DESCRIPTIONS OF TRIBES AND GENERA. 35 



y. Flowering glume and palea membranaceous, 

 empty glumes, herbaceous or chartaceous ; the 

 first empty glume smaller or narrower than the 

 following ones. Spikelets falling oft' singly 

 from the ultimate branches of the panicle. 



IV. Tristeginese. 



S. Flowering glume and palea cartilaginous, 

 coriaceous, or chartaceous. Empty glume more 

 delicate, usually herbaceous, the first usually 

 smaller. Spikelets falling off singly from the 

 ultimate branches of the panicle or continuous 

 (rarely articulate) rachis of a spike. 



V. Panicese. 

 b. Hilum linear, spikelets laterally compressed. 



VI. Oryzese. 

 B. Spikelets 1-co flowered, the 1-fl owe red frequently with the 



rachilla produced beyond the flowers, rachilla generally 

 articulated above the empty glumes, so that these remain 

 after the fall of the fruiting glumes. When from two- to 

 many-flowered there always are distinct internodes be- 

 tween the flowers. 



a. Culm herbaceous, annual ; leaf-blade sessile, not 

 articulated with the sheath. 



a. Spikelets upon distinct (sometimes very short) 

 pedicels, in panicles, spike-like panicles, or 

 racemes (without notches in the main axis). 

 I. Spikelets one-flowered : 



1. Empty glumes four, palea one-nerved. 



VII. Phalaridese. 



2. Empty glumes two (rarely none), palea 

 two-nerved. . . . VIII. Agrostidese. 



II. Spikelets 2-co flowered : 



1. Flowering glume generally shorter than 

 the empty ones ; usually with a bent 

 awn on the back, rarely awned from the 

 point or awnless. When not awned 

 there are two nearly opposite florets, 

 and the rachilla is not produced beyond 

 them IX. Aveneae. 



2. Floral glume generally longer than the 



