The New Zealand Plant Conservation Network

Species

Ranunculus macropus

Etymology

Ranunculus: From the Latin 'rana' frog, meaning little frog and probably refers to the plants typical marshy habit where frogs abound
macropus: big foot

Common Name(s)

Swamp buttercup

Current Conservation Status

2012 - Data Deficient

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Data Deficient
2004 - Gradual Decline

Authority

Ranunculus macropus Hook.f.

Family

Ranunculaceae

Flora Category

Vascular - Native

NVS Species Code

RANMAC

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

Ranunculus longipetiolatus Colenso

Distribution

Endemic to the North and northern South Islands. In the North Island formerly widespread from the northern Waikato south to Wellington. Most recent collections come from the western Waikato, Rotorua Lakes District and East Cape to Hawkes Bay. In the northern South Island, apparently always scarce, and there seem to have been no collections made over the last 20 or so years. Recently (2010) a population was found at Canadian Flats on the Taieri River in Otago.

Habitat

Coastal to lowland. Usually found in raupo (Typha orientalis) dominated wetlands where it grows in still moderately deep to deep water.

Features

Semi-aquatic to aquatic herb. Rosettes tufted on stout creeping stems. Basal leaves on very stout petioles (7-)15-30(-40) mm x 5-10 mm, arising from bulbous nodes. Leaves ternate (15-)-20-40(-80) mm wide, leaflets sessile or shortly stalked, cuneiform, shallowly 3-fid, apices crenate, serrate or entire, lateral leaflets slightly to distinctly larger than terminal, caulien leaves few, similar to basal but smaller. Flowers (1-)3-5 per stem, 10-15(-20) mm diam., pedicels galbrous. Sepals speading or weakly recurved, glabrous. Petals (1-)3-5(-7), dark yellow, oblong to broadly oblong, shortly clawed, nectary single, 0.5-1(-1.5) mm from petal base. Receptacle with basal collar of bristles. Achenes 15-50(-65), hardly flattened, glabrous 1.5-2 mm, beak straight, 1-1.5 mm long.

Similar Taxa

Confused with R. amphitrichus and R. glabrifolius. Species hybridizes with R. amphitrichus, the progeny of which are fertile (P. J. de Lange pers. obs.). Species is distinguished by the larger flower, with broad, irregularly spaced, oblong petals, whose nectary scale is virtually obscured by a dense cluster of carpels when viewed from above. In good habitat and growing conditions R. macropus is a very robust plant with very large, ternate leaves borne on stout petioles.

Flowering

September - April (but sporadic flowering may occur at anytime of the year)

Flower Colours

Yellow

Fruiting

October - July

Propagation Technique

Easy from the division of whole plants and from fresh seed. A wetland species which requires permanently damp but sunny situations, Good in shallow ponds.

Threats

Threatened by wetland drainage, modification and the spread of weeds. In large parts of its former range hybrids are now more commonly encountered than the actual species.

Chromosome No.

2n = 96

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 14 May 2014