\ 
GRAMINEAE 73 
4. Inflorescence spicate. (Tribe ZOISEAB)...............0.....-.--- 17. Zoisia 
4. Inflorescence paniculate. (Tribe TRISTIGINEAE).... 18. Arundinella 
8. Flowering glume and palea very different in texture and appearance 
from the empty glumes, coriaceous or chartaceous. (Tribe 
PANICEAE. ) 
4. Spikelets all perfect. 
5. Spikelets not involucrate. 
6. Empty glumes 2. 
7. Perfect flowers 1 in each spikelet. 
8. First empty glume with a ring-like callus... 19. Eriochloa 
8. Ring-like callus wanting; spikelets in 1-sided racemes or 
spikes. 
9. Spikelets ovate or orbicular, obtuse, rarely acute. 
20. Paspalum 
9. Spikelets lanceolate or ovate-lanceolate, acute or acu- 
a eal ada oi tae ie sta ka hat ei 21. Digitaria 
7. Perfect flowers 2 in each spikelet........................ 22. Isachne 
6. Empty glumes 38. 
7. Glumes unawned; spikelets panicled or spicate. 
23. Panicum 
7. Empty glumes or flowering glumes awned or awn-pointed. 
8. Slender grasses; empty glumes smooth.... 24. Oplismenus 
8. Coarse grasses; empty glumes muricate. 
23. Panicum § Echinochloa 
5. Spikelets subtended by an involucre consisting of 1 to many 
bristles or spines which are sometimes: grown together. 
6. Involucre of 2 spine-bearing valves quite enclosing the spike- 
ne SRG EIR E ath EOS MEE Shc anes Sinclair He 25. Cenchrus 
6. Involucre of numerous bristles....................---.---.--++-+- 26. Setaria 
6. Involucre of solitary bristles. 
Tis POTS BOUSUC STAR... 5.2. ete 27. Chamaeraphis 
mgr gh = TLS ge: Lhe atic) eee bud aee aay ly Meanie nee Ree oot fl 26. Setaria 
4. Spikelets monoecious or dioecious. 
5. Monoecious; a slender, prostrate grass, the inflorescence a 
terminal spike, the 2 lower spikelets perfect, the 4 to 6 upper 
og EEL peach an aaa ie el el dnl ee fl Naa i. a 28. Thuarea 
5. Dioecious; a very coarse, spreading grass; female flowers in 
large, globose heads with very long slender spines; male 
flowers in umbellately disposed racemes................ 29. Spinifex 
2. Spikelets laterally compressed; empty glumes none or rudimentary. 
(Tribe ORYZEAE.) 
3. Empty glumes 2, short but distinct; spikelets awned or awnless. 
30. Oryza 
3. Empty glumes none; spikelets awnless.................--------------- 31. Leersia 
1. Spikelets 1- to many-flowered, the empty glumes persistent, the rachilla 
articulated above the empty glumes and produced above the upper 
glume. 
2. Stems herbaceous; leaf-blades sessile, not jointed with the sheaths. 
3. Spikelets 1-flowered; inflorescence paniculate. (Tribe AGROSTIDEAE. ) 
4, Flowering glume awnless....................-.-:---2-0se1e0e---ee0-00 32. Sporobolus 
4. Flowering glume with a slender, 3-fid awn.................. 33. Aristida 
3. Spikelets few- to many-flowered, if 1-flowered then the spikes 
digitately arranged. 
