Plants annual, 2-15 dm; roots also often arising from proximal nodes. Stems scandent, ribbed, glabrous; prickles 0.5-1 mm. Leaves: ocrea tan or brownish, cylindric, 8-15 mm, chartaceous, base inflated or not, with prickles, margins oblique, ciliate with bristles 0.5-2.5 mm, surface glabrous or appressed- to spreading-pubescent; petiole 1-7 cm; blade broadly hastate to hastate-cordate or triangular, (2-)6.5-13(-18) × (1-)6-11(-16) cm, base truncate to truncate-cordate, margins broadly hastate with lobes divergent, ciliate, sometimes also retrorsely prickly, apex acuminate, faces appressed-pubescent or, rarely, glabrous adaxially, stellate-pubescent or, rarely, glabrous abaxially, major veins often bearing prickles. Inflorescences capitate or paniclelike, uninterrupted, 5-12 × 3-8 mm; peduncle 10-80 mm, retrorsely prickly proximally, stellate-pubescent and stipitate-glandular distally, glands red or pink; ocreolae usually overlapping, sometimes not overlapping proximally, margins eciliate or ciliate with bristles to 0.5 mm. Pedicels mostly ascending, 2-3 mm. Flowers 2-4 per ocreate fascicle; perianth pink or red, often whitish green proximally, glabrous, accrescent, not becoming blue and fleshy in fruit; tepals 4, connate 3- 2 their length, broadly elliptic, 5-6 mm, apex acute to obtuse; stamens (6-)8, filaments distinct, free; anthers pink, elliptic; styles 2, distinct. Achenes included, dark brown to black, biconvex, 3.5-6 × 3-4 mm, shiny, smooth. Flowering Jul-Oct. Shaded swamps, ponds, tidal marshes along rivers, wet ravines in forests; 0-600 m; N.B., N.S., Ont., P.E.I., Que.; Conn., Del., D.C., Ga., Ill., Ind., Ky., La., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., Wash., W.Va., Wis.
From Flora of Indiana (1940) by Charles C. Deam
Infrequent to rare in springy and swampy places throughout the state. This species is much visited by honey bees.
Much like no. 30 [Polygonum sagittatum L.]; lvs hastate, to 20 נ15 cm, finely stellate beneath, the basal lobes triangular, divergent; peduncles commonly glandular above; perianth 2.5 mm, pink; styles 2, 0.5 mm; achene lenticular, 3.5-5 mm. Marshes, swamps, and wet meadows; N.B. to Minn., s. to Ga. and Mo. Aug-Sept. (Tracaulon a.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.