626 GRAMINE.E. (GRASS FAMILY.) 



* * * Glume 3-nerved, the nerves (at least the mid-nerve) excurrent; spikelets few, in the 



axils of floral leaves. 



54. Munroa. Low or prostrate much-branched annual. 



* * * * Glume 3- (rarely 1-) nerved, obtuse or acute, awnless ; rhachis and flower naked. 



55. Koeleria. Panicle contracted. Spikelets 2 - 4-flowered. Glumes compressed-keeled, 



acute or mueronate. 



56. Eatonia. Panicle slender, more or less dense. Spikelets 2-flowered. Glumes very 



dissimilar, usually obtuse, the upper empty one enclosing the flowers. 



57. Eragrostis. Spikelets flattened, 2 -many-flowered. Glumes acute or acutish. Palet 



persistent. 



***** Glume 3 - 5-nerved, obtuse or abrupt-cuspidate ; spikelet 3 - 5-flowered ; upper 

 sterile flowers convolute around each other. 



58. Melica. Glumes 5-nerved or more, scarious, obtuse. Panicle simple or nearly so. 



59. Diarrbena. Glumes 3-nerved, coriaceous, the flowering one abruptly cuspidate. Pan- 



icle loosely few-flowered. 

 ****** Flowering glume 5-nerved or more (sometimes obscurely so). Only the ter 



minal flower abortive, or none, 

 i- Glumes more or less strongly compressed and carinate (ventricose in n. 63). 



60. Uniola. Spikelets broad, flat and 2-edged, in usually loose panicles. Glumes coria- 



ceous, acute, the 3-6 lower ones empty. 



61. DistichUs. Dioecious. Spikelets large, flattened, in a close panicle. Empty glumes 



2, acute. 



62. Dactylis. Panicle contracted in 1-sided clusters. Glumes herbaceous, awn-pointed, 



rough-ciliate on the keel. 



63. Briza. Spikelets heart-shaped, in lax panicles. Glumes roundish, ventricose, scarious- 



rnargined. 



M. Poa. Spikelets small, flattened, ovate to lance-ovate, in a loose panicle. Flowering 

 glumes membranous and scarious-niargined, pointless, usually webby or pubescent 

 toward the base. 



65. Graphepborum. Spikelets compressed, in a loose panicle, the hairy jointed rhachis 



produced into a hairy pedicel. Glumes thin-membranous, faintly nerved, entire. 



*- -i- Glumes convex on the back, not carinate (or somewhat so in n. 7U)- 



66. Scoloe.bloa. Spikelets subterete, in a lax panicle, the rhachis villous at the base of 



the flowers, ending in a naked pedicel. Glumes coriaceous, prominently 7-uerved, 

 toothed at the apex. In water. 



67. Glyceriii, Spikelets terete or flattish. Flowering glumes scarious at the usually blunt 



summit, prominently 5-7-nerved. 



68. Puccinellia. Mainly as Glyceria, but the glumes obsoletely 5-nerved. 



69. Festuca. Spikelets terete or flattish. Flowering glume acute, pointed or awned at the 



tip, few-nerved. Styles terminal. 



70. Bromns. Glume rounded or keeled on the back, mostly awued below the 2-cleft tip, 



5 -9-neived. Styles scarcely terminal. 



Tribe X. HORDE .33. Spikelets 1 -several-flowered, sessile on opposite sides of a zig- 

 zag jointed channelled rhachis, forming a spike. Empty glumes sometimes abortive or 

 wanting. Uppermost flower imperfect or abortive. 



* Spikelets single at each joint of the solitary spike. 



71. L.olium. Spikelets many-flowered, placed edgewise on the rhachis of the spike, with 



one empty glume. 



72. Agropyrum. Spikelets 3 -several-flowered, placed flatwise on the rhachis. Empty 



gliiMies 2, right and left. 



73. Lepturns. Spikelets small, 1 -2-flowered ; empty glumes 1 or 2. Spike very slender. 



* * Spikelets 2 or more at each joint of the solitary spike ; the empty glumes side by side in 



front of the spikelets (none or rudimentary in n. 76.) 



74. Hordeum. Spikelets 1-flowered, 3 at each joint, the lateral ones usually sterile. 



