ANDROPOGONE^. 41 



sessile, the branches and branchlets more or less included by a 

 broad spathe or sheath having little or no blade. 



A. Pedicellate spikelets with 1-2 glumes half as long as the 

 sessile ones, culms simple below, much branched above. 



a. Spikes 4-6-jointed (h) 



b. Spikes 1-2 cm. long, sessile spikelets 4 mm. long 11 

 b. Spikes 2-7 cm. long, sessile spikelets 5 mm. long 12 



Spikelets 6 mm. long ..(c) 



c. Spikes 3-4 cm. long 13 



c. Spikes 5-7 cm. long 14 



a. Spikes 10-20-jointed . . . (d) 



d. Spikes 2 cm. long, mostly raised above the tips 



of the long bracts 15 



d. Spikes mostly with bracts as long as them- 

 selves (e) 



e. Spikes about 2 cm. long, sessile spikelets 



3-5 mm. long (f\ 



f. Plant slender, spikes in remote clusters 16 

 f. Plant stout, spikes mostly clustered near 



the top 17 



e. Spikes 2-3 cm. long, sessile spikelets 3 mm. 



long. Some plants of 19 



e. Spikes 2-3 cm. long, sessile spikelets 4 mm. 

 long 18-20 



B. Pedicellate spikelets staminate, with 4-5 glumes, as long as 

 the sessile ones, which are 7-11 mm. long, branching little 

 above. 



a. Spikes 2, near or at the apex of the culm or its 



branches 21, 22 



a. Spikes 3-8, digitate near the apex of the culm. . . 23 



Subgenus 4. Amphilophis. Spikes digitate or panicled at the 



apex of the culm or branches, all pedicellate. Joints of the rachis 



and the pedicels with a median, longitudinal, translucent line. 



Floral glume tapering into an awn. 



a. Pedicellate and sessile spikelets equal 24 



a. Pedicellate spikelets shorter than the sessile, spikes in a ter- 

 minal panicle often branched .25 



