604 GRAMINE.E. (GRASS FAMILY.) 



* * * * STIPES. Paleae coriaceous, or indurated in fruit, commonly shorter than the mem- 

 branaceous glumes, usually on a rigid base or callus ; the lower involute, terete, closely 

 enclosing the upper and the grain, mostly 1 -3-awned at the apex. Inflorescence racemose 

 or panicled : spikelets usually large, the flower deciduous from the persistent glumes, 



14. Oryzopsis. Awn simple, straight, deciduous from the palet or sometimes wanting. 



15. Stipa. Awn simple, twisted below. Callus conspicuous, pointed at the base. 



16. Aristida. Awn .triple. Upper palet small. Callus conspicuous, pointed at the base. 

 ***** Palets coriaceous or cartilaginous, awnless. Here the following would be sought by 



the student who overlooked the pair of rudimentary flowers in No. 56, and was not ac- 

 quainted with the recondite theoretical structure of No. 57 and 58. 



56. Phalaris. Spikelets laterally flattened. A rudiment at the base of each palet. 



57. Miliuiu. Spikelets dorsally flattish, not jointed with the pedicels : flowers all alike. 



68. Amphicarpum. Spikelets of two sorts, the fertile subterranean, those of the panicle 



separating by a joint without ripening grain. 



Subtribe 3. Chloridese. Spikelets rarely 1-flowered, usually 2 -several-flowered, with 

 one or more of the upper flowers imperfect, disposed in one-sided spikes ! Glumes persist- 

 ent, the upper one looking outward. Rhachis (axis) jointless. Spikes usually several and 

 racemed or digitate. Stamens 2 or 3. 



* Spikelets strictly 1-flowered. 



69. Paspalum might be looked for here, having to all appearance merely 1-flowered spikelets. 



17. Spartina. Spikelets much flattened contrary to the glumes, imbricated in 2 ranks on 



the triangular rhachis of the straight spike. 



* * Spikelets with one perfect and two or more imperfect or neutral flowers : . 

 t- The perfect flower intermediate. 



18. Ctenium. Spikelets closely imbricated on one side of the axis of a single curved spike. 



<-- The perfect flower below the one or more neutral or rudimentary ones. 



19. Bouteloua. Lower palet 3-cleft and pointed or 3-awned at the apex. Spikes dense. 



20. Gymnopogou. Lower palet and the rudiment 1-awned. Spikes filiform, racemed. 



21. Cy notion. Flower and the rudiment awnless. Spikes slender, digitate. 



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

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



22. Dactyl octenium. Glumes compressed-keeled ; outer one awned : lower palet pointed. 



23. Eleusiue. Glumes and palets both awnless and blunt. 



i- -t- Spikes racemed, slender. 



24. Leptochloa. Spikelets loosely spiked. Lower palet pointless or awned at the tip. 



Subtribe 4. Festuciiiece. Spikelets several- (few -many-) flowered, panicled; the 

 uppermost flower often imperfect or abortive. Palets pointless, or the lower sometimes 

 tipped with a straight (not twisted nor deeply dorsal) awn or bristle. Stamens 1-3. Culms 

 sometimes reed-like, but not woody. 



* Lowest flowers of the spikelet perfect and fertile. 



i- Grain free from the palets. 



H- Joints of the rhachis of the spikelet at the insertion of each flower, or the whole rhachis, 

 bearded, flumes and convex palets membranaceous. 



25. Tricuspls. Spikelets 3 - many -flowered. Lower paleae hairy -fringed on the 3 nerves, 



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



26. Grapb.epb.orum. Spikelets 2 - few-flowered. Glumes and palets awnless or pointless. 



H. -H- Rhachis of the spikelet and base of the flower not bearded. 

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



27. Dtarrhena. Glumes (short) and the rigid-pointed lower 3-nerved palet coriaceous, 



convex-boat-shaped. Stamens 2. Pericarp cartilaginous, large. Panicle loosely 

 few-flowered. 



