AVENE.E. 



363 



20-30 cm. high, with 



Delicate auuuals with the habit of Jira, having narrow csesjDi- 

 tose blades. Panicle slender, contracted, with capillary rays. 

 Species 2, found in the vicinity of tlie Mediterranean seaand north- 

 ward and introduced into other countries. 



The racliilla is continuous as in Deschampsia, but the genus is 

 readily distinguished by the peculiar club-shaped awn of the lloral 

 glume. 



1. W. CANESCENS Bemli. 1. c. Corynepliorus canescens Beauv. 

 Agrost. 159 (1812). 



Tufted glaucous or slightly purplish, 

 fine stiff convolute blades, the lower 5- 

 10 cm., those on the culm about 1 cm. 

 long. Panicle 4-6 cm. long. Spike- 

 lets about o mm. long; empty glumes 

 pointed, concealing the florets, awn 

 scarcely protruding; floral glume 1.5 

 mm. long. 



In sandy soil. Introduced into the 

 United States with grass-seed. 



76. (154). Deschampsia Beauv. 

 Agrost. 91, t. 8, /. 3 (1812). Airidinm 

 Steud. Syn. PI. Gram. 423 (1854). There are at least 10 other 

 synonyms. 



Spikelets 2-flowered, in a loose or rarely contracted panicle with 

 slender rays, racliilla articulate, hairy, more or less produced 

 between the floral glumes and beyond the upper one as a hairy 

 bristle, or rarely bearing an empty glume. Empty glumes keeled, 

 rather acute, the sides thinly scarious; floral glume membranous or 

 nearly hyaline, obtuse or truncate, 2-to several-toothed, with a fine 

 dorsal awn attached near the middle, the lower floret sessile, the 

 upper raised on a stipe; palea narrow, prominently 2-nerved, often 

 2-toothed. Stamens 3. Styles short, distinct. Grain enclosed, 

 but usually not adherent. Perennial grasses with the shining 

 spikelets of Ti'isetum and Aira, usually smaller than the former, 

 larger than those of the latter genus. There are about 20 species, 

 generally distributed over the temperate regions of the northern 



Fig. 64. — Weingcertneria 



canescens. Spikelet. 



(Scribner.) 



