Mercury Bay weed
Vascular – Exotic
Herbs - Dicotyledons other than Composites
North Island: North. Auckland (Kawau Island) to Wellington; South Island: Christchurch.
Widely planted as a lawn in warmer parts of New Zealand and in many places it has thrived and spread naturally to a limited extent.
Wetland plant indicator status rating
FACU: Facultative Upland
Occasionally is a hydrophyte but usually occurs in uplands (non-wetlands).
Perennial herb, with most parts densely hairy; hairs white, ± appressed, forked. Stems stoloniferous, freely branching, purplish, forming extensive mats or low cushions to 5 cm high. Lf internodes 1-2 cm long; petioles erect or nearly so, to 6 cm long, short on very exposed stolons. Lamina (5)-10-30 mm diam., suborbicular to reniform, membranous, glabrous or nearly so and dull above, with appressed hairs below; veins raised beneath, not impressed above; base broad-cordate; apex rounded or slightly emarginate. Peduncles 5-15 mm long, bract very small and inconspicuous. Calyx c. 2 mm long, densely hairy outside; lobes alternately linear-oblong and ovate-oblong, obtuse to subacute. Corolla 4-5 mm diam., greenish white, lobed to c. 1/2 way; lobes narrow-oblong to lanceolate, = calyx lobes at anthesis, becoming > calyx lobes. Anthers violet or violet-margined. Ovary densely hairy. Capsule usually deeply 2-lobed, with 1-(2) seeds per loculus, 2-2.5 × 4-5 mm, more rarely only 1 locule developed, indehiscent, slightly to strongly hispid, > calyx. Fruiting calyx to 3 mm long, fruiting peduncle recurved. Seeds c. 1.5 mm long, yellow to dark brown.
Disnighished from the native Dichondra by the glabrous to glabrate leaves and the habit - found in urban lawns.
West Indies, S. North America
dichondra: Two seeds
micrantha: Tiny flower
This name may be incorrectely used for the exotic Dichondra in New Zealand. Previously reffured to as the indigenous D. repens.
Fact sheet prepared by Marley Ford (3 October 2022). Brief description, Distribution, Habitat, and Features sections copied from Webb et al. (1988).
References and further reading
Webb C.J., Sykes W.R., & Garnock-Jones P.J. (1988). Flora of New Zealand Volume 4. DSIR, Botany Division.