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. 



17. STIPA, L. 



Spikelet composed of one stalked bisexual flower; 

 flowering glume with a twisted awn. 



5. 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^E. 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. 



1 8. AlRA, 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. prcecox, L. ; panicle com- 

 pressed, spike -like; sandy places; Valais, Piedmont, 

 Pyrenees. A . caryophyllea, L. ; panicle spreading, stem 

 very slender; sandy places. A. multiculmis, Dum. ; 

 similar, but spikelets smaller, more crowded. 



B. Rachis not produced; awn nearly straight (Des- 

 champsia, Beauv.): A. ccespttosa, L. ; panicle pyramidal; 

 moist, frequent. A. flexuosa, L. ; panicle very lax, 



