HITCHCOCK AND CHASE GRASSES OF THE WEST INDIES. 347 



Bristles solitary, below only part of the spikelets ; branches of the panicle 

 elongate ; blades broad, usually more than 1 cm. wide, plaited, tapering 

 at each end. (Section Ptychophyi.lum. ) 

 Plants annual ; blades 1 to 8 cm. wide ; main panicle branches rather dis- 

 tant, 1 to 3 cm. long 1. C. barbata. 



Plants perennial ; blades 3 to 8 cm. wide ; main panicle branches ap- 

 proximate, mostly over 3 cm. long. 

 Panicle dense, long and narrow, the branches ascending; sheaths gla- 

 brous or mostly so 3. C. sulcata. 



Panicle loose, the branches spreading or drooping, the lower 10 to 15 



cm. long; sheaths hirsute 3. C. palmifolia. 



Bristles 1 or more below each spikelet (or below only a part of the spikelets 

 in C. setosa). 

 Plants annual. 



Bristles antrorsely scabrous. 



Bristles 5 to 12 at the base of each spikelet; second glume half as 



long as the rugose fruit 11. C. lutescens. 



Bristles 1 to 3 at the base of each spikelet ; second glume about as 

 long as the spikelet. 

 Plants robust ; spike 15 to 30 mm. thick ; fruit smooth. 



12. C. magna. 

 Plants slender, rarely X meter tall ; spike scarcely 1 cm. thick ; 



fruit slightly roughened 13. C. viridis. 



Bristles, or some of them, retrorsely scabrous. 



Plants 1 meter or more tall ; bristles mostly more than 1 cm. long, 



divaricate and implicate 15. C. tenacissima. 



Plants low (rarely 70 cm. high), often spreading; bristles usually 

 not over 5 mm. long, straight or nearly so. 

 Ilachis villous ; bristles several below each spikelet. 



16. C. scandens. 

 Rachis not villous ; bristles 1 or 2 below each spikelet. 



14. C. verticillata. 

 Plants perennial. 



Inflorescence a dense cylindrical spike. 



Nodes and sheaths glabrous 9. C. geniculata. 



Nodes appressed-pubescent ; sheaths scabrous and sparsely hispid. 



10. C. hispida. 

 Inflorescence more or less open or Interrupted, or tapering, not a dense 

 cylindrical spike. 

 Blades commonly 3 cm. wide, tapering into a long petiole-like base. 



8. C. vulpiseta. 



Blades mostly less than 2 cm. wide, not tapering into a petiole-like 



base. 



Spikelets at maturity globose, about as thick as long ; bristles, 



or some of them, 2 cm. long or more. 



Sheaths densely long-villous on the collar; blades about 



2 cm. wide 7. C. impressa. 



Sheaths slightly pilose on the collar ; blades about 1 cm. 



wide 6. C. onurus. 



Spikelets ovoid, longer than thick; bristles mostly less than 1 

 cm. long. 

 Blades slender, mostly less than 5 mm. broad; spike slen- 

 der, very narrow 5. C. rariflora. 



