236 POACE.E. 



c. Ligule 3 mm. long, empty glumes 1.5-2 mm. long, floral 



glume 3 mm. loug 6- 



c. Ligule 5-10 mm. long, empty glumes variable, floral 



glume 3.5 mm. long T 



c. Ligule 10-12 mm. loug, empty glumes 4-G mm. long, 



floral glume 4 mm. loug 8 



c. Ligule 10-18 mm. long, empty glumes 3.5-4 mm. long, 



floral glume 5-5.5 mm. long & 



c. Ligule 3-5 mm. long, empty glumes 1.5-3 mm. long, 



floral glume 3 mm. loug 7 



D. Floi'al glume 5-nerved, 2 mm. Jong (m) 



m. Ligule very short, floral glume 2 mm. long. ... 10 

 m. Ligule 5-7 mm. long, floral glume 12 mm. long. . .11 



E. Floral glume 3-nerved and othenvise unlike those above. . (e) 

 e. Floral glume 2 mm. or less in length (f) 



f. Floral glume about 1.5 mm. long, ligule a ring, 

 perennial 12 



f. Floral glume about 1.5 mm. long, ligule 0.5 mm. 

 long, perennial 13 



f. Floral glume 1.7-2 mm. long, ligule a ring, peren- 

 nial 14 



f. Floral glume 2 mm. long, ligule 2-3 mm. long, per- 

 ennial 15 



f. Floral glume 2 mm. long, ligule 5-6 mm. long, per- 

 ennial 16 



f. Floral glume 1.5 mm. long, ligule a ring, annual. . 17 



f. Floral glume 1.5 mm. long, ligule 1 mm. long, an- 

 nual 18 



f. Floral glume 1.5-2 mm. long, ligule 1.5-2 mm. long, 



annual 19 



e. Floral glume usually more than 2 mm. long and less 

 than 3 mm. long (g) 



g. Floral glume 2.2-2.5 mm. long, ligule 2-3 mm. 

 long, awn 10-20 mm. long 20 



g. Floral glume 2.7 mm. long, ligule 1 mm. long, awn 

 3-6 mm. long 21 



