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



acuminate; first glume clasping, two thirds to three fourths as long 

 as the spikelet, acuminate or cuspidate. 91 Prairies and open 

 ground, open woods, and brackish marshes, Quebec and Maine to 

 Montana, south to Florida, Nevada, and Arizona; Mexico and Cen- 

 tral America. PANICUM VIRGATUM var. CUBENSE Griseb. Culms 

 more slender, usually solitary or few in a tuft; panicle narrower with 

 ascending branches; spikelets 2.8 to 3.2 mm long, the second glume 

 and sterile lemma not extending much beyond the fruit. 91 Pine 

 woods, Coastal Plain, Massachusetts to Florida and Mississippi; 

 Michigan; Cuba. PANICUM VIRGATUM var. SPISSUM Linder. Culms 

 from short stout knotty rhizomes. 91 Nova Scotia to Penn- 

 sylvania. 



143. Panicum ha vardii Vasey. (Fig. 1513.) Pale green, glaucous, 

 glabrous throughput; culms robust, solitary, 1 m tall or more, 

 erect from creeping rhizomes; blades 5 to 10 mm wide, tapering 

 into long involute-setaceous tips; panicle as much as 40 cm long; 

 spikelets 6 to 8 mm long. 91 Arroyos and sand hills, western 

 Texas and southern New Mexico; northern Mexico. 



144. Panicum amarum Ell. (Fig. 1514.) Glaucous and glabrous 

 throughout; culms solitary from the nodes of extensively creeping 



FIGURE 1510. Distribution of 

 Panicum repens. 



FIGURE 1511. Panicum gouini. Two 

 views of spikelet, and floret, X 10. 

 (Type.) 



rhizomes, 30 to 100 cm tall; blades thick, 10 to 30 cm long, 5 to 12 

 mm wide, flat, involute toward the tip, the margins smooth; panicle 

 one-fourth to one- third the height of the plant, not more than 3 cm 

 wide, the branches appressed; spikelets 5 to 6.5 mm long, acumi- 

 nate. 9J. Sandy seashores and coast dunes, Connecticut to 

 Georgia; southern Mississippi; Texas (fig. 1515). 



145. Panicum amarulum Hitchc. and Chase. (Fig. 1516.) Culms 

 as much as 1 cm thick, in large bunches as much as 1 m across, 

 1 to 2 m tall, glaucous; rhizomes vertical or ascending; blades 20 

 to 50 cm long, 5 to 12 mm wide, more or less involute, pilose on the 

 upper surface near the base; panicle large, rather compact, 5 to 10 

 cm wide, slightly nodding, densely flowered; spikelets 4.3 to 5.5 mm 

 long, acuminate. 9J. Sandy seashores and coast dunes, New 

 Jersey to Virginia; Florida; Louisiana and Texas; Yucatan; Baha- 

 mas; Cuba (fig. 1517). 



9. Tenera. Perennials; culms subcompressed, wiry; ligules minute; 

 spikelets short-pediceled ; fruit smooth and shining. 



146. Panicum tenerum Beyr. (Fig. 1518.) Culms in small tufts 

 from a knotted crown, erect, 40 to 90 cm tall; lower sheaths pubescent 

 toward the summit with spreading hairs; blades 4 to 15 cm long, 2 

 to 4 mm wide, erect, firm, subinvolute, pilose on upper surface toward 

 base; panicles 3 to 8 cm long, very slender, terminal and axillary; 

 spikelets 2.2 to 2.8 mm long, pointed, glabrous, the pedicel usually 



