43 



Tribe VI.— ORYZEJE. 



Spikelets usually much compressed laterally, 1 -flowered, stam- 

 inate, pistillate, or hermaphrodite; empty glumes 2 or none, the 

 flower being subtended by the floral glume and palea alone, the 

 latter 1 -nerved and regarded by some as a second glume; stamens 

 frequently 6; axis of the inflorescence not articulated. 



A small tribe of about forty species divided among 

 sixteen genera, mostly confined to tropical America. 

 One of the best known and most extensively used of 

 the cereals, rice {Qryza sativa), belongs here. 



KEY TO THE GENERA OF THE ORYZE,E. 



1 . Spikelets unisexual, plants monoecious 2 



1. Spikelets hermaphrodite, strongly compressed 6 



2. Inflorescence of terminal and axillary spikes, the former pedun- 



culate and staminate, the latter sessile and pistillate. 



29. Hydrochloa 



2. Inflorescence paniculate 3 



3. Spikelets in pairs, the pistillate large and sessile, the staminate 



small and pedicellate 30. Pharus 



3. Spikelets not in pairs 4 



4. Staminate and pistillate spikelets in separate panicles or in the 



same panicle when the staminate are terminal. . 31. Luziola 



4. Staminate and pistillate spikelets in the same panicle, the pis- 



tillate above, the staminate below 5 



5. Fruiting spikelets narrow, subterete, caryopsis linear. 



33. Zizania 



5. Fruiting spikelets subcompressed, caryopsis ovate. 



32. Zizaniopsis 



6. Empty glumes two, flowering glume often awned.. 34. Oryza 

 6. Empty glumes none, flowering glume awnless. 



35. HoMALOCENCHRUS 



