GBAMINEAE (GRASS FAMILY) 41 



Tribe Vm. CHLORIDEAE 



Spikelets with perfect flowers, 

 Spikelets deciduous as a whole, the articulation below the glumes. 

 Spikelets much flattened; glumes imequal, keeled . . • 40. Beckmanida. 

 Spikelets subterete; glumes equal, convex .... 37. Spartina. 

 Spikelets in part persistent, the articulation above some of the 

 glumes. 



Spikes few (1-4) 38. Bouteloua. 



Spikes numerous. 

 Spikes long, very slender; plant annual . . . .34. Schedonnardus. 



Spikes short, one-sided 39. Atheropogon. 



Spikelets with imperfect flowers, the pistillate very different from the 



staminate and on very short culma 41. Buchloe. 



Tribe IS. FESTUCACEAE 



Lemma 3-lobed and 3-awned 42. Scleropogon. 



Lemma entire or 2-lobed. 



Rachilla long-hirsute 44. Phragmites. 



Rachilla glabrous or with short haira. 



Plant prostrate, with spinescent leavw 43. Munioa. 



Plants erect, leaves not spinescent. 

 Lemma 3-nerved (or rarely 1). 

 Lateral nerves hairy. 

 Inflorescence a congested raceme; leaves with cartilagi- 

 nous margins 45. Tricuspis. 



Inflorescence a panicle; leaves not cartilaginous on the 



margins 47. Diplachne. 



Lateral nerves glabrous. 



Lemma long-hirsute at basa . . ... . . 46. Redfieldia. 



Lemma glabrous at base. 

 Glumes similar. 



Inflorescence spike-like BO. Eoeleria. 



Inflorescence an open panicle. 

 Rachilla continuous; flowering glumes decidu- 

 ous, the palet persistent .... 48. Eragrostis. 

 Rachilla articulated; flowering glume and palet 



both deciduous 51. Catabrosa. 



Glumes very dissimilar 49. Estonia. 



Lemma 5-nerved or more. 

 Spikelets with the upper florets sterile and folded about 



each other 62, Melica. 



Spikelets with the upper floret perfect, or narrow and 

 abortive 

 Stigmas arising below the apex of the ovary . . .60. Bromus. 

 Stigmas arising at the apex of the ovary. 

 Lemma compressed and keeled. 

 Awn-pointed ....... 64. Dactylis. 



Pointless. 



Glumes 1-3-nerved. 

 Scarious-margined ..... 66. Poa. 



Membranous ....... 66. Graphephorum. 



Glumes 5-nerved or more ..... 53. Distichlis. 



Lemma convex or rounded on the back. 



Acute or awned 69. Festuca. 



Obtuse and scarious at apex. 



Prominently 5-7-nerved 87. Clyceria. 



Obscurely fi-nerved .68. Puccinellia. 



Tribe X. HORDEAE 



Spikelets mostly solitary at each joint of the rachis. 



Spikelets placed edgewise on the rachis 61. LoHum. 



