574 
CXIII. GRAMINEiE 
Lower empty glume shorter than the upper, hut 
obvious. Lower flowering glume containing a 
rudimentary or male flower or empty . . .3. Panicum. 
Spikelets scattered on hair-like, drooping branches, 
2-flowered, both flowers often fertile. Rhachilla 
jointed above the 2 equal, empty glumes . . .2. Isachne. 
Spikelets awned, but not surrounded by an involucre of bristles. 
Spikelets 1 -flowered. Empty glumes 3, nearly equal, 
the lowest long-awned. Flowering glume not awned . 4. Oplismenus. 
Spikelets 2-flowered, not jointed. Empty glumes 2, 
unequal, acute. Flowering glume awned . . .5. Arundinella. 
Spikelets awnless and surrounded by an involucre of bristles. 
Spikelets in spikes or in a cylindric, tapering panicle ; 
stalks bearing an involucre of long bristles and not 
jointed at the base ....... 6. Setaria. 
Spikelets in a dense raceme ; stalks bearing an involucre 
of long, sometimes fringed bristles and jointed at 
the base . . . . . . . . .7. Pennisetum. 
Tribe II. Zoysiese. Spikelets in a slender raceme, 1 -flowered, 
very narrow, falling off with their stalks. Empty glumes 2, long- 
awned 8. Perotis. 
Tribe III. Andropogonese. Spikelets in spikes or panicles, 
rarely in racemes, 1 -flowered (except in Ischcemum and the sessile 
spikelets of Pogonatherum, Apluda and Rottboellia), hairy, rarely 
glabrous, usually in pairs, one sessile, the other stalked, alike 
or dissimilar, sometimes in threes, one sessile, two stalked, 
rarely solitary. Empty glumes 2 or 3, of firmer texture and longer 
than the flowering glumes. Flowering glumes small, very thin, 
usually bifid, with a long awn. 
Spikelets in simple spikes. Spikes clustered, rarely solitary. 
Spikelets in pairs, both alike. 
Spikes not jointed, very many. Spikelets 1 -flowered, 
partially enveloped in a tuft of long, yellow hairs . 
Spikes jointed, soon breaking up, 2-10. Spikelets 1- 
flowered, nearly glabrous or more or less enveloped 
in brown or white hairs ..... 
Spikes one to several. Spikelets 2-flowered, each 
with a tuft of short hairs at its base . 
Spikes several, rarely only one, thick, cylindric, 
jointed. Spikelets 2-flowered, sometimes dis- 
similar, adpressed against or partially sunk in the 
rhachis ........ 
Spikelets in pairs, dissimilar (see also Rottboellia). 
Spikes solitary, slender. Sessile spikelet 2-flowered ; 
stalked spikelet 1 -flowered ..... 
Spikes digitately or umbellately clustered or in pairs, 
rarely solitary, sheathed in a spathe-like bract 
Spikelets solitary, sessile, usually accompanied by the 
stalk of a second abortive spikelet. Spikes 2 or 
more, clustered ...... 
1 Species 1, 2 and 8-14. 
9* Miscanthus. 
11. Pollinia. 
14. Ischcemum. 
18. Rottboellia . 
15. Pogonatherum * 
19. Andropogon. 1 
16. Arthraxon. 
