GRAMINEAE. 



Vol. I. 



56. Panicum Addisonii Nash. Low Stiff 

 Panic-grass. Fig. 366. 



P. Addisonii Nash, Bull. Torr. Club, 25 : 83. 1898. 



Culms io'-is' tall, rigid, tufted, erect or decum- 

 bent at the base, at length much branched, the 

 branches erect, pubescent below with long nearly 

 appressed hairs which decrease in length toward 

 the summit where they are very short. Sheaths 

 often longer than the internodes, appressed-pubes- 

 cent, at least the lower ones ; ligule a ring of hairs ; 

 blades erect, lanceolate, thickish, smooth and gla- 

 brous on both surfaces, rough on the margins, 

 acuminate, i'-z' long, ii"-3" wide; panicle ovate 

 to oblong, i'-2l' long, its branches spreading or 

 ascending; spikelets obovate, 1" long, the first scale 

 acute or acutish, about one-half as long as the 

 spikelet, i-nerved, pubescent, second and third scales 

 9-11-nerved, densely pubescent with spreading hairs. 



Sandy soil, Massachusetts to South Carolina. May- 

 June. 



57. Panicum Commonsianum Ashe, 

 mons' Panic-grass. Fig. 367. 



Com- 



P. C ommonsianum Ashe, Journ. E. Mitch. Sci. Soc. 

 15: 55. 1898. 



Culms tufted, i2'-2o' tall, pubescent below with 

 long nearly appressed hairs, the upper portion gla- 

 brous or puberulent, finally branched, the nodes 

 barbed with spreading hairs ; sheaths, at least the 

 lower ones, pubescent with long often appressed 

 hairs ; ligule i" long or more ; blades ii'~4' long, 

 1V-4" wide, erect, lanceolate, appressed-pubescent 

 on the lower surface with stiff hairs, the upper sur- 

 face glabrous or with some long spreading hairs 

 toward the base; panicle ii'-3' long, ovate, its 

 branches spreading or ascending; spikelets ii" to a 

 little less than 3" long and i as broad, obovoid, 

 pubescent with spreading hairs, the first scale about 

 i as long as the spikelet. 



In dry sandy soil near the coast, Connecticut to 

 North Carolina and Florida. June and July. 



58. Panicum columbianum Scribn. Amer- 

 ican Panic-grass. Fig. 368. 



Panicum columbianum Scribn. Bull. U. S. Dept. Agric. 



Div. Agrost. 7: 78. 1897. 

 P. psammophilum Nash, Bull. Torrey Club, 26 : 576. 



1899. 

 P. columbianum var. thinium Hitchc. & Chase, Rhodora, 



10: 64. 1908. 



Culms tufted, erect, softly pubescent, 8-2° tall, at 

 length dichotomously branched, the branches erect. 

 Lower sheaths pubescent, the upper glabrous, the 

 primary one-half as long as the internodes; ligule 

 a ring of short hairs ; blades lanceolate, erect, thick- 

 ish and firm, glabrous above, the lower ones more 

 or less pubescent beneath, the primary \Y-2h! long, 

 2"-3" wide, those on the branches smaller; panicle 

 small, ovate, i'-ii' long, its branches ascending; 

 spikelets broadly obovate, a little more than i" 

 long, the outer 3 scales densely pubescent with 

 spreading hairs, the first scale about one-half as 

 long as the spikelet, i-nerved, the second and third 

 scales 7-nerved. 



Fields and open woods, Maine to Virginia, Tennessee 

 and Alabama. June-Sept. 



