156 A TEXT-BOOK OF GRASSES 



D. Spikelets falling off singly or in groups 

 from a continuous rachis; the first 

 glume usually larger than the second. 



Tribe 3. Nazie^ 

 DD. Spikelets faUing off singly from the (Par. 212). 



ultimate branches of a panicle; first 

 glume smaller than the second. 



Tribe 4. Melinide^ 

 cc. Lemmas thicker than the glumes, hard- (Par. 213). 



ened Tribe 5. Panice.e 



AA. Spikelets laterally compressed; hilum hnear* (Chap. 17). 



Tribe 6. Oryze.e 



(Chap. 18). 



Semes II 



A. Culms woody Tribe 13. Bambuse^ 



AA. Culms herbaceous. (Par. 270). 



B. Spikelets in spikes or spike-like racemes. 

 c. Spikelets crowded on one side of the 



rachis Tribe 10. Chlorides 



cc. Spikelets on opposite sides of the rachis. (Chap. 22). 



Tribe 12. Horded 

 BB. Spikelets in contracted or open panicles. (Chap. 24). 



c. Spikelets with 1 perfect floret. 



D. Perfect floret with 2 sterile lemmas 



below Tribe 7. Phalaride^ 



DD. Perfect floret soHtary, no sterile lemmas (Chap. 19). 



below Tribe 8. Agrostide^ 



cc. Spikelets with 2 or more florets. (Chap. 20). 



D. Lemmas awned from the back; glumes 

 usually longer than the first lemma. 



Tribe 9. Avene^ 

 DD, Lemmas awned from the tip or awn- (Chap. 21). 



less Tribe 11. Festuce^ 



(Chap. 23). 



THE MORE IMPORTANT GENERA OF GRASSES 



197. Hackel recognizes over 300 genera of grasses, 

 and some writers, including the author, recognize many 

 more, probably 400 in all. Only a few of the more im- 

 portant genera are described in the present work, the 

 selection being based upon the size of the genus, or the 



* In Gray's "Manual" this tribe is placed in Series II (Gray, Man. ed. 7, p. 88. 

 1908). 



