GRAMINE^E 717 



1-3 imperfect ones. 



39 Distichlis Flowers dioecicus: flowering glumes much compressed 

 laterally, many-nerved, somewhat coriaceous. 



*+ +t +* Glumes 1-3-nerved. 



40 Catabrosa Glumes membranous, erose-truncate. 



41 GSraphephornm Rachella hirsute with stiff hairs, extended into a 

 hairy appendage : flowering glumes membranous. 



42 Panicularia Spikelets several-flowered deciduous, the rachella 

 breaking up into joints : flowering glumes rounded on the back, the 

 5-7 nerves not reaching the scarious mostly obtuse apex. 



43 Puccinellia Flowering glumes chartaceous, convex on the back, 

 faintly 2-nerved, the nerves not reaching the obtuse subdenticulate or 

 or mucronulate apex. 



44 Pleuropogon Flowering glumes chartaceous, several-nerved, the 

 nerves not reaching the truncate awned apex, 



45 Poa Flowering glumes laterally compressed, mostly keeled, 5-nerved, 

 membranous, the margins or nerves below with cobweby hairs or pu- 

 bescent: palet falling with the glume. 



46 Eragrostis Flowering glume 3-nerved, keeled, deciduous, leaving 

 the persistent palet. 



* * * Spikelets several-flowered : lowest flowers all perfect : grain 

 adherent to the palet. 



47 Briza Spikelets somewhat heart-shaped: flowering glumes rounded, 

 many-nerved, becoming ventricose. 



48 Festuca Spikelets flatfish : flowering glumes rounded on the back, 

 few-nerved, pointed or awned at the tip : ovary mostly smooth. 



49 Bromus Spikelets flattened : flowering glumes convex to compressed, 

 mostly awned below the tip: ovary pubescent. 



Tribe viii Hordeae Spikelets one- to several-flowered, ses- 

 sile in alternate notches on the opposite sides of a zigzag rachis, 

 either solitary or several together. 



* Spikelets single at each joint of the rachis. 



50 Scribneria Spikes slender, solitary : spikelets 1-flowered, almost em- 

 bedded in the notches of the rachis. 



51 Lolium Spikelets several-flowered, placed with the edge next to the 

 rachis: the inner glumes wanting except the terminal one. 



52 Agropyron Spikelets 3- to several-flowered, placed flatwise on the 

 rachis : both glumes present, standing right and left. 



* * Spikelets 2 or more at each joint of the rachis : glumes anterior, 

 forming a sort of involucre to the spikelet. 



•3 Hordeum Spikelets 1- to several- flowered, in three's at each joint: 

 lateral spikelets usually sterile. 



54 Elymus Spikelets 1- to several-flowered. 2-4 at each joint, all perfect 

 and similar : glumes shorter than the spikelets: flowering glumes not 

 long-awned. 



55 Sitanion Spikelets 1- to several-flowered, 2-4 at each joint, all perfect : 

 glumes very long, usually 2-parted to the base and long-awned : flow- 

 ering glumes long-awned and 2-toothed, or 3-awned. 



