Panicum Paniceae 153 



Pedicels mostly longer than the spikelets; spikelets not subsecund on the lower 

 side of the branchlets of the inflorescence. 

 Spikelets not more than 1.8 mm long. 



Nodes bearded; ligule less than 1 mm long; sheaths usually covered more 



or less with white spots 16. P. microcarpon, p. 162. 



Nodes not bearded; ligule more than 1 mm long; sheaths without white 



spots 22. P. sprettim, p. 164. 



Spikelets 1.9-2.8 mm long. 



Sheaths or some of them usually marked more or less with white spots, 

 the overlapping margin usually glabrous; spikelets more than 2.2 



mm long (mostly 2.3-2.5 mm long) 21. P. yadkinense, p. 164. 



Sheaths not marked with white spots, the overlapping margin pubescent; 

 spikelets 2-2.8 mm long. 



Spikelets 2.3-2.8 mm long 15. P. Bicknellii, p. 162. 



Spikelets 2-2.2 mm long. 



Plants of dry ground; culms erect, rarely autumnal plants reclin- 

 ing 17. P. dichotomum, p. 163. 



Plants of bogs and swamps ; culms weak, soon becoming decumbent 



and trailing 20. P. lucidum, p. 163. 



\. Spikelets pubescent. 

 Blades mostly more than 15 mm wide. 



Sheaths, at least the lower ones and those of the branches, papillose-hispid; 



spikelets 2.7-3 mm long (rarely longer) 46. P. clandestinum, p. 173. 



Sheaths not papillose-hispid. 



Nodes retrorsely bearded; spikelets 4-4.5 mm long. 



Blades glabrous or nearly so on both surfaces 48. P. Boscii, p. 174. 



Blades velvety to the touch beneath 48a. P. Boscii var. molle, p. 174. 



Nodes not retrorsely bearded, glabrous or minutely appressed-pubescent. 



Spikelets 3.2-3.7 mm long 47. P. latifolium, p. 174. 



Spikelets 2.5-3 mm long 45. P. commutatum, p. 173. 



Spikelets 1.4-1.6 mm long 39. P. polyanthes, p. 170. 



Blades mostly less than 15 mm wide. 



Blades elongated, not over 5 mm wide and more than 20 times as long as wide. 

 Spikelets beaked, mostly 3.2-3.8 mm long (rarely as short as 3 mm). 



Sheaths pilose 11 . P. depauperatum, p. 160. 



Sheaths glabrous or nearly so. .11a. P. depauperatum var. psilophylhmi, p. 160. 

 Spikelets not beaked, 3 mm or less in length (rarely 3.2 mm long). 



Spikelets 2.7-3.2 mm long; panicles narrow, usually less than a third as wide 



as long; ligules mostly about 1 mm long 12. P. perlongum, p. 161. 



Spikelets 2.2-2.7 mm long; panicles usually more than a third as wide as 

 long; ligules mostly less than 1 mm long. 



Sheaths pilose 13. P. lineari folium, p. 161. 



Sheaths glabrous or nearly so.. 13a. P. lineari folium var. Werneri, p. 161. 

 Blades not elongated or, if elongated, more than 5 mm wide. 

 Spikelets 3 mm or more long. 



Spikelets beaked, somewhat curved, smooth except the scabrous keels 



7. P. anceps, p. 159. 



Spikelets obovate, not curved, more or less pubescent with spreading hairs. 

 Ligule less than 0.5 mm long; blades papillose-hispid above and beneath; 



spikelets papillose-hispid 41. P. Leibergii, p. 171. 



Ligule more than 0.5 mm long; blades not papillose-hispid; spikelets not 

 papillose. 

 Culms and at least the lower sheaths with an appressed pubescence; 

 ligules mostly 1.5 mm long with longer hairs intermixed; spikelets 



oblong-obovate, mostly 3.5-4 mm long and 1.7-1.9 mm wide 



42. P. oligosanthes, p. 171. 



