156 A TEXT-BOOK OF GRASSES 
p. Spikelets falling off singly or in groups 
from a continuous rachis; the first 
glume usually larger than the second. 
Tribe 3. NazIezx 
DD. Spikelets falling off singly from the (Par. 212). 
ultimate branches of a panicle; first 
glume smaller than the second. 
Tribe 4. MELINIDEX 
cc. Lemmas thicker than the a hard- (Par. 213). 
CMERS otcct crete pense cabs Tribe 5. PANICEZ 
AA. Spikelets laterally compressed; hilum linear* (Chap. 17). 
Tribe 6. OryzE= 
(Chap. 18). 
A AEE WONG. Usacvi sss boc eee ees Tribe 13. BAMBUSE= 
AA. Culms herbaceous. (Par. 270). 
B. Spikelets in spikes or spike-like racemes. 
c. Spikelets crowded on one side of the 
PRO so oes Soe ee Tribe 10. CHLORIDEZ 
cc. Spikelets on opposite sides of the rachis. (Chap. 22). 
Tribe 12. HorDEx 
BB. Spikelets in contracted or open panicles. (Chap. 24). 
c. Spikelets with 1 perfect floret. 
p. Perfect floret with 2 sterile lemmas 
EAE. eens Tribe 7. PHALARIDEX 
pp. Perfect floret solitary, no sterile lemmas (Chap. 19). 
below....... .Tribe 8. AGROSTIDEX 
cc. Spikelets with 2 or more florets. (Chap. 20). 
Dp. Lemmas awned from the back; glumes 
usually longer than the first lemma. 
Tribe 9. AVENEX 
pp. Lemmas awned from the tip or awn- (Chap. 21). 
BIR Aor oe ee id oe ere. 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 
ey In Gray’s “‘Manual” this tribe is placed in Series II (Gray, Man. ed. 7, p. 88. 
