6 MISC. PUBLICATION 243, U. S. DEPT. OF AGRICULTURE 
Spikelets perfect (rarely unisexual but then not as above), usually artic- 
ulate above the glumes. 
Spikelets articulate below the glumes, 1-flowered, very flat, the lemma 
and palea about equal, both keeled. Glumes small or wanting. 
9. ORYZEAE (p. 9). 
Spikelets articulate above the glumes (rarely below, but the glumes, at 
least one, well developed). 
Spikelets, 1-flowered (or the staminate 2-fiowered), in groups (short 
spikes) of 2 to 5 (single in Zoysia), the groups racemose along a 
main axis, falling entire; lemma and palea thinner than the 
glumes 402758. eA eh ee en eae 6. ZOYSIEAE (p. 8). 
Spikelets not as above. 
Spikelets sessile on a usually continuous rachis (short-pedicellate 
in Leptochloa; the rachis disarticulating in Hordeum). 
Spikelets on opposite sides of the rachis; spike terminal}, solitary. 
3. HOoRDEAE (p. 8). 
Spikelets on one side of the rachis; spikes usually more than one, 
digitate or racemose..........._-_:*_- 7. CHLORIDEAE (p. 9). 
Spikelets pediceled in open or contracted, sometimes spikelike, 
panicles, rarely racemes. « 
Spikelets 1-flowered......-..........---._--- 5. AGROSTIDEAE (p. 8). 
Spikelets 2- to many-flowered. 
Glumes as long as the lowest floret, usually as long as the 
spikelet (sometimes shorter in Sphenopholis); lemmas 
awned from the back (awnless in Sphenopholis). 
4. AVENEAE (p. 8). 
Glumes shorter than the first floret....2. WFESTUCEAE (p. 7). 
SUBFAMILY 2. PANICOIDEAE 
Spikelets with one perfect terminal floret (disregarding those of 
the few monoecious genera and the staminate and neuter spikelets) 
and a sterile or staminate floret below, usually represented by a 
sterile lemma only, one glume sometimes (rarely both glumes) want- 
ing; articulation below the spikelets, either in the pedicel, in the 
rachis, or at the base of a cluster of spikelets, the spikelets falling 
entire, singly, in groups, or together with joints of the rachis; 
spikelets, or at least the fruits, more or less dorsally compressed. 
Key to the Tribes of Panicoideae 
Glumes membranaceous, the sterile lemma like the glumes in texture. 
Fertile lemma and palea scarcely firmer than the glumes. 
11. MBELINIDEAE (p. 155). 
Fertile lemma and palea indurate or at least firmer than the glumes. 
12. PANicEA® (p. 161). 
Glumes indurate; fertile lemma and palea, hyaline or membranaceous, the sterile 
lemma like the fertile one in texture. 
Spikelets unisexual, the pistillate below, the staminate above, in the same 
inflorescence or in separate inflorescences______- 14. TRIPSACEAE (p. 423). 
Spikelets in pairs, one sessile and perfect, the other pediceled and usually 
staminate or neuter (the pediceled one sometimes obsolete, rarely both 
pediceled) 22:52 S552 os en eee aes 13. ANDROPOGONEAE (p. 376). 
DESCRIPTIONS OF THE TRIBES AND KEYS TO THE GENERA 
TRIBE 1. BAMBUSEAE 
Culms woody, perennial, usually hollow; spikelets, 2- to several- 
flowered, in panicles or racemes, or in close heads or fascicles; often 
1 or more sterile lemmas at base of spikelet; lemmas usually awnless; 
blades usually articulated with the sheath. 
Culms climbing or clambering. 
Spikelets 2- to several-flowered, racemose_____-_ 3. ARTHROSTYLIDIUM (p. 15). 
Spikelets 1-flowered, in small panicles________.______- 4. CHUSQUEA (p. 22). 
