DESCRIPTIONS OF TRIBES AND GENERA. 97 



I. Spikelets readily falling off at maturity. 



119. Alopecurus. 

 II. Empty glumes persistent ; flowering glumes 

 usually deciduous. 



1°. Flowering glume awned from below 'the 

 bifid apex. . . . 118. Echinopogon. 

 2°. Flowering glumes awnless. 



* Flowering glume somewhat longer than 

 the empty ones. . . 115. Heleochloa. 



** Flowering glume somewhat shorter 

 than the empty ones, the latter with 



winged keels 116. Maillea. 



*** Flowering glume much shorter than 

 the wingless empty ones. 117. Phleum. 

 6. Spikelets in a delicate, simple spike. 



120. Mibora. 

 e. Spikelets in a panicle consisting of small umbel- 

 like clusters ; empty glumes none. 



121. Coleanthus. 

 Q. Spikelets in a short, narrow panicle ; empty 



glumes short 122. Phippsia. 



7). Spikelets in a loose, broad panicle, empty 

 glumes as long as the flowering glumes and 



falling off with them 129. Limnas. 



Stigmas distinctly plumose (branchlets distichous), 

 projecting from the sides of the spikelets, rarely 

 remaining enclosed within them. 

 a. Grain not covered by the flowering glume and pa- 

 lea, usually with a loosely attached pericarp which 

 opens readily at maturity. . 123. Sporobolus. 

 j3. Grain covered by the flowering glume and palea, 

 pericarp adherent. 



1°. The entire spikelets deciduous (together 

 with the whole or a part of the pedicel) at 

 maturity. The pedicel of the spikelet often 

 being distinctly articulated even at the time 

 of flowering. 



* First empty glume long-awned. 



125. Chseturus. 

 ** First and second empty glumes awned. 



126. Polypogon. 



