T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Ranunculus acaulis (Sand buttercup)

Kingdom: Plantae
Division: Embryophyta
Class: Angiosperms
Order: Ranunculales
Family: Ranunculaceae
Genus: Ranunculus
Species: R. acaulis
Binomial name: Ranunculus acaulis
Common names: Sand buttercup, Dune Buttercup, Shore buttercup

Ranunculus acaulis is an indigenous low-growing perennial, succulent buttercup that forms tight clumps. The dark bronze greens to dark green leaves are stalked and arise from the base of the plant. They are thick and shining, and are divided into 3 deep blunt lobes: the median one is entire or 3-toothed, while the lateral ones are entire or unequally divided. The plant spreads by white underground stems in coastal sands.
The bright yellow flowers which occur during August – April are 7–10 mm in diameter and are solitary on stems that are scarcely as long as the leaves. Each flower has 5–8 narrow greenish-yellow petals about 5 mm long, and a dense cluster of stamens. The fruit (September - July ) consists of 5–10 achenes.
It occurs in the three main islands, the Chatham and the Auckland Islands in coastal dampish sands throughout, and also grows on the shores of Rotorua, Tarawera and Taupo. It found in Australia (Tasmania), South America (Chile) and the Falkland Islands. A specimen of Ranunculus acaulis is housed in Te Papa Collections, collected 26 Dec 1963 from the coastal cliffs of Patea Beach, South Taranaki. In South Taranaki the coastal buttercups Ranunculus repens and R. acaulis are under threat from Chilean rhubarb (Gunnera tinctoria). In DOC Annual report of 2003 it mentions that assailers were brought in to tackle the gunnera on 40 km of South Taranaki coastal cliffs where the plant is replacing the native plant species.

For more information, visit:  http://nzpcn.org.nz/flora_details.asp?ID=2236 

Photographed at OtariNativeBotanic Garden and Wilton's Bush Reserve. Wellington.