Stems reclining, trailing, or decumbent (sometimes rooting at nodes), simple or branched, 3-10.5 dm, glabrous or sparsely stipitate-glandular; rhizomes ± slender; bulblets absent. Leaves opposite; petiole 0.5-4 cm, ciliate proximally, cilia 0.2-0.9 mm; blade lanceolate to ovate-lanceolate, 2-10 × 0.5-3 cm, base rounded or obtuse to cuneate, decurrent, margins entire, plane, ciliolate (or rarely finely papillate or sometimes eciliolate), apex acute to acuminate, surfaces not punctate, glabrous; venation pinnate-arcuate. Inflorescences axillary, solitary flowers (rarely leafy racemes). Pedicels 1-3 cm, glabrous. Flowers: sepals 5, calyx sparsely or not streaked with resin canals, 2-5 mm, glabrous, lobes lanceolate, margins thin; petals 5, corolla yellow with reddish base, sparsely streaked with scattered dark resin canals (sometimes obscure), rotate, 2-6 mm. lobes with margins entire or erose apically, apex apiculate, stipitate-glandular adaxially; filaments apparently distinct or connate at very base, shorter than corolla; staminodes 0.4-1 mm. Capsules 2.5-5 mm, not punctate, glabrous. 2n = 34.
Rhizome short and freely rooting; stems slender, to 1 m, laxly and diffusely branched, soon becoming prostrate or spreading and often rooting; nodes usually with a fringe of short hairs; lvs lanceolate or lance-ovate, the larger ones 4-10 נ1-2.5 cm, scabrous on the margin, broadly acute to rounded at base, on long, eciliate petioles; cal-lobes and cor-lobes 3-5 mm; stamens distinct; staminodes triangular-subulate, obtuse; fr equaling or exceeding the cal; 2n=34. Swamps and wet soil, usually in shade; e. and c. Va.; Mo. and s. Ill. to e. Tex. and w. Fla. June-Aug. (Steironema r.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.