II" 



GRAMINEAE. 



9. Panicum longifolium Torr. Long-leaved Panicum. (Fig. 251.) 



Panicum longifolium Torr. Fl. U. S. 149- l82 4- 



Culms erect, i-2 tall, slender, simple, or occa- 

 sionally with a single lateral panicle, flattened, 

 smooth and glabrous. Sheaths smooth and glab- 

 rous ; leaves 8'-i2' long, i // -2 // wide, acuminate 

 into a long, slender point, rough, glabrous ; 

 ligule short, pilose ; panicles 5 '-9' long ; primary 

 branches long and slender, spreading, secondary 

 very short, appressed, generally bearing 1-3 spike- 

 lets ; spikelets \" long, acuminate; first scale acute 

 about one-half as long as the acuminate second 

 one ; third scale equalling the second, acuminate, 

 one-third longer than the elliptic obtuse fourth one. 



This seems to be a well-marked species. Its slender 

 simple very much flattened culms, the long and nar- 

 row leaves, and the long slender branches of the pan- 

 icle bearing the spikelets almost racemosely, abund- 

 antly distinguish it from any others of this group. 

 Moist soil, New Jersey and Pennsylvania. Aug. -Sept. 



10. Panicum sphaerocarpon Ell. Round-fruited Panicum. (Fig. 252.) 



Panicum sphaerocarpon Ell. Bot. S. C. & Ga. i: 125. 



1817. 



Culms generally erect, simple or somewhat 

 branched at base, io / -2 tall, smooth, or the nodes 

 sometimes pubescent. Sheaths usually shorter 

 than the internodes, glabrous, the margins ciliate ; 

 leaves 2 / -4 / long, 2 // -7 // wide, acuminate, cordate- 

 clasping at base, scabrous above, smooth beneath, 

 the margins cartilaginous and minutely serrulate, 

 ciliate towards the base; panicle ovoid, 2 / ~4 / long ; 

 spikelets less than \" long, nearly spherical or 

 somewhat longer than thick, obtuse, purple ; 

 first scale broadly ovate, obtuse; third and fourth 

 scales three to four times as long as the first, subor- 

 bicular, y-nerved; fourth scale oval, obtuse, %" 

 long;"palet of third scale usually empty. 



Dry soil, southern Ontario, New York and Mis- 

 souri, to Florida, Texas and Mexico. July-Sept. 



11. Panicum microcarpon Muhl. Small-fruited Panicum. (Fig. 253.) 



Panicum i>inn>,<irf>on Muhl. Gram. in. 1817. 



Culms generally erect, 2-3 tall, simple, smooth. 

 Sheaths smooth, glabrous, longer than the inter- 

 nodes; ligule none ; leaves s'-8' long, >'-i'wide, 

 long-acuminate, smooth, cordate-clasping and spar- 

 ingly ciliate at the base ; panicle 3'-8" long, ovoid 

 to oblong in outline ; branches slender, ascending ; 

 spikelets X" long, obovoid to nearly spherical, 

 numerous; first scale minute, second and third 

 about equal, 7-ncrvcd, puberulent, the fourth 

 white and shining; palet of third scale usually 

 empty. 



-Is am] along tlik-kcts, southern New York to 

 Pennsylvania and Michigan, south to Florida, Louisi- 

 ana, Nebraska and Trxa-. July Sept. 



