GEAMINEAE. 27 



Fifth scale enclosing a perfect flower ; palet 1-nerved. 



V. Phalarideae. 

 Third scale enclosing a perfect flower; palet 2-nerved. 



VI. Agrostidcae. 

 Spikelets with 2 or more perfect flowers (or one stamiuate in 

 Nos. 35 and 40). 

 Flowering scales generally shorter than the empty lower 

 ones, usually with a bent awn on the back. 



VII. Aveneae. 

 Flowering scales generally longer than the empty lower 

 ones, unawned or with a straight awn from the apex. 



IX. Festuceae. 

 Spikelets in two rows, forming a one-sided spike or raceme. 



VIII. Chlorideae. 

 Spikelets in two opposite rows, forming an equilateral spike. 



X. Hordeae. 

 (Julms woody, at least at the base; tall reeds. XL Bambuseae. 



Tribe I. MAYDEAE. 



Tribe II. ANDEOPOGONEAE. 



1. Tripsacum. 



Spikelets alike, perfect. 2. Eriantlius. 



Spikelets not alike, the sessile perfect ; the pedicelled staminate empty or 

 wanting. 

 Inflorescence of spike-like silky racemes. 3. Andropogon. 



Inflorescence paniculate. 



Pedicelled spikelet present and usually staminate. 



4. SorgMim. 

 Pedicelled spikelet wanting. 5. Sorgliastrum. 



Tribe III. PANICEAE. 



Spikelets without subtending involucre of bristles or valves. 

 Spikelets all alike. 



Spikelets arranged in one-sided racemes. 



Eacemes alternate or scattered, rarely in a terminal pair, or 

 sometimes single and slender; in the latter case the 

 spikelets broadly oval and obtuse. 

 Spikelets of 3 scales. 6. Paspalum. 



Spikelets of 4 scales. 



Spikelets awnless, the scales glabrous. 



9. Brachiaria. 

 Spikelets with the second and third scales hispid on 

 the nerves and usually long-awned. 



10. Echinochloa. 

 Eacemes long and slender, digitate or whorled, sometimes 



single or in pairs; spikelets lanceolate and acute. 



8. Syntherisma. 

 Spikelets arranged in a true panicle, either open or contracted. 



11. Panicum. 

 Spikelets of two kinds, one borne on terminal panicles, the other soli- 

 tary on subterranean peduncles and maturing seed. 



7. Amphicarpon. 

 Spikelets subtended by an involucre consisting of : 



1-many persistent bristles; spikelets in dense spikes or spike-like pani- 

 cles, deciduous. 12. Chaetochloa. 

 Two spine-bearing valves forming a bur enclosing the spikelets and de- 

 ciduous with them. 13. Cenchnis. 



