Ranunculus amphitrichus Colenso

Variable, usually partially or entirely submerged stoloniferous perennial. Leaves with petioles 1–15 cm long; lamina trifoliolate to palmatisect, 1–5 (–7) cm diam., ± circular in outline, glabrous; segments linear-oblong when deeply submerged, cuneate to obovate when aerial, 3-toothed or 3–many-lobed. Flowering stems 1–10 cm long, erect to spreading, 1–4-flowered. Sepals 4 or 5, spreading (sometimes later ± reflexed), broadly ovate, 2–3 mm long, glabrous. Petals 4–9, oblong to narrowly obovate, 2–4 mm long, yellow to pale yellow-green; nectary a tumid semilunar pocket or bracket, c. 1/3 petal-length from base. Stamens c. 10–18. Pistils c. 6–15. Receptacle hispid in stamen zone, glabrous or with few hairs in achene zone. Achenes sublenticular, 1.5–2 mm long, somewhat swollen, smooth or slightly wrinkled or warted; beak slender, straight or slightly curved, almost as long as achene-body.

In swamps, ponds, dams, along rivulets etc., sometimes permanently submerged, mostly in shallow water, but recorded from clear water up to 8 m deep (R.Filson 15821c , MEL).