POLYGONACEOUS GENERA. 47 



beneath and the margins with some scattered bristly hairs; 

 foliage widely spreading. 



Eiparian state ? (provisionally P. Nebrascensis). Leaves as- 

 cending, more remote, distinctly short-petioled, the internodes 

 twice the length of the sheaths, the rim of the latter quite 

 narrow ; peduncle of the short oblong spike with a few delicate 

 gland-tipped hairs, bracts thinly somewhat hirsute-hairy. 



The terrestrial type is known to me only as collected by my- 

 self on the open prairie at Prairie Junction in southeastern 

 Minnesota, 7 July, 1898. It is exceedingly well marked in habit 

 and foliage, much resembling some alternate-leaved asclepiads. 

 The riparian plant, very likely distinct, is typified in Mr. Eyd- 

 bergs' n. 1649 from central Nebraska, as in U. S. Herb. 



P. AMMOPHiLA. Terrestrial, and even of rather dry sandy 

 soil. Decumbent stems a foot or two long in fertile plants and 

 loosely leafy, lower, with short internodes and a dense leafiness 

 in the sterile state : leaves lanceolate, 3 to 5 inches long, acute, 

 only the uppermost with midvein hirsute beneath, this in the 

 lowest quite glabrous and the leaf -surface scarcely roughened 

 with scattered hair-points, ocrese with very thin villous sheath 

 and broad toothed and bristly-ciliate border : spikes mostly 2, 

 oblong, their peduncles beset with a few short gland-tipped hairs 

 and fewer long bristly ones; bracts hirsute-ciliate, otherwise 

 nearly glabrous : achenes small, somewhat obovate, black and 

 shining. 



The fertile type of this has been sent me Jby Mr. Holzinger 

 from Winona, Minn., where he collects it on high sandy banks 

 of the Mississippi. Sterile specimens were taken by myself on 

 dry sandy banks of the same river, at LaOrosse, Wis., 8 July, 

 1898. 



P. MUBicuLATA. Stout, decumbcut, the somewhat branching 

 stems 2 feet long, densely leafy, with a foliage at length widely 

 spreading, the internodes barely an inch long and nodes swollen: 

 leaves elliptic-lanceolate, 4 or 5 inches long including the short 

 stout petiole, merely acutish at both ends, sparsely scabrous and 

 strigose above, marginally short-ciliate with appressed setose 



