12 Bulletin VII. 1. 



51. Flowerino^ glumes three-nerved, rounded on the back, coria- 

 ceous, subulate pointed 49. Diarrhena. 



51. Flowering glumes three- to many-nerved, herbaceous, mem- 



branaceous, or chartaceous 52 



52. Terminal sterile florets, in each spikelet club-shaped, flow- 



ering glumes papery-membranaceous with a broad and 

 scarious apex 48. Melica. 



52. Terminal sterile florets not club-shaped 53 



53. Empty glumes nearly equal in length, but very dissimilar; 



the first narrowly linear, one-nerved; the second broadly 

 obovate, folded around the florets, three-nerved . . . 

 47. Eatonia. 



53. Empty glumes similar, but often of unequal length ... 54 



54. Spikelets crowded in one-sided clusters on spreading 



branches, flowering glumes awn-pointed and strongly 

 ciliate on the keel above 52. Dactylis. 



54. Spikelets not crowded in one-sided clusters 55 



55. Spikelets of two forms, fertile and sterile, the latter pecti- 



nate and standing with the fertile; inflorescence terminal, 

 spike-like 53. Cynosurus. 



55. Spikelets all alike 56 



56. Flowering glumes compressed, keeled, usually bearing a 



tuft of cobwebby hairs at the base, and sometimes soft 

 hairs on the more prominent nerves below . . 54. Poa. 



56. Flowering glumes rounded on the back, naked or pubescent, 



not cobwebby at base (spikelets much flattened and 

 glumes compressed in Bromus uniolotdes.) 57 



57. Styles inserted below the apex of the ovary, which has a 



hairy, cushion-like summit 57. Bromus. 



57. Styles terminal; grain smooth 58 



58. Flowering glumes awnless, nerves prominent. 55. Glyceria. 



58. Flowering glumes often awned, nerves indistinct (visible 



only near the apex) 56. Festuca. 



59. Spikelets single at each joint of the rachis 60 



59. Spikelets two or more at each joint of the rachis . . . . Gt, 



60. Spikelets placed edgewise to the rachis; empty glume (ex- 



cept in the terminal spikelet) one .... 58. Lolium. 



60, Spikelets placed with their sides against the rachis, empty 



glumes two 61 



61. Flowering glumes with a distinct callus, falling at maturity 



with the grain, which is adherent to the palea .... 

 59. Agropyrum. 



61. Flowering glumes without a distinct callus, persistent; grain 



free (>2 



62. Empty glumes subulate, one-nerved .... 60. Secale. 

 62. Empty glumes lanceolate or ovate, three to many-nerved . 



61. Triticum. 



6^. Spikelets with only one hermaphrodite flower, 62. Hordeum. 

 6t^. Spikelets with two or more hermaphrodite flowers ... 64 

 64. Emptv glumes nearly equalling the flowering glumes . . 



. .' 63. Elymus. 



64. Empty glumes, minute or none 64. Asprella. 



