162 Paniceae Panicum 



8. BICKNELLIANA 



Perennial ; culms few to several in a tuft ; ligules usually nearly obsolete 

 (rarely up to 1 mm long) ; blades elongated, stiffly ascending or spreading ; 

 3-8 (10) mm wide, 7-15 cm long; panicles few-flowered; spikelets on long 

 pedicels, 2.3-3 mm long, 7-nerved; autumnal form sparingly branching 

 from the upper and middle nodes. 



15. Panicum Bicknellii Nash. Map 288. Occasional plants have been 

 found on dry, wooded slopes in a few of the southern counties. 



Conn, and Mich., southw. to Ga. and Mo. 



9. DICHOTOMA 



Glabrous as a whole or nearly so, or the nodes and rarely the lower 

 sheaths and blades pubescent; ligule minute; spikelets 1.5-2.5 mm long, 

 5-7-nerved; autumnal phase freely branching. 



Nodes bearded (at least the lower ones). 



Spikelets 1.5-1.6 mm long 16. P. microcarpon. 



Spikelets more than 1.6 mm long. 



Spikelets 2 (2.2) mm long; blades rarely more than 8 mm wide 



17. P. dichotomum. 



Spikelets 2.3-2.7 mm long; blades 8-12 mm wide 18. P. mattamuskeetense. 



Nodes not bearded (glabrous or puberulent, rarely with a few long hairs). 

 Spikelets pubescent. 



Culms erect, never trailing. 



Nodes glabrous (rarely a few with hairs) ; margins of upper sheaths glabrous; 



blades mostly 6-14 mm wide; spikelets 2-2.2 mm long 19. P. boreale. 



Nodes puberulent or somewhat bearded; margins of upper sheaths pubescent 

 (rarely entirely glabrous). 



Blades 3-8 mm wide; spikelets 2 (2.2) mm long 17. P. dichotomum. 



Blades mostly 8-12 mm wide; spikelets 2.3-2.7 mm long 



18. P. mattamuskeetense. 



Culms weak, soon becoming decumbent and trailing 20. P. lucidum. 



Spikelets glabrous. 

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

 margins glabrous; spikelets more than 2.2 mm long (mostly 2.3-2.5 mm 



long) 21. P. yadkinense. 



Sheaths not marked with white spots, the margins pubescent; spikelets mostly 

 2-2.1 mm long. 



Plants of dry ground; culms erect (rarely autumnal plants reclining) 



17. P. dichotomum. 



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

 20. P. lucidum . 



16. Panicum microcarpon Muhl. Map 289. Rather frequent in the 

 southern third of the state. It seems to prefer a slightly acid soil and is 

 usually found in low, flat woods with sweet gum, pin oak, and beech, al- 

 though it is sometimes found in drier situations with different associates. 

 The Tryon specimen from La Porte County lacks the white spots on the 

 sheaths. 



The report of this species from Marshall County is evidently an error 

 in determination ; its habitat is not in that area, and the detailed descrip- 

 tion given by the collector does not apply to this species. 



Mass. to 111., southw. to Fla. and e. Tex. 



