MANUAL OF THE GRASSES OF THE UNITED STATES 



683 



branches erect, the lower distant, the upper approximate, 2 to 10 

 cm long; spikelets 2.4 to 2.7 mm long, lanceolate, acute; first glume 

 about half the length of the spikelet; fruit less rigid than usual in 

 the genus, the apex of the palea scarcely enclosed. % — Moist soil 

 along river banks and ditches, borders of lakes and ponds, often in 



Figure 1538.— Panicum brachyanihum. Two views of spikelet, and floret, X 10. (Type.) 



the water, sometimes a weed in moist cultivated fields, Coastal Plain, 



New Jersey to Florida and Texas; Brazil (fig. 1543). 



16. Gymnocarpa. — Succulent glabrous perennial; panicles of several 



to many long stiffly ascending racemes along a main axis; 



spikelets strongly 3- to 5-nerved, glabrous. 

 160. Panicum gymnocarpon Ell. (Fig. 1544.) Creeping, the base 

 as much as 2 m long, rooting at the nodes; culms 60 to 100 cm tall; 



Figure 1539.— Panicum urvilleanum. Two views of spikelet, and floret, X 10. (Type.) 



blades elongate, 15 to 25 mm wide, flat, scarcely narrowed at the 

 cordate, sparingly ciliate base, the margin very scabrous; panicle 20 

 to 40 cm long ; spikelets 6 to 7 mm long ; first glume nearly as long as 

 the sterile lemma, the second glume exceeding the sterile lemma, 

 all acuminate-pointed, much exceeding the obovate, stipitate fruit, 

 this 2 mm long, smooth and shining. % — Ditches and muddy 

 banks of streams and lakes, Georgia and Florida to Texas (fig. 1545). 



