2 54 



GRAMINEAE. 



VOL. I. 



4. Poa laxa Haenke. Wavy Meadow-grass. 

 Mountain Spear-grass. Fig. 607. 



P. laxa Haenke, in Jirasek, Beob. Riesengeb. 118. 1791. 



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

 simple. Sheaths often overlapping; ligule about i" 

 long; blades i'-3' long, i"-i" wide, acuminate; pan- 

 icle i '-3' in length, the branches visually erect, some- 

 times ascending, i' long or less; spikelets 3-5-flow- 

 ered, 2"-2\" long; lower scales usually 3-nerved, 

 acute, glabrous, rough on the keel at its apex ; flow- 

 ering scales ij"-i5" long, obtuse, 3-nerved, or some- 

 times 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 high mountains of 

 New England and New York. Also in Europe and Asia. 

 Summer. 



5. Poa alpina L, Alpine or Mountain Spear-grass. Fig. 608. 



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; blades i'~3' long, i"-2" wide, abruptly acute; 

 panicle i'~3' in length, the branches generally widely 

 spreading, i' long or less; spikelets 3-5-flowered, 2}"-3" 

 long; lower scales broad, glabrous, rough on the keel, 

 acute; flowering scales about 2" long, obtuse, pilose 

 for half their length, pubescent between the nerves 

 toward the base. 



Newfoundland and Labrador to Alaska, south to Nova 

 Scotia, Quebec, Lake Superior and Washington, and in the 

 Rocky Mountains to Colorado. Also in Europe and Asia. 

 Summer. 



6. Poa glauca Vahl. Glaucous Spear-grass. Fig. 609. 



Poa glauca Vahl, Fl. Dan. pi. 064. 1790. 



Poa caesia J. E. Smith, Eng. Bot. pi. 1770. 1807. 



Culms 6'-2 tall, erect, rigid, glabrous, somewhat 

 glaucous. Sheaths overlapping, confined to the lower 

 half of the culm; ligule i" long; blades i'-2' long, i" 

 wide or less, smooth beneath, scabrous above ; panicle 

 i '-3' in length, open, the branches erect or ascending, 

 i'-ij' long; spikelets 2-4-flowered, 2.\"-^" long; empty 

 basal scales acute, 3-nerved, glabrous, rough on the 

 upper part of the keel; flowering scales i|"-i|" long, 

 obtuse or acutish, rough, not webbed at the base, the 

 lower half of the midnerve and marginal nerves silky- 

 pubescent, the intermediate nerves obscure and occa- 

 sionally sparingly pubescent at the base. 



Greenland and Labrador to Maine and White Mountains 

 of New Hampshire and Minnesota. Also in Europe. July 

 and August. 



