Classification
Class
Magnoliopsida Brongn.
Order
Ranunculales Juss. ex Bercht. & J.Presl
Family
Ranunculaceae
Genus
Ranunculus L.
 Nomenclature
Scientific Name:
Ranunculus amphitrichus Colenso, Trans. & Proc. New Zealand Inst. 17: 237 (1884 [1885]) – as amphitricha
Synonymy:
  • = Ranunculus rivularis Banks & Solander ex DC., Syst. Nat. [Candolle] 1, 270 (1817) nom. illeg.
Vernacular Name(s):
Waoriki; Water buttercup
 Description

Perennial; rosettes tufted along creeping stems; nodes not usually bulbous. Basal lvs with slender erect or ascending petioles (2)–5–10–(15) cm long; lamina ternate, glabrous, ± circular, 1–2 cm diam.; leaflets sessile, obtriangular, bluntly 3-fid up to 1/2 way, sometimes again bluntly toothed, ± equal. Lvs of flowering stems ternate with linear acute entire leaflets. Fls 1–4–(7) per stem, 7–12 mm diam.; pedicels glabrous. Sepals spreading, glabrous. Petals 4–5, yellow, narrowly oblong, shortly clawed; nectary single, 1–1.5 mm from petal base, with a short semilunar scale. Receptacle with a basal collar of bristles. Achenes 10–20–(30), hardly flattened, glabrous; body 1.5–2 mm long, obscurely wrinkled when ripe; beak straight or curved, 1–1.5 mm long.

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

 Biostatus
Indigenous (Non-endemic)
 Bibliography
Colenso, W. 1885 ("1884"): A description of some newly-discovered and rare indigenous plants; being a further contribution towards the making known the botany of New Zealand. Transactions and Proceedings of the New Zealand Institute 17: 237–265.
Connor, H.E. 1977: The Poisonous Plants in New Zealand. Edition 2. Government Printer, Wellington. [as Ranunculus rivularis Banks & Solander ex DC.]
de Candolle, A.P. 1817 ("1818"): Regni Vegetabilis Systema Naturale, sive ordines, genera et species plantarum secundum methodi naturalis normas digestarum et descriptarum. Vol. 1. Treuttel et Würtz, Paris.
de Lange, P.J.; Rolfe, J.R.; Barkla J.W.; Courtney, S.P.; Champion, P.D.; Perrie, L.R.; Beadel, S.N.; Ford, K.A.; Breitwieser, I.; Schönberger, I.; Hindmarsh-Walls, R.; Heenan, P.B.; Ladley, K. 2018: Conservation status of New Zealand indigenous vascular plants, 2017. New Zealand Threat Classification Series. No. 22. [Not Threatened]
de Lange, P.J.; Rolfe, J.R.; Champion, P.D.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Norton, D.A.; Hitchmough, R.A. 2013: Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington. [Not Threatened]
Garnock-Jones, P.J. 1990: Typification of Ranunculus names in New Zealand. New Zealand Journal of Botany 28: 115–123.