18 POACEAE. 



Spikelets with at least the empty glumes persistent. 



Glumes above the perfect flower none ; spikes digitate, very slender. 



39. SCHEDONARDUS. 



Glumes above the perfect flower i -several ; spikes scattered. 



Spikes 1-4, rarely more ; spikelets 25 or more. 40. BOUTELOUA. 



Spikes numerous, 12 or more; spikelets few, less than 12. 



41. ATHEROPOGON. 



Spikelets with 2-3 perfect flowers ; spikelets alternate. 42. LEPTOCHLOA. 



Spikelets dioecious ; those of the two sexes very unlike. 43. BULBILIS. 



TRIBE 9- FESTUCEAE. 



Flowering glumes, at least of the pistillate spikelets, 3-lobed and 3-awned ; plant 



dioecious. 44. SCLEROPOGON. 



Flowering glumes entire or at most 2-lobed. 



Hairs on the rachilla or flowering glume very long and enclosing the latter. 



45. PHRAGMITES. 



Hairs, if any, on the rachilla and the flowering glume shorter than the glume. 

 Stigmas barbellate on elongated styles ; spikelets in threes in the axils of 



spinescent leaves. 46. MUNROA. 



Stigmas plumose, sessile or on short styles. 

 Flowering glumes i-3-nerved. 



Lateral nerves of the flowering glumes hairy. 

 Flowering glumes deeply 2-lobed. 



Internodes of the rachilla long, often half as long as the flowering 



glume ; plants without stolons. 47. TKIPLASIS. 



Internodes of the rachilla short, many times shorter than the glumes ; 



plants with long, arching stolons. 48. DASYOCHLOA. 



Flowering glume entire or slightly 2-lobed ; internodes of the rachilla 



short. 



Inflorescence a short congested raceme ; leaf-blades with thick car- 

 tilaginous margins. 49. ERIONEURON. 

 Inflorescence a panicle ; leaf-blades not with cartilaginous margins. 

 Panicle simple or compound ; the spikelets on pedicels of varying 



length. 50. TRIDENS. 



Panicles composed of long branches, along which the appressed 



spikelets are arranged on short pedicels. 51. DIPLACHLE. 

 Lateral nerves of the flowering glumes glabrous. 



Callus of the flowering glumes copiously pubescent with long hairs ; 



panicle open. 52. REDFIELDIA. 



Callus of the flowering glumes glabrous. 



Second empty glume similar to the first or nearly so. 



Panicle narrow, dense and spike-like, shining; its branches erect. 



53. KOELERIA. 



Panicle open ; its branches spreading. 



Rachilla continuous (except in E. major) ; flowering glume de- 

 ciduous ; palet persistent ; plants of dry soil. 



54. ERAGROSTIS. 

 Rachilla articulated ; flowering glumes and palet both deciduous 



with the rachilla-internodes ; water plants with 2-flowered 

 spikelets. 55. CATABROSA. 



Second empty glume very unlike the first one, broad at the summit. 



56. EATONIA. 

 Flowering glumes s-many-nerved. 



Spikelets with two or more of the upper glumes empty, broad and enfold- 

 ing each other. 57. MELICA. 

 Spikelets with upper glumes flower-bearing or narrow and abortive. 

 Stigmas placed at or near the apex of the ovary. 



Spikelets borne in one-sided fascicles which are arranged in a glom- 

 erate or interrupted panicle ; flowering glumes herbaceous. 



58. DACTYLIS. 



