84: MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 



[Plate 29.] 

 29. Polygonum Hydropiper Linnaeus. 



Polygonum Hydropiper Linnaeus, Sp. PL 361 (1753); Gmelin, Syst. Nat. 2: 638; 

 Michaux, Fl. Bor. Am. 1 : 238 ; Persoon, Syn. 1 : 440 ; Muhlenberg, Gat. 40 ; Bigelow, 

 Fl. Bost. 93; Meisner, Monog. 76 and in DC. Prodr. 14: 109; Hooker, Fl. Bor. Am. 2: 

 132; Torrey, Fl. N. Y. 2 : 150; A. Gray, Man. 387; Wood, Am. Bot. and Fl. 283; S. 

 Watson, Bot. Calif. 2: 14; Coulter, Man. Bot. Rocky Mt. Reg. 320. 



Polygonum punctatum Torrey, FL N. Y. 2 : 151 (1834), not Elliott. 



Annual, glabrous, usually bright green. Stem erect or assurgent, 2-6 dm. long, 

 lax, simple or branched throughout, sometimes red or reddish; leaves varying from 

 ovate to oblong-lanceolate sometimes lanceolate, 1.5-9 cm. long, .3-2.3 cm. broad, acute 

 at both ends or often acuminate at the apex, ciliate, more or less papillose, undulate or 

 slightly crisped, punctate, containing a very acrid juice; ocreae cylindric, .5-1 cm. long, 

 becoming somewhat funnelform and oblique, nearly glabrous, fringed with long bristles, 

 usually enlarged about the bases, often bearing one or two flowers within ; inflorescence 

 paniculate, more or less compound, the ultimate divisions ending in spicate racemes; 

 racemes linear, 2-6 em. long, drooping, much interrupted; ocreolae funnelform, 1.5-2 

 mm. long, slightly oblique, fringed with a few short bristles ; pedicels slender, 2 mm. 

 long; calyx greenish, 2.5-3 lum. long, three to five-parted, usually four-parted, the seg- 

 ments rather narrowly oblong, obtusish, glandular; stamens four or sometimes six, in- 

 cluded; style .5 mm. long, two or three-parted to near the base; achene lenticular, bicon- 

 vex, slightly gibbous or triquetrous, 3 mm. long, broadly oblong or ovoid, sometimes 

 orbicular or even broader than high, short-pointed, dark brown, strongly granular and dull. 



Canada to Florida and westward across the continent. Naturalized from Europe 

 southward and eastward, said to l^e native in the north and west. 



