The New Zealand Plant Conservation Network

Species

Urtica australis

Etymology

Urtica: from the Latin verb urere which means "to burn"
australis: southern

Common Name(s)

Southern nettle, onga (Chatham I. only)

Current Conservation Status

2012 - Not Threatened

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 - Not Threatened
2004 - Not Threatened

Authority

Urtica australis Hook.f.

Family

Urticaceae

Flora Category

Vascular - Native

NVS Species Code

URTAUS

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

Urtica aucklandica Hook.f.

Distribution

Endemic to the South western Fiordland Coast, Stewart, Chatham and other main subantarctic islands.

Habitat

Abundant in coastal scrub and forest, favouring open ground, such as forest margins, open ground amongst scrub and grasses, and also cobble beaches and sand dunes. Common in damaged forest on the main Chatham Island.

Features

Stout semi-deciduous shrub forming dense bushes up to 1 x 1 m. Branches semi-erect to erect, rooting at base up to 1 x 0.1 m, somewhat woody at base, semi-succulent. Young branchlets, petioles and inflorescence axes sparsely to densely clad in stinging hairs, these sometimes completely absent from stems. Interpetiolar stipules lanceolate, usually bifid, 20 mm long. Petioles up to 50 mm long, stout, somewhat fleshy, often with a pair of lateral leaflets developed near petiole base. Leaves dark green, 100-150 x 80-140 mm, broadly ovate-cordate to suborbicular, acute to obtuse, coarsely dentate-serrate to subentire (rarely entire), teeth up to 10 mm long, stinging hairs confined to leaf margins and veins on leaf underside, often sparse or absent. Male inflorescence of 1-3 branched spikes up to 70 mm long; female inflorescence similar, flowers densely arranged, perianth in both sexes glabrate. Achenes (Seeds), pale brown, elliptic 1.5-2 mm.

Similar Taxa

Easily distinguished from all other indigenous and naturalised nettles by the broadly ovate, dark green leaves, 100-200 mm long, and stout shrubby semi-deciduous habit. It could perhaps be confused with the naturalised U. dioica but that species is distinctly long rhizomatous and has so far not been recorded from with the known range of U. australis. In New Zealand at least, both species can be easily distinguished by their chromosome number 2n = 24 in U. australis and 2n = 48 in U. dioica.

Flowering

December - January

Fruiting

December - March

Propagation Technique

Easy from fresh seed or by the division of root pieces. Dislikes drought and/or high humidity. Plants in these conditions are prone to sudden collapse. Because of the painful stings it is rarely grown. It is an ideal host plant for the red admiral butterfly (this species is the only known host plant for the endemic Chatham Island red admiral).

Threats

Not Threatened Uncommon on Stewart Island. A cursed weed on the Chatham Islands. Relishes disturbance and is virtually untouched by large browsing animals.

Chromosome No.

2n = 24

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 20 Jan 2014