GRASS FAMILY. 



5. Poa laxa Haenke. Wavy Meadow-grass. Mountain Spear-gnus. 



(Fig. 463.) 



Poa laxa Haenke, in Jirasek, Beob. Riesengeb. 118. 



1791. 



Smooth and glabrous, culms i tall or less, erect, 

 simple. Sheaths often overlapping; ligulc about 

 \" loug; leaves \'-$' long, ^"-i" wide, acumi- 

 nate; panicle \'-$' in length, the branches usually 

 erect, sometimes ascending, \' long or less; spike- 

 lets 3-5-flowered, 2 // -2j" long; lower scales usu- 

 ally 3-nerved, acute, glabrous, rough on the keel 

 at its apex; flowering scales i^'-i^" 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 I,. Alpine Spear-gran. 



(Fig. 4 < 



Poa alpina L. Sp. PI. 67. 1753. 



Smooth and glabrous, culms 4 / -i8' tall, erect, 

 simple. Sheaths shorter than the internodes; ligule 

 i" long, truncate; leaves i'-3' long, i"-a" wide, 

 abruptly acute; panicle I'-j' in length, the branches 

 generally widely spreading, i' long or less; pikrleU 

 3-5-flowered, 2%"-$''' long; lower scales broad, gla- 

 brous, rough on the keel, acute; flowering scale* 

 about 2" long, obtuse, pilose for half their length. 

 pubescent between the nerves toward the base. 



Labrador to Alaska, south to QucU'c. Ijikc Superior. 

 and in the Rocky Mountains ti> Colorado. Alx> in nurope 

 and Asia. Summer. 



7. Poa cenisia All. Arctic Spear-grass. (Fig. 465.) 



Poa cenisia All. Auct. Fl. Fed. 40. 1789. 



Smooth and glabrous, culms 4 / -i5 / tall, erect, slen- 

 der, simple. Sheaths shorter than the internodes; lig- 

 ule \" long or less, truncate; leaves i'-4' long, J^'-i" 

 wide; panicle i'-4' in length, open, the branches gen- 

 erally widely spreading and more or less flexuous, i'- 

 2 l / 2 ' long; spikelets 3-5-flowered, 2%"-3%" long; 

 lower scales acute or acuminate, i-3-nervcd; flowering 

 scales about i" 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. 

 Summer. 



Also in Europe. 



