Urtica australis
Common names
southern nettle, onga (Chatham I. only)
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Detailed description
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.
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.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | At Risk – Declining | Qualifiers: PD
Threats
Not Threatened Uncommon on Stewart Island. A cursed weed on the Chatham Islands. Relishes disturbance and is virtually untouched by large browsing animals.
Detailed taxonomy
Family
Urticaceae
Synonyms
Urtica aucklandica Hook.f.
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
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).
Other information
Where To Buy
Not commericially available.
Etymology
urtica: From the Latin verb urere which means “to burn”
australis: Southern
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
URTAUS
Chromosome number
2n = 24
Previous conservation statuses
2017 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
Attribution
Fact sheet prepared by P.J. de Lange for NZPCN (1 June 2013)
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Urtica australis Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/urtica-australis/ (Date website was queried)