The New Zealand Plant Conservation Network

Species

Pouzolzia australis

Etymology

australis: southern

Common Name(s)

Kermadec nettle-tree

Current Conservation Status

2018 - Threatened - Nationally Endangered

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

2012 - At Risk - Naturally Uncommon
2009 - At Risk - Naturally Uncommon
2004 - Threatened - Nationally Endangered

Qualifiers

2012 - EF, RR, TO
2009 - OL, IE

Authority

Pouzolzia australis (Endl.) Friis et Wilmot-Dear

Family

Urticaceae

Brief Description

Small bushy tree bearing light green soft wrinkled triangular pointed leaves that have prominent veins on the whiteish underside inhabiting Raoul Island in the Kermadec Islands. Wood soft. Leaves 7-15cm long, edge with evenly spaced teeth. Flowers tiny, in small round clusters at base of leaves.

Flora Category

Vascular - Native

NVS Species Code

POUAUS

Structural Class

Dicotyledonous Trees & Shrubs

Synonyms

Boehmeria dealbata Cheeseman, Boehmeria australis var. dealbata (Cheeseman) Sykes, Boehmeria australis subsp. dealbata (Cheeseman) Sykes, Boehmeria calophleba C.Moore et F.Muell

Distribution

As currently circumscribed by Wilmot-Dear & Friis (2006) Pouzolzia australis is indigenous to Norfolk and Lord Howe Islands as well as the Kermadec Islands, where it is now known only from Raoul and Macauley Islands. While the merger of Boehmeria australis subsp. dealbata with B. australis subsp. australis into Pouzolzia as P. australis seems sensible, the merger of the very distinctive Lord Howe endemic Boehmeria calophleba requires further critical study before it should be universally followed. For a concise explanation of the differences between Boehmeria and Pouzolzia see Wilmot-Dear et al. (2009).

Habitat

Coastal forest, cliff faces, recent and semi-stable slips, low scrub.

Features

Shrub or small tree up to 8 m tall. Branchlets at first covered in fine white pubescence, maturing with age grey. Leaves alternate, 60-200 x 30-60 mm, ovate-ovate-lanceolate, borne on stout petioles 25 to 30 mm long, leaf apex acuminate, upper surface glabrescent, rugulose to almost smooth, undersides finely clad in dense white hairs (so giving a white colour to leaf undersides). Midrib and veins prominent, glabrescent, yellow-green. Inflorescences numerous, sessile, axillary glomerules (clusters). Male flowers with acuminate perianth segments 2-3 mm long, clad in stiff hairs, females with tubular perianth up to 2 mm long, contracted at 2-toothed apex; stigma filiform, protruding. Fruits compressed, broadly winged, the ovoid achenes minute.

Similar Taxa

None within the New Zealand Botanical Region (for a definition of this area see Allan 1961) Wilmot-Dear & Friis (2006) transferred Boehemeria australis to Pouzolzia and in the process reduced the Lord Howe endemic B. calophleba and Kermadec Islands endemic B. australis subsp. dealbata into P. australis. While their conclusion about the Lord Howe species needs further investigation (the Lord Howe plant is very different from the Norfolk and Kermadec Island plants), their decision about Kermadec and Norfolk plants seems justified. Previously the Kermadec plant had been distinguished from the Norfolk Island nettle tree by its having somewhat whiter undersides to the leaves, and by its slightly less rugose upper leaf surface (see Sykes in de Lange et al. 2005). These distinctions seem relatively minor and without further investigation using modern molecular tools it does seem that the more detailed morphological analysis by Wilmot-Dear & Friis (2006) should be followed.

Flowering

Year round

Flower Colours

Brown,White

Fruiting

Year round

Propagation Technique

Very easily grown from fresh seed and cuttings. Plants often arise spontaneously in cultivation from the abundant viable seed produced by established specimens. Very cold sensitive.

Threats

Formerly threatened with extinction through heavy browsing pressure from goats. Following the eradication of goats from Raoul Island Kermadec nettle tree did not at first recover. Indeed it seems to have declined further and for a decade or so it became very scarce. It was presumed that this was caused by competition from weed species, which had, following the goat eradication, rapidly spread into the type of habitat it was assumed Kermadec nettle tree requires. Current fieldwork now suggests that Kermadec nettle tree is rapidly spreading and colonising new habitats, such that it is no longer considered to be a seriously threatened plant. In May 2011 Pouzolzia was rediscovered on Macauley Island where it had been believed to have gone extinct over a 100 years before.

Chromosome No.

2n = 28

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

This page last updated on 19 Dec 2014