64 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE, 
[PLatE 19.] 
Ig. Polygonum Pennsylvanicum Linnaeus. 
Polygonum Pennsylvanicum Linnaeus, Sp. Pl. 362 (1755); Gmelin, Syst. Nat. 2: 
638; Walter, Fl. Car. 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. 8. 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; Meisner, Monog. 69, in DC. Prodr. 14: 120; Wood, Cl. Bk. Ed. 41, 474, Am. Bot. 
& Fl. 283; Chapman, Fl. 8. States, 388; Darby, Bot. 8. States, 489; S. Watson, Bot. 
Calif. 2: 13; Coulter, Man. Bot. Rocky Mt. Reg. 319. 
Annual, glabrous below, pubescent and glandular about the inflorescence and upper 
branches. Stems erect, 5-9 dm. high, simple or much branched throughout; leaves 
varying from narrowly to broadly lanceolate, 4-22 cm. long, .4—5 em. broad, acumi- 
nate and somewhat unsymmetrical at the base, glabrous or the upper ones occasion- 
ally glandular beneath, ciliate, the midrib prominent on the lower side; petioles 
about 1 em. long; ocreae cylindric or funnelform, 1-1.5 em. 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 em. long, erect, 
dense; ocreolae funnelform, 3 mm. long, oblique, wide at the summit; pedicels 3-4 
mi. 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, 5-3.5 mm. long, mostly orbicular or broader than high, short-pointed, 
black, smooth and shining. 
Noya Scotia to Florida, west to Minnesota, Nebraska and Kansas; also about Apam, 
Mexico, probably introduced. 
