184 THE FLORA OF THE ALPS 
16. GASTRIDIUM, Beauv. 
Empty glumes large, boat-shaped, flowering glume 
minute, 4-toothed. Not alpine; annual. 
G. lendigerum, Gaud. ; panicle glistening, spikelets with 
a long awn; sandy places, rare ; Geneva, Como, Pyrenees. 
Ly so VIPAS as 
Spikelet composed of one stalked bisexual flower; 
flowering glume with a twisted awn. 
S. pennata, L.; awn 8-12 in. long, plumose; high, 
rocky. S. capillata, L.; awn half as long, rough, not 
plumose; high, rocky; Southern Switzerland, Jura, 
Dauphiny, Pyrenees. 
Tribe AVENE&.—Spikelets in panicles, 2-, rarely 3- 
or 4-flowered; glumes 4 or more, the two lowest empty ; 
flowering glumes with twisted awns. Genera 18-22. 
18. AIRA, L. 
Spikelets 2-flowered; flowers all perfect, or the upper 
ones imperfect. 
A. Rachis of spikelet not produced beyond the upper- 
most flowering glume:—A. precoxr, L.; panicle com- 
pressed, spike-like; sandy places; Valais, Piedmont, 
Pyrenees. A. caryophyllea, L.; panicle spreading, stem 
very slender; sandy places. <A. multeculmis, Dum.; 
similar, but spikelets smaller, more crowded. 
B. Rachis not produced; awn nearly straight (Des- 
champsia, Beauv.):—A. cespitosa, L.; panicle pyramidal ; 
moist, frequent. A. flexuosa, L.; panicle very lax, 
