Pomaderris hamiltonii

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Species

Pomaderris hamiltonii

Etymology

Pomaderris: lid skin
hamiltonii: Named after W. S. Hamilton (of Southland)

Common Name(s)

Pale-flowered kumarahou

Current Threat Status

2012 - At Risk - Naturally Uncommon

Previous Threat Status

2009 - At Risk - Naturally Uncommon
2004 - Sparse

Qualifiers

2012 - RR, Sp
2009 - RC

Authority

Pomaderris hamiltonii L.B.Moore

Qualifiers

RC

Family

Rhamnaceae

Brief Description

Rare shrub to 4m tall with soft oval pointed leaves which have prominent veins on the underside and sprays of pale cream flowers. Leaves 5-6.5cm long by 2-3cm wide, tip pointed, with white star-shaped hairs underneath (lens needed). Fruit dry, small.

Flora Category

Vascular - Native

Synonyms

None

Distribution

Endemic. North Island only, vicinity of Warkworth and Omaha, near Kaiaua and Miranda and on Great Barrier Island

Habitat

Coastal to lowland in open successional habitats and shrubland. Often found along roadside cuttings where the constant disturbance provides an ideal habitat.

Features

Shrub to small tree 3-6 m tall. branches upright rarely spreading, branches slender, bark dark brown, finely rugose. Seedling leaves dark green and glossey above, pale, and dull beneath, margins finely toothed. Leaves of seedlings, juveniles and adults petiolate, petioles pliant, dark green to brown green, somewhat rugose, at first finely covered in stellate hairs, trending to glabrous with age. Adult leaves 20 -80 x 10-40 mm, dark green above (not glossey), pale grey-green beneath, elliptic to elliptic-ovate; upper surface glabrous except for sparse, simple hairs present toward the sunken midrib; lower surface covered with fine, grey stellate indumentum, with larger simple and stellate veins on midribd and veins; margins entire, sometimes revolute; stipules 4-5 mm long, caducous. Inflorescence a terminal, open, many-branched corymb. Calyx reflexed, pale greenish; tube with scattered long, white, simple hairs until after anthesis. Petals cream; limb broad. Anthers oblong. Ovary with stellate hairs at apex, wholly immersed in calyx tibe at anthesis, ½ immersed at fruiting. Fruit cocci opening by percula, occupying ½ of their inner faces.

Similar Taxa

Pomaderris kumeraho A.Cunn. is superficially similar. However, it is more usually a small shrub (1-2 m tall) with smaller, broadly oval, elliptic to elliptic-ovate, grey-green rather than dark green, much hairer leaves. It is also distinguished by its yellow rather than cream-coloured flowers. In P. hamiltonii the calyx tube is sparingly covered by long simple hairs and the petals are cream, while in P. kumeraho the calyx tube is densely covered by long simple hairs and the petals are yellow. The two species often grow sympatrically. Pomaderris kumeraho has 2n = 24 chromosomes and produces seed sexually, P. hamiltonii is triploid (2n = 36) and produces seed through apomixis.

Flowering

(August-) October (-November)

Main Flower Colour

Cream

Other Flower Colour

Black

Fruiting

(November-) December - January

Propagation Technique

Easy from fresh seed, though this can be slow to germinate. Semi-hardwood cuttings strike with difficulty. Recent experimentation has found that cuttings strike well if placed in untreated saw dust. Once established this species often naturalises in suitable gardens. It is an attractive small tree which makes and excellent shelter belt or specimen tree. It is inclined to be short-lived and is prone to verticillium wilt.

Threats

Many populations occur on roadside cuttings where they are at constant risk from road maintenance crews, roadside spraying, and road widening. Some populations have been lost through natural succession

Chromosome No.

2n = 36

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 12 Dec 2014

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