GRASS FAMILY. 203 
5. Poa laxa Haenke. Wavy Meadow-grass. Mountain Spear-grass. 
(Fig. 463. ) 
Poa laxa Haenke, in Jirasek, Beob. Riesengeb. 118. 
1791. 
Smooth and glabrous, culms 1° tall or less, erect, 
simple. Sheaths often overlapping; ligule about 
1’’ long; leaves 1/-3/ long, 14’/-1’’ wide, acumi- 
nate; panicle 1/-3/ in length, the branches usually 
erect, sometimes ascending, 1’ long or less; spike- 
lets 3-5-flowered, 2’’-214’ long; lower scales usu- 
ally 3-nerved, acute, glabrous, rough on the keel 
at its apex; flowering scales 114’/-134/’ long, ob- 
tuse, 3-nerved, or sometimes with an additional 
pair of obscure nerves, the midnerve pilose on the 
lower half, rough above, the lateral ones pilose for 
one-third their length. 
Greenland to Alaska, south to the mountains of New 
England, to Manitoba and in the Rocky Mountains to 
Colorado. Also in Europe and Asia. Summer. 
6. Poa alpina L. Alpine Spear-grass. 
(Fig. 464. ) 
Poa alpina V,. Sp. Pl. 67. 1753. 
Smooth and glabrous, culms 4/-18’ tall, erect, 
simple. Sheaths shorter than the internodes; ligule 
1/’ long, truncate; leaves 1/-3/ long, 1//-2/’ wide, 
abruptly acute; panicle 1/-3/ in length, the branches 
generally widely spreading, 1’ long or less; spikelets 
3-5-flowered, 214/’-3/’ long; lower scales broad, gla- 
brous, rough on the keel, acute; flowering scales 
about 2’’ long, obtuse, pilose for half their length, 
pubescent between the nerves toward the base. 
Labrador to Alaska, south to Quebec, Lake Superior, 
and in the Rocky Mountains to Colorado. Also in Europe 
and Asia. Summer. 
7. Poa cenisia All. Arctic Spear-grass. (Fig. 465.) 
Poa centsia All, Auct. Fl. Ped. 40. 1789. 
Smooth and glabrous, culms 4/-15’ tall, erect, slen- 
der, simple. Sheaths shorter than the internodes; lig- 
ule 1’’ long or less, truncate; leaves 1/-4’ long, %4//-1/’ 
wide; panicle 1-4’ in length, open, the branches gen- 
erally widely spreading and more or less flexuous, 1/— 
2'4’ long; spikelets 3-5-flowered, 2!4//-314’’ long; 
lower scales acute or acuminate, 1-3-nerved; flowering 
scales about 2’’ long, faintly 5-nerved, the nerves short- 
pilose on the lower half, minutely pubescent between 
the nerves, somewhat webbed at the base. 
Greenland and Labrador to Alaska. Also in Europe. 
Summer. 
