64 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 



[Plate 19. J 

 ig. Polygonum Pennsylvanicum Linnaeus. 



Polygonum Pennsijlvanicuvi Linnaeus, Sp. PL 362 (1753); Gmelin, Syst. Nat. 2: 

 638; Walter, Fl. (^ar. 132; Willdenow, Sp. PL 448; Michaux, Fl. Bor. Am. 1: 240; 

 Persoon, Syn. 1: 440; Muhlenberg, Cat. 40 ; Pursh, FL Am. Sept. 271; Eaton, Man. 

 371; Elliott, Bot. S. C. and Ga. 1: 457; Sprengel, Syst. 2: 256; Barton, Comp. Fl. PhiL 

 187; Torrey, Fl. 1: 404, Comp. 172, Fl. N. Y. 2 : 150; Beck, Bot. 302; Darlington, 

 Florula Cest. 48, Fl. Cest. 250 ; Eaton & Wright, N. A. Bot. Ed. 8, 368 ; A. Gray, Man. 

 387; :\Ieisner, Monog. 69, in DC. Prodr. 14: 120; Wood, CI. Bk. Ed. 41, 474, Am. Bot. 

 & Fl. 283 ; Chapman, FL S. States, 388 ; Darby, Bot. S. States, 489 ; S. Watson, Bot. 

 C^alif. 2: 13; Coulter, INIan. Bot. Rocky Mt. Reg. 319. 



Annual, glabrous below, pubescent and glandular about the inflorescence and upper 

 branches. Stems erect, 3-9 dm. high, simple or much branched throughout; leaves 

 varying from narrowly to broadly lanceolate, 4-22 cm. long, .4-5 cm. broad, acumi- 

 nate and somewhat unsymmetrical at the ba,se, glabrous or the upper ones occasion- 

 ally glandular beneath, ciliate, the midrib prominent on the lower side; petioles 

 about 1 cm. long; ocreae cylindric or funnelform, 1-1.5 cm. long, rather thin, 

 glabrous, brittle and eciliate; inflorescence paniculate, more or less simple, the ulti- 

 mate divisions ending in spicate racemes ; racemes oblong-cylindric, 2-5 cm. long, erect, 

 dense; ocreolae funnelform, 3 mm. long, oblique, wide at the summit; pedicels 3-4 

 mm. long, angled; calyx pink or light purple, sometimes reddish, 3-4 mm. long, five- 

 parted to or below the middle; stamens eight or fewer, included; style 3 mm. long, 

 two-parted to about the middle, mostly included ; achene lenticular, flat or sometimes 

 slightly biconcave, 3-3.5 mm. long, mostly orbicular or broader than high, short-pointed, 

 black, smooth and shining. 



Nova Scotia to Florida, west to Minnesota, Nebraska and Kansas ; also about Apam, 

 Mexico, probably introduced. 



