemmas 4 to 5 mm. long, 

 crisp-puberulent on the back toward 

 base. % — Meadows, open woods, 

 rocks, and hills, at low and medium 

 altitudes, western Montana and Col- 

 orado to Washington and California; 

 Baja California. A form like P. scab- 

 rella in other respects but with smooth 

 lemmas has been differentiated as P. 

 limosa Scribn. and Will. — California 

 (Mono Lake and Truckee). 



63. Poa gracillima Vasey. Pacific 

 bluegrass. (Fig. 176.) Culms rather 

 loosefy tufted, 30 to 60 cm. tall, 

 usually decumbent at base; ligule 2 

 to 5 mm. long, shorter on the innova- 

 tions; blades flat or folded, lax, from 

 filiform to 1.5 mm. wide; panicle 

 pyramidal, loose, rather open, 5 to 

 10 cm. long, the branches in whorls, 

 the lower in twos to sixes, spreading 

 or sometimes reflexed, naked below; 



spikelets 4 to 6 mm. long; second 

 glume 3 to 4 mm. long; lemmas 

 minutely scabrous, crisp-pubescent 

 near base, especially on the nerves. 

 % — Cliffs and rocky slopes, Al- 

 berta to Alaska, south to Colorado 

 and the southern Sierras of Cali- 

 fornia. Poa tenerrima Scribn. is a 

 form with open few-flowered panicles; 

 southern Coast Ranges, California; 

 P. multnomae Piper is a loose lax 

 form in which the ligules on the 

 innovations are short and truncate; 

 wet cliffs, Multnomah Falls, Oreg. 



64. Poa secunda Presl. Saxdberg 

 bluegrass. (Fig. 177.) Culms erect 

 from a dense, often extensive, tuft of 

 short basal foliage, commonly not 

 more than 30 cm., but sometimes up 

 to 60 cm. tall; ligule acute, rather 

 prominent; blades rather short, soft, 

 flat, folded, or involute; panicle nar- 

 row, 2 to 10 cm. long, the branches 

 short, appressed, or somewhat spread- 

 ing in anthesis; spikelets about as 

 in P. gracillima. % (P. sandbergii 

 Vasey.) — Plains, diy woods, rocky 

 slopes, at medium and upper alti- 

 tudes, but not strictly alpine, North 

 Dakota to Yukon Territory, south 

 to Nebraska, New Mexico, and 

 southern California; Chile. 



65. Poa canbyi (Scribn.) Piper. 

 Canby bluegrass. (Fig. 178.) Green 

 or glaucous; culms 50 to 120 cm. tall; 

 ligule 2 to 5 mm. long; blades flat 

 or folded; panicle narrow, compact 

 or rather loose, 10 to 15 cm. long, 

 sometimes as much as 20 cm., the 

 branches short, appressed; spikelets 

 3- to 5-flowered; lemmas more or 

 less crisp-pubescent on lower part of 

 back. % (P. lucida Vasey; P. laevi- 

 gata Scribn.) — Sand}^ or dry ground, 

 Michigan (Isle Royale) and Minne- 

 sota to Yukon Territory, south to 

 Colorado and eastern Washington to 

 northern California; Quebec. Poa 

 lucida has a slender but somewhat 

 loose pale or shining panicle; P. 

 canbyi has a denser, compact, dull 

 green panicle, but the two forms 

 grade into each other. Poa lucida is 



