664 



mf\ 





MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



culms; blades 3 to 6 cm. long, 3 to 5 

 mm. wide, usually glabrous on the 

 upper surface, appressed-puberulent 

 or glabrous beneath; panicle 2 to 4 

 cm. long; spikelets 1.5 to 1.6 mm. 

 long. Autumnal culms branching from 

 the middle and upper nodes, becom- 

 ing widely spreading or decumbent at 

 base. % — Sandy woods and open 

 ground, Maine to North Carolina; 

 Indiana and Michigan. 



Panicum columbianum var. thin- 

 ium Hitchc. and Chase. Vernal culms 

 more slender, usually about 20 cm. 

 tall; blades rarely more than 3 cm. 

 long, sparsely pilose with long hairs 

 on the upper surface; panicle 1.5 to 

 4 cm. long; spikelets 1.3 to 1.4 mm. 

 long. Autumnal culms with branches 

 crowded and aggregate toward the 

 summit. % — Dry sand, Massa- 

 chusetts to North Carolina; Ten- 

 nessee. 



Figure 979. — Panicum tsugetorum. Two views of 

 spikelet, and floret, X 10. (Type.) 



70. Panicum tsugetorum Nash. 

 (Fig. 979.) Vernal phase usually pale 

 bluish green; culms 30 to 50 cm. tall, 

 spreading or ascending, the lower 

 nodes often geniculate, densely ap- 

 pressecl-pubescent with short crisp 

 hairs, long hairs more or less inter- 

 mixed; sheaths pubescent like the 

 culm; ligule 1 to 1.5 mm. long; blades 

 4 to 7 mm. wide, glabrous or nearly 

 so on the upper surface, appressed- 

 pubescent beneath; panicle 3 to 7 cm. 

 long; spikelets 1.8 to 1.9 mm. long. 

 Autumnal culms decumbent-spread- 

 ing, branching from the lower and 

 middle nodes. % — Sandy woods, 

 Maine to Wisconsin, south to Georgia 

 and Tennessee. 



Figttre 980. — Panicum columbianum. Plant, X 1 ; two 

 views of spikelet, and floret, X 10. (Type.) 



71. Panicum columbianum Scribn. 

 (Fig. 980.) Vernal culms 15 to 50 cm. 

 tall, ascending, densely crisp-puber- 

 ulent ; sheaths less pubescent than the 



Figure 981. — Panicum oricola. Two views of spikelet, 

 and floret, X 10. (Type.) 



72. Panicum oncola Hitchc. and 

 Chase. (Fig. 981.) Vernal phase gray- 

 ish, often purplish; culms and sheaths 

 appressed-pilose, the culms 10 to 30 

 cm. tall, spreading; ligule 1 to 1.5 

 mm. long; blades 2 to 5 cm. long, 2 to 

 4 mm. wide, the upper surface pilose 

 with hairs 3 to 5 mm. long, the lower 

 surface appressed-pilose ; panicle 

 short-exserted, ovoid, 1.8 to 3 cm. 

 long, rather densely flowered; spike- 

 lets 1.5 mm. long, broadly obovate, 

 turgid. Autumnal culms prostrate, 

 forming mats, with short fascicled 

 branches at all the nodes. % — 

 Sand barrens along the coast, Massa- 

 chusetts to Virginia. 



10. Sphaerocarpa. — Glabrous as a 

 whole; culms few in a tuft, rela- 

 tively stout; ligules obsolete or 

 nearly so; blades mostly thick, 

 firm, cartilaginous-margined, cor- 



