GRAMINEAE 73 



4. Inflorescence spicate. ( Tribe Zoiseae ) 17. Zoisia tH 



4. Inflorescence paniculate. ( Tribe TristigineaeK ... 18. Arundinella gr 

 3. Flowering glume and palea very different in texture and appearance 

 from the empty glumes, coriaceous or chartaceous. ( Tribe 

 Faniceae. ) 

 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 riftg-like callus.... 19. Eriochloa gs^ 

 8. Ring-like callus wanting; spikelets in 1-sided racemes or 

 spikes. 

 9. Spikelets ovate or orbicular, obtuse, rarely acute. 



20. Paspalum . sc 

 9. Spikelets lanceolate or ovate-lanceolate, acute or acu- 

 minate 21. Digitaria P? 



7. Perfect flowers 2 in each spikelet 22. Isachne /f 



(J. Empty glumes 3. 



7. Glumes unawned; spikelets panicled or spicate. 



23. Panicum 91 

 7. Empty glumes or flowering glumes awned or awn-pointed. 

 8. Slender grasses; empty glumes smooth.... 24. Oplismenvs It- 

 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- 

 lets , 25. Cenchrus ?S" 



6. Involucre of numerous bristles 26. Setaria tS" 



6. Involucre of solitary bristles. 



7. A floating aquatic grass 27. Chamaeraphis <ft 



7. A terrestrial grass 26. Setaria <f*r 



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 



ones male... ;..- 28. Thuarea 1<> 



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. Sjiinifex I7 



i. Spikelets laterally compressed; empty glumes none or rudimentary. 

 ( Tribe Oryzeae. ) 

 3. Empty glumes 2, short but distinct; spikelets awned or awnless. 



30. Oryza ft 



3. Empty glumes none; spikelets awnless 31. Leersia i( 



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 32. Sporobohis 18 



4. Flowering glume with a slender, 3-fid,awn 33. Arislida i«) 



3. Spikelets few- to many-flowered, if 1-flpwered then the spikes 

 digitately arranged. 



