648 POACEiE. 



to ail emiity glume. Empty glumes firm, narrowly linear, 1-15-5- 

 norved, short- or long-awiieil, persistent, all those at one node 

 resembling an involucre, rarely the glumes split into many awns; 

 ilorul glume sliorter, oblong or lanceolate, round on the back, 5- 

 nerved, obtuse or acute, awned or awnless; palea as long as the 

 lloral glume or shorter, 2-keeled. Stamens 3. Styles very short, 

 distinct, stigmas feathery. (J rain ol)long, hairy at the apex, grooved 

 on tlio inside, adiiering to the palea. 



Perennial grasses, xisually with broad Hat or firm convolute blades. 

 Spikes terminal, cylindrical, compact, often covered witli many awns, 

 rachis breaking in pieces or not, densely or loosely niany-fiowered. 



Species '-I't-'M), belonging to the temperate regions of Europe, 

 is-.i, and North America. 



Eh/iiius i^ distinguished from Hordeitni in having two or more 

 flowers to each spikelet, and is distributed into three sections: 



I. Sif anion, Rafin. PoIyaHf/icri/x Nees. Kachis articulate; 

 floral glume usually 15-awned. 



3. CUnchjim Griseb. l{a(;iiis continuous; spikelets usually 2 

 only at each notch, floral glume witii one long awn. 



3. rsaiiinu'hjiia ( i riseb. Tall rigid species, often with more than 

 two spikelets to each notcli ; floral glume unawned or with only 

 very short awnlikc points. 



A. Spike soft, ciliate, awn short or none 1,2, .'{,4 



B. Spike smooth or hirsute, awns iu)ne or very short. . 5, (5, 7 



C. Glumes awned ("■) 



a. Some of the empty glumes divided 1', S, 9 



a. Empty glumes not divided (b) 



b. Spike rigid, upright (c) 



c. Spike stout, partly included 10 



c. Spike narrow, exserted 11 



c. Spike stout, short, exserted 12 



b. Spike exserted, usually nodding (d) 



d. Spike large, 10-15 cm. long, floral glume often 

 flexuose l-^ 



d. Spike more slender, awns more slender. ' . 14 

 d. Spike dense, villous, awns stniight 15 



