44 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 
[Puate 9]. 
g. Polygonum emersum (Michaux) Britton. 
Polygonum amphibium var. emersum Michaux, Fl. Bor. Am. 1: 240 (1803). 
Polygonum coccineum vay. terrestre Pursh, Fl. Am. Sept. 271 (1814); Beck, Bot. 301. 
— 
Polygonum amphibium vay. terrestre Torrey, Fl. 1: 403 (1824), not Willdenow; 
Torrey, Comp. 172; Meisner, Monog. 67; Darlington, Fl. Cest. 250; A. Gray, Man. 388; 
Wood, Am. Bot. and Fl. 283. 
Polygonum amphibium var. Muhlenbergii Meisner in DC. Prodr. 14: 116 (1856). 
Polygonum Muhlenbergii S. Watson, Proc. Am. Acad. 14: 245 (1879); Bot. Calif. 
2:13; Coulter, Man. Bot. Rocky Mt. Reg. 320; Behr, Fl. San Francisco, 276; Greene, 
Fl. Francis. 137, Man. Bay Reg. Bot. 42. 
Polygonum terrestre Britton, Sterns & Poggenberg, Prel. Cat. N. Y. 46 (1888). 
Polygonum emersum Britton, Trans. N. Y. Acad. Sci. 8: 73 (1889). 
Perennial, glabrous or strigose throughout. Stem more or less creeping in wet 
places, the distal end erect, 3-8 dm. long, mostly simple, leafy, enlarged at the nodes, 
channeled, lower parts becoming hollow; leaves broadly-lanceolate or oblong-lanceolate, 
sometimes narrowly-lanceolate, 5—20 em. long, 1-6 em. broad, acute or acuminate at the 
apex, rounded, cordate, narrowed or truncate at the base, lateral nerves prominent and 
often forking; ocreae cylindric, 2-5 cm. long, the younger clasping the stem, the older 
ones loose and inflated near the base, eciliate; inflorescence consisting of one or two 
terminal spicate racemes; racemes linear-oblong or linear, 3-10 cm. long, erect, dense ; 
ocreolae funnelform, oblique, 2 mm. long, fringed with short bristles; pedicels slender, 
1-2 mm. long; calyx dark rose-colored, sometimes pink, 4 mm. long, five-parted to the 
middle; stamens five, exserted; style 2.5 mm. long, two-cleft to above the middle, 
exserted; achene lenticular, 5 mm. long, broadly-obovoid or orbicular, conspicuously 
biconvex, black, slightly granular but shining. 
Throughout North America from the Arctic regions to the City of Mexico. 
s 5 y 
