HITCHCOCK AND CHASE—GRASSES OF THE WEST INDIES. 3805 
Rachis 2 to 2.5 mm. wide; culms mostly decumbent at 
base; spikelets abruptly minutely pointed. 
Spikelets glabrous, about 2.5 mm. long. 
9. P. denticulatum., 
Spikelets pubescent, 3 to 3.2 mm. long. 
8. P. pubiflorum. 
Rachis less than 1 mm. wide. 
Blades firm, more or less involute-margined, narrower 
at the base than the summit of the sheath. 
Culms 0.5 to 1 meter tall, not geniculate; blades 
elongate; spikelets pubescent (rarely glabrous). 
35. P. glabrum. 
Culms 20 to 40 cm. long, spreading, geniculate below; 
blades not cver 10 cm, long; spikelets glabrous. 
36. P. bakeri. 
Blades thin, flat, mostly more or less ciliate, broader 
at the base than the summit of the sheath. 
Spikelets glabrous; blades linear, scarcely 4 mm. 
wide, firm; culms stiffly erect from a short 
knotty rhizome ___________ 37. P. rigidifolium. 
Spikelets minutely pubescent (exceptionally glab- 
rous) ; blades lanceolate. 
Blades short-pubescent and pilose on the upper 
surface __-40. P. debile. 
Blades glabrous on the surface or exceptionally 
with a few hairs. 
Spikelets ovate to suborbicular; blades lax. 
39. P. ciliatifolium. 
Spikelets obovate; blades somewhat stiff. 
38. P. propinquum. 
Spikelets not over 1.8 mm. long, usually less. 
Plants annual, tufted, pilose; blades linear. 
Spikelets orbicular or nearly so, at least some of them 
sprinkled with globular hairs______ 45. P. multicaule. 
Spikelets elliptic, glabrous___________ 46. P. parviflorum. 
Plants perennial. 
Culms creeping or decumbent and rooting at the nodes. 
Spikelets pubescent ____.49. P. reptatum. 
Spikelets glabrous. 
Blades appressed-pubescent, commonly 8 to 10 cm. 
long; spikelets 1.8 mm. long______ 42. P. nutans. 
Blades glabrous; spikelets 1.4 mm. or less long. 
Racemes solitary, 1 to 1.2 em. long____31. P. breve. 
Racemes 2 or 3, 2 to 3 cm, long; spikelets minute, 
yellowish_____-__________- 48. P. orbiculatum. 
Culms tufted, not creeping nor decumbent. 
Racemes 2 to 10. 
Nodes appressed-pubescent; spikelets usually solitary. 
29. P. poiretii. 
Nodes glabrous; spikelets in pairs. 
Spikelets about 13 mm. long, obovate, blunt, 
crowded, glandular-pubescent. 
34. P. simpsoni. 
