graminkjE. (grass family.) 537 



* * Elpikelets imperfectly several-flowered, but only one perfect flowei, and thu intenaecHate ! 



the one or two below it, and as many above, neutral. 



17. CTENIUM. Spikelets closely imbricated on one side of the axis of a single curved spike. 



# m # Spikelets with one perfect flower below and one or more neutral ones or rudiments abore. 



18. BOUTELOUA. Lower palea 3-cleft and pointed or 3-awned at the apex. Spikes dense. 



19. GYMNOPOGON. Lower palea and the rudiment l-awned. Spikes filiform, racemed. 



20. CYNODON. Flower and the rudiment awnless. Spikes slender, digitate. 



# « * # Spikelets several-flowered ; more than one of the lower flowers perfect and fertile. 



-K Spikes digitate at the summit of the culm, dense. 



21 BACTYLO CTENIUM. Glumes compressed-keeled ; outer one awned : lower palea pointed. 



22. ELEUSINE. Glumes and palea both awnless and blunt. 



■*- 4- Spikes racemed, slender, 



23. LEFTOCHLOA. Spikelets loosely spiked. Lower palea pointless or awncd at the tip. 

 Subtribe 4. Festucinb,*. Spikelets several- (few -many-) flowered, panicled ; the upper- 

 most flower often imperfect or abortive. PalesD pointless, or the lower sometimes tipped 

 with a straight (not twisted nor deeply dorsal) awn or bristle. Stigmas projecting from 

 the side of the flower. Stamens 1-3. 



* Culms herbaceous. Spikelets with the lower flowers all perfect. 



+- Grain free from the palese. (Also free in one or two species of No. 36.) 



++ Joints of the rhachis of the spikelet at the ineerlion of each flower, or the whole rbachis, 



bearded Palese convex, not laterally compressed Glumes and palesc membranaceous. 



24. TRICUSPIS. Spikelets 3 - many-flowered Lower palea hairy-fringed on the 3 nerves, one 



or all of which project into awns or mucronate tips, mostly from notches or clefts. 



25. DUPONTIA. Spikelets 2 - 3-fiowered. Lower palea scarious, entire and awnless. 



++ -M- Rhachis of the spikelet and base of the flower not bearded. 

 % Lower palea 1-pointed, awned, or acute, the nerves when present running into the point. 



26. DIARRHENA. Glumes (short) and the rigid-pointed lower 3-nerved palea coriaceous, 



convex-boat-flhaped. Stamens 2. Pericarp cartilaginoxis, large. Panicle loosely few- 

 flowered. 



27. DAOTYLIS. Glumes (rather long) and lower palea awn-pointed, herbaceous, compressed- 



keeled. Panicle contracted in one-sided clusters. 



28. BKELERIA. Glumes (nearly as long as the spikelet) and lower palea membranaccoui, 



keeled, acute or mucronate, or rather blunt. Panicle contracted, spike-like 

 H TI Lower palea awnless and pointless, blunt (except one Glyceria), the nerves parallel. 

 u. Glumes extremely dissimilar, 1^ - 3-flowcred. 



29. EATONIA. Lower glume linear ; the upper broadly obovate and folded round the flowers, 



b. Glumes alike, but often unequal in size 

 80. MELICA. Lower palea flattish-convex, many-nerved, membranaceous at the top, hard- 

 ening on the loose grain. Fertile flowers 1-3, the upper enwrapping some deformed 

 sterile flowers 



31, GLYCERIA. Lower palea convex or rounded on the back, 5 - 7-nerved, scarious at the 



tip. Spikelets many-flowered ; the flowers commonly deciduous at maturity by tha 

 breaking up of the rhachis into joints. 



32. BRIZOPYRCM. Lower palea laterally compressed and often keeled, acute, rigid, rather 



coriaceous, smooth, faintly many-nerved. Spikelets flat, spiked- clustered. 

 33 POA. Lower palea laterally compressed and mostly keeled, 5-nerved, membranaceous, 



flcarious-margined, the margins or nerves below often cobwebby or pubescent : the 



upper palea not remidning after the lower falls. Spikelets flattened 

 84. BRAGROSTIS. Lower palea 3-nerved, keeled, deciduous, leaving the upper persistent on 



the rhachis. Spikelets flat 



■*- ■*- Grain adherent to the upper palea 

 85 BRIZA. Lower palea rounded and very obtuse, pointless, many-nerved, flattened parallel 



to the glumes, becoming ventricose, broaidly scarious-margiued. Spikelets compressed, 



somewhat heart-shaped 

 SB FESTUCA, Lower palea convex on the back, acute, pointed, or awned at the tip, few- 



uerv«i- Spikelets terete or flattish. Styles terminal. 



