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



157. Panicum urvilleanum Kunth. (Fig. 1539.) Culms solitary 

 or few in a tuft, 50 to 100 cm tall, erect from a creeping rhizome; 

 nodes densely bearded; sheaths overlapping, densely retrorse-villous ; 

 blades elongate, 4 to 7 mm wide, tapering from a flat base to a long 

 involute setaceous point, strigose or glabrous; panicle 25 to 30 cm 

 long, the slender branches ascending; spikelets 6 to 7 mm long, 

 densely silvery- or tawny-villous ; first glume clasping, from two-thirds 



Figure 1533.— Distribution of 

 Panicum rhizomatum. 



Figure 1534.— Pani- 

 cum Mans. Spikelet 

 and floret, X 10. 

 (Type.) 



Figure 1535.— Distribution of 

 Panicum hians. 



to nearly as long as the spikelet. % — Sandy deserts, Arizona and 



southern California; Argentina, Chile. 



14. Obtusa. — StoJoniferous wary perennial; ligules about 1 mm long; 



panicles narrow, the few appressed branches densely flowered; 



spikelets short-pediceled, secund, glabrous; fruit smooth and 



shining. 

 158. Panicum obtusum H. B. K. Vine-mesquite. (Fig. 1540.) 

 Tufted from a knotted crown, the stolons sometimes 2 m long or 

 more, with long internodes and geniculate, swollen, conspicuously 

 villous nodes; culms compressed, 20 to 80 cm tall; blades mostly 

 elongate, 2 to 7 mm wide, glabrous or nearly so; panicles 3 to 12 cm 



Figure 1536.— Panicum verrucosum. 

 Two views of spikelet, and floret, 

 X 10. (Type.) 



Figure 1537.— Distribution of 

 Panicum verrucosum. 



long, about 1 cm wide; spikelets 3 to 3.8 mm long, obovoid, brownish, 

 obtuse; first glume nearly as long as the spikelet. % — Sandy or 

 gravelly soil, mostly along banks of rivers, arroyos, and irrigation 

 ditches, western Missouri to Colorado, south to Texas and Arizona; 

 Mexico (fig. 1541). 



15. Hemitonia. — Aquatic or subaquatic perennial; panicles elongate, 

 very narrow; spikelets subsessile, 3- to 5-nerved, glabrous. 

 159. Panicum hemitomon Schult. Maidencane. (Fig. 1542.) 

 With extensively creeping rhizomes, often producing numerous sterile 

 shoots with overlapping sometimes densely hirsute sheaths; culms 50 

 to 150 cm tall, usually hard; sheaths of fertile culms usually glabrous; 

 blades 10 to 25 cm long, 7 to 15 mm wide, usually scabrous on the 

 upper surface and smooth beneath; panicle 15 to 30 cm long, the 



