208 
GRAMINEAE. 
20. Poa arida Vasey. Prairie Spear-grass. (Fig. 478.) 
Poa andina Nutt.; S. Wats. Bot. King’s Exp. 388. 1871. Not 
Trin. 1836. 
Poa arida Vasey, Contr. U. S. Nat. Herb. 1: 270. 1893. 
Culms 1°-2° tall, erect, rigid, simple, smooth and gla- 
brous. Sheaths usually overlapping, smooth or some- 
what roughish; ligule 1/’-2’’ long, acute; leaves smooth 
beneath, rough above, 14’/-1’’ wide, flat or folded, pun- 
gently pointed, those of the culm 4/1’ long, erect, the 
basal leaves 3/-6’ long; panicle contracted, 2/-5’ in 
length, the branches erect, spikelet-bearing nearly to the 
base, 114’ long or less; spikelets 4-7-flowered, 214//-334// 
long; lower scales nearly equal, acute, 3-nerved; flower- 
ing scales 1'4’/-2’/ long, erose-truncate at apex, strongly 
silky-pubescent on the nerves for half their length, the 
lower part very pubescent between the nerves; interme- 
diate nerves very obscure. 
On prairies, Kansas to Utah, north to British America. 
July-Sept. 
21. Poa Buckleyana Nash. Buckley’s Spear-grass. (Fig. 479.) 
Not A. Rich. 1851. 
Poa tenuifolia Buckley, Proc. Acad. Phila. 1862: 96. 1862. Li j 
Poa Buckleyana Nash, Bull. Torr. Club, 22: 465. 1895. 
Culms 6/—2° tall, erect, rigid, simple, smooth and 
glabrous. Sheaths shorter than the internodes; ligule 
2//-3// long, acute; leaves 1/4’ long, about 1’’ wide, 
erect, flat, or becoming inyvolute, smooth or rough; 
panicle 1/—4’ in length, contracted, the branches erect, 
114’ long or less, spikelet-bearing nearly to the base; 
spikelets 2-5-flowered, 2’’-3’’ long; scales acute, the 
lower nearly equal, scabrous on the keel; flowering 
scales about 2/’’ long, obtuse or acutish, sparingly 
pubescent on the nerves below, sometimes slightly 
hispid toward the base between the nerves. 
Kansas to California, north to British America. July- 
Aug. 
22. Poa glumaris Trin. Large-flowered Spear-grass. (Fig. 480.) 
YZ 
WZ 
NY, | ZEEE 
LZ 
Poa glumaris Trin. Mem. Acad. St. Petersb. (VI.) 1: 379. 
1831. 
Smooth and glabrous, culms 6’—3° tall, erect or as- 
surgent, simple. Sheaths loose, usually shorter than 
the internodes; ligule '%’’ long, truncate; leaves 
4/-10’ long, 1’/-4’’ wide; panicle 4’—10’ in length, the 
branches erect or ascending, 1/-2’ long; spikelets 3-5- 
flowered, 4’’-6’’ long; lower scales about equal, acute, 
slighty scabrous on the keel, the first 1-3-nerved, the 
second 3-nerved, rarely 5-nerved; flowering scales 3//— 
4’’ long, usually acutish, scabrous, 5—7-nerved, pubes- 
cent at base and on the lower part of the midnerve and 
lateral nerves, not webbed. 
Anticosti Island and Nova Scotia to Quebec and Alaska. 
Summer. 
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