Ranunculus ophioglossifolius Vill.

Erect or ascending annual to c. 50 cm high, glabrous or with few appressed hairs; roots fibrous, often produced from lower nodes. Leaves mostly cauline, the lower ones with petioles to c. 12 cm long; lamina ovate or suborbicular, to c. 40 mm long, 20 mm wide, sometimes cordate at base; upper leaves shortly petiolate, narrowly elliptic, to 65 mm long, 10 mm wide, the uppermost smaller, ± sessile; all entire or obscurely callous-toothed. Flowers few-many, in cymes, leaf-opposed. Sepals 4 or 5, spreading or slightly recurved, ovate to obovate, 2–4 mm long, with appressed hairs beneath. Petals obovate-cuneate, 2.5–4.5 mm long, pale yellow; nectary near petal-base, with lobe broad, triangular or retuse, c. 0.2 mm long, free. Stamens c. 6–10. Pistils 20–50. Receptacle glabrous. Achenes flattened-ovoid, 1.5–2 mm long, obscurely bordered; faces granular to tuberculate; beak ± triangular, 0.5–1 mm long.

Grows in swamps and other drainage areas.