Annual; stems weak and slender, 2-8 dm, sometimes reclining, sometimes rooting at the lower nodes and even becoming colonial, much branched at least distally; lvs petioled, the basal cordate to cuneate, the principal cauline ones linear-elliptic to lanceolate, 5-15 mm wide, obtuse, entire or sparsely dentate; pet 5.5-9 mm, much exceeding the sep; stamens ca 25; achenes 0.7-1.1 mm, minutely pitted, very minutely beaked. Marshes and muddy ground on the coastal plain; s. Del. to Tex., n. in the interior to s. Ill. and Ind. May, June. (R. laxicaulis; R. subcordatus; R. oblongifolius, misapplied)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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