Species:
	Ranunculus macropus
Common Name(s):
	Swamp buttercup
Threat Status:
	Data Deficient
Status 2004:
	Gradual Decline
Authority:
	Ranunculus macropus Hook.f.
Family:
	Ranunculaceae
Flora Category:
	Vascular - Native
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)
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

Where To Buy
Not commercially available.

Note
This species seems to be a shy flowerer, and is more often found in a sterile, vegetative state than reproductive. This trait is carried over into F1 hybrids. Hybrids are common wherever wetlands containing this species and R. amphitrichus have been modified, e..g, the wetlands of the lower Waikato.

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Last updated: 22 Feb 2010