Glab. branching herb up to 2 dm. or more long; stems creeping, rooting at nodes, sts floating; stock slender to stout, erect or ascending, sts moniliformly thickened. Radical lvs in tufts at nodes, on slender to filiform petioles 2-10-(15) cm. long; sheath membr., delicate. Lamina obovate-cuneate to suborbicular to reniform in outline, 0·5-4 cm. diam.; flabellately divided to base into 3-5-(7) segs; these narrow-cuneate to linear ± deeply toothed, rarely entire. Lower cauline lvs similar, smaller; upper reduced to bracts 1 cm. or less long. Peduncles lf-opposed, 4-10 cm. long; fls 5-7-(10)mm. diam., solitary or paired; sepals 5, spreading, 3-5 mm. long; petals 5-10, yellow, 3-6 mm. long, narrow-oblong; gland 1 well above base. Fruiting heads globose, ± 7 mm. diam.; receptacle glab.; achenes ± turgid, glab., 1·5-2 mm. long, keeled, obliquely obovoid; style 1·5-2 mm. long, subulate, ± recurved at apex.