AGROSTIDE.E. 235 



late above the empty glumes, not exter.ding above the floret, floral 

 glume witli a miuute callus, usually bearded at the base. Empty 

 glumes 2, persistent, membranous or hyaline, often unequal, the 

 lower sometimes minute or obsolete, keeled, acute, mucronate, or 

 sometimes extending into a short awn, first 1-nerved. second 1-3- 

 nerved; floral glume 3-5-nerved. firm or slender, obtuse or acute, 

 2-toothed, mucronate or very often extending into a slender awn; 

 palea hyaline, 2-keeled. Stamens usually 3. Styles distinct, stig- 

 mas plumose. Grain narrow, subterete, enclosed by the floral glume 

 and palea, but not adherent. 



Grasses very variable in habit, rarely annual, culms often wiry, 

 leaf -blades often very thin. The genus includes 60 or more species. 

 most of which are peculiar to North America. Some are found in 

 South America, a few in Asia. 



Bentham observes: " They connect in many respects, Stijya with 

 Agrostis iX\)\iVO&c\\mg very nearly to the small-flowered ^iS'/f^^jre, though 

 having thinner fruiting glumes, and usually with a more or less 

 hairy rachilla. From Agrostis they may be distinguished by their 

 narrow oppressed fruiting glume witli a terminal, never dorsal, awn. 

 A very few unawned species are nearly allied to Epicampes. The 

 inflorescence is very variable." 



A. First glume 2-nerved, second 1-nerved, floral glume 3- 



nerved (a) 



a. Ligule a mere ring, empty glumes 2-3 mm. long, floral 



glume 2.5-3 mm. long 1 



a. Ligule 0.5-1.5 mm. long, empty glumes 3-4 mm. long, 

 floral glume 3 mm. long 2 



B. First glume sometimes 2-nerved, second 1-nerved, floral 

 glume 3-nerved (b) 



b. Ligule 2 mm. long, ^mpty glumes 0.5-1.7 mm. long, 

 floral glume 3.5 mm. long 3 



b. Ligule 5-7 mm. long, empty glumes 1.2 mm. long, floral 

 glume 4.4 mm. long 4 



C. Second glume usually 2-S-nervcd, floral glume 3-ncrved. . (c) 



c. Ligule 1 mm. long, empty glumes 1.5 mm. long, floral 

 glume 1.5 mm. long 5 



