142 THE TRUE GRASSES. 



<3 <1 Only the lowest flower $ , 

 the others $ , remote. 



238. Zeugites. 

 ft Leaves linear or lanceolate, no 

 distinct transverse veins. 

 O Keel of the palea winged or 

 with a linear appendage. 



243. Pleuropogon. 

 O O Keel of the palea not ap- 

 pendaged. 



<\ Empty glumes 3-6 at the 

 base of each spikelet. 

 . X Spikelets one-flowered. 

 244. Brylkinia. 

 XX Spikelets many-flow- 

 ered. . . 245. Uniola. 

 O < Empty glumes tAvo. 



X Plants strictly dioe- 

 cious ; spikelets almost 

 sessile. 246. Distichlis. 

 XX Plants hermaphrodite 

 (very rarely dioecious, 

 and then loosely pani- 

 culate). 



□ Flowering glumes 



cordate at the base. 



247. Briza. 



D □ Flowering glumes 



not cordate at the 



base. . . AA, etc. 



AA. Spikelets closely imbricate, arranged in a linear, dense, 



false spike. 



aa. Flowering glumes lanceolate, indistinctly five- 

 nerved 249. Wangenheimia. 



bb. Flowering glumes broadly ovate-lanceolate, 

 seven-nerved with glandular hairs at the base. 



248. Desmazeria. 

 Note. — Compare Festuca and Brachypodium, whose spike- 

 lets stand farther apart and whose glumes are not keeled. 



BB. Spikelets densely imbricate, crowded in short spikes, 



