642 



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



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. Autum- 



Figure 1387. — Panicum wilmingtonense. 

 Two views of spikelet, and floret, X 10. 

 (Type.) 



Figure 1388.— PaTiicura tsugetorum. 

 Two views of spikelet, and floret, 

 X 10. (Type.) 



nal culms decumbent-spreading, branching from the lower and middle 

 nodes. % — Sandy woods, Maine to Wisconsin, south to Georgia 

 and Tennessee (fig. 1389). 



68. Panicum columbianum Scribn. (Fig. 1390.) Vernal culms 

 15 to 50 cm tall, ascending, densely crisp-puberulent; sheaths less 

 pubescent than the culms; blades 3 to 6 cm long, 3 to 5 mm wide, usu- 

 ally 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, becoming widely spreading 

 or decumbent at base. % — Sandy woods 

 and open ground, Maine to North Carolina; 

 Indiana (fig. 1391). 



Panicum columbianum var. thinium Hitchc. 



and Chase. Vernal culms more slender, usu- 

 ally 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; spike- 

 lets 1.3 to 1.4 mm long. 

 Autumnal culms with 

 branches more crowded 



and aggregate toward the summit. % — Dry 



sand, Massachusetts to Virginia. 



69. Panicum oricola Hitchc. and Chase. (Fig. 

 1392.) Vernal phase giayish, 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, Massachusetts to Virginia (fig. 1393). 



Figure 1389— Distribution of 

 Panicum tsugitorum. 



Figure 1390.— Panicum colum- 

 bianum. Plant, X 1; two views 

 of spikelet, and floret, X 10. 

 (Type.) 



