Hydrolea uniflora Raf.

Stems decumbent or creeping at base, 3–8 dm; upper part of the stem, infl, sep, and both sides of the lvs glabrous to very minutely puberulent, the hairs not over 0.1 mm; lvs lanceolate, acuminate at both ends, 4–10 cm; cymes 1–10-fld, dense, subsessile in the axils of foliage lvs; sep lanceolate to ovate, 5–8 × 1.5–4 mm; cor 7–11 mm; styles and stamens ca 3.5–5 mm; fr glabrous, 5 mm thick; 2n=20. Wooded swamps; s. Ind. and se. Mo. to Ala. and Tex. June–Sept. (H. affinis; Nama a.)