44 5IEM0IRS FEOM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 



[Plate 9]. 

 g. Polygonum emersum (Michaux) Britton. 

 Polygonum ampliihium var. emersum Michaux, Fl. Bor. Am. 1 : 240 (1803). 

 Polygonum coccineum var. terrestre Pursh, Fl. Am. Sept. 271 (1814); Beck, Bot. 301. 



Polygonum amphibium var. 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. Muhlenhergii 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). 



Polygomim 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 cm. long, 1-6 cm. broad, acute or acuminate at the 

 apex, rounded, cordate, narrowed or truncate at the base, lateral nerves prominent and 

 often forking; ocreae cylindric, 2-3 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 fu unciform, oblique, 2 mm. long, fringed Avith 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, 3 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. 



