Ranunculus trichophyllus Chaix

Aquatic perennial, rarely terrestrial; roots all fibrous. Rhizome creeping. Stems slender to stout, prostrate or ascending, up to 1–(2) m long. Lvs divided into many filiform segments, glabrous but for a few short hairs at segment tips, (1)–3–6–(8) cm long; segments narrowly linear in terrestrial plants; petiole (2)–5–30 mm long. Fls solitary, 8–15 mm diam. Pedicels terete, glabrous, (2)–3–6–(8) cm long. Sepals 5, bluish near tip, reflexed, 2.5–4 mm long. Petals 5, white with yellow base, 6–8 × c. 4 mm long; nectary single, 0.5–1 mm from petal base, lunate. Receptacle usually with a few sparse hairs at base, elongating slightly at fruiting. Achenes 30–60, glabrous, ovoid, slightly flattened, transversely rugose; body 1.5–2 mm long; beak straight, c. 0.5 mm long.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

Flowering: (Oct.)–Dec.–Feb.–(Apr.); Fruiting: (Oct.)–Dec.–Feb.–(Apr.)