1 38 



GRAMINEAE. 



Vol. I. 



2. Panicum obtusum H.B.K. Blunt Panic- 

 grass. Wire- or Range-grass. Fig. 312. 



Panicum obtusum H.B.K. Nov. Gen. 1 : 98. 1816. 



Brachiaria obtusa Nash, in Britt. Man. 77. 1901. 



Glabrous, culms erect, i°-2° tall, simple or branch- 

 ing at base, smooth. Sheaths smooth; blades 2i'-g' 

 long, i"-3" wide, usually erect, long-acuminate; 

 panicle linear, 2'-6' long; branches I'-iA' long, ap- 

 pressed; spikelets about ii" long, crowded, oval or 

 obovoid, obtuse, turgid; first scale shorter than the 

 rest, obtuse, 5-nerved; second, third and fourth 

 scales about equal, the second and third 5-nerved. 



Usually in dry soil, Missouri to Arizona and Mexico. 

 Vine Mesquite-, or Grape-vme-grass. July-Sept. 



3. Panicum verrucosum Muhl. Warty Panic- 

 grass. Fig. 313. 



Panicum verrucosum Muhl. Gram. 113. 181 7. 

 Panicum debile Ell. Bot. S. C. & Ga. 1 : 129. 1817. Not 

 Desf. 1800. 



Culms erect or decumbent, slender, generally much 

 branched at base, i°-6° long. Sheaths glabrous, much 

 shorter than the internodes ; ligule short, ciliate ; blades 

 2'-y' Jong, 1 "-4" wide, erect or ascending, glabrous, 

 rough on the margins; panicle 3'-i2' long, its lower 

 branches 2' -6' long, naked below, strict and ascending, 

 or lax and spreading, and smaller panicles sometimes 

 produced at the lower part of the culm ; spikelets about 

 1" long, elliptic, acutish; the first scale about one- 

 quarter as long as the warty second and third, the 

 fourth scale apiculate. 



Moist soil, Massachusetts to Missouri, south to Florida 

 and Texas, mostly near the coast. July-Sept. 



4. Panicum dichotomifldrum Michx 



Spreading Witch-grass. Fig. 314. 



Panicum dichotomiflorum Michx. Fl. Bor. Am. 1 : 48. 



1803. 

 Panicum geniculatum Muhl. Gram. 123. 1817. 



Culms at first erect, i°-2° tall, simple, later de- 

 cumbent and geniculate, 4°-6° long, branched at all 

 the upper nodes. Sheaths loose, glabrous, some- 

 what flattened ; ligule ciliate ; blades 6-2° long, 

 2"-io" wide, long-acuminate, scabrous on the mar- 

 gins and occasionally on the nerves ; panicle pyram- 

 idal, 4'-i6' long, lower branches 3' -6' long, at 

 length widely spreading; spikelets i"-ii" long, 

 crowded, lanceolate, acute, glabrous, sometimes 

 purplish; first scale about one-fourth as long as the 

 spikelet, enclosing its base ; second and third scales 

 about equal, acute, 5-7-nerved; fourth scale elliptic, 

 shining, shorter than or equalling the third. 



In wet soil, Maine to Nebraska, Florida, Texas and 

 California. Also in the West Indies and continental 

 tropical America. Formerly confused with P. prolif- 

 erum Lam. Sprouting Crab-grass. July-Sept. 



