PIjANTS OF SOUTHERN NEW JERSEY. 193 



nn. Spikelets 2-2.1 mm. long. 



P. c. addisoni, p. 205 



mm. Spikelets not over 1.3-1.4 



mm. long, nearly globular. 



P. columbianum thinium, p. 207 



kk. Sheaths glabrous or pubescent only. 



/. Spikelets globular. 1.8 mm. long, 



blades cordate, ciliate at the base. 



m. Panicle as broad as long. 



P. sphccrocarpon, p. 207 

 mm. Panicle narrow, more than ^ 

 as broad as long. 



P. polyanthes, p. 208 

 //. Spikelets not globular. 



m. Culms prostrate and vine- 

 like, branches divaricate, 

 spikelets not over 2.1 mm. 

 long. P. lucidum, p. 200 



mm. Not vine-like nor divaricate. 

 n. Spikelets 2.5-3 mm. long. 

 0. Blades rarely more 

 than ID mm. broad, 

 culms crisp puberu- 

 lent. P. ashei, p. 208 

 00. Blades usually 1.5 or 

 more in width, culms 

 glabrous. 

 P. commtitatum, p. 208 

 nn. Spikelets not over 2.3 

 mm. long. 



P. clutei, p. 201 

 nnn. Spikelets not over 1.7 

 « mm. long. 



0. Culms conspicuously 

 puberulent, spikelets 

 turgid. 

 P. columbianum, p. 206 

 00. Culms glabrous. 

 P. ensifolium, p. 207 

 cc. Basal leaves not different from those of the culm. 



d. With creeping scaly root stocks, spikelets long pedicelled, not 

 secund, in open or contracted panicle. 

 e. Panicle diffuse. 



/. Panicle open, spikelets 3.5-5 mm. long, beaked. 



P. virgatum, p. 196 



ff. Panicle more or less contracted, 3.2 mm. long, not 



beaked. P. v. cubense, p. 196 



ee. Panicle contracted, seashore species. P. amarum, p. 196 



dd. Not forming a creeping scaly rootstock. 



13 MUS 



