The New Zealand Plant Conservation Network

Species

Polystichum wawranum

Etymology

Polystichum: Many rows (of sori); from the Greek polus and stikhos; parallel rows of spore cases

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

Polystichum wawranum (Szyszyl. in Wawra) Perrie

Family

Dryopteridaceae

Flora Category

Vascular - Native

NVS Species Code

POLWAW

Structural Class

Ferns

Synonyms

Aspidium wawranum Szyszyl. in Wawra

Distribution

Endemic. New Zealand, Northern North Island and Chatham Islands

Habitat

Coastal to montane. Often on cliff faces, especially those composed of base-rich substrates such as calcareous sandstone, limestone, basalt and schist. A rupestral or terrestrial fern of coastal shrublands and forest, gorges, riparian forest as well as open sites on hillsides, in rough pasture or on alluvial terraces. It has also colonise urban areas where it sometimes a feature of roadside banks and cuttings.

Features

Rhizomes short, erect. Stipes 150–550 mm long. Stipes and rachises densely scaly. Scales filiform (hair-like); almost always widest at base; those from the stipe-rachis junction 40–120 microns wide at mid length; usually dark brown, but often appearing black to the naked eye; apex long and tapering; margins often with protrusions, which are usually blunt; often densely fimbriate around base, so much so that in young fronds the stipe and rachis scales appear to be underlain by a dense white tomentum. Lamina 270–590 × 110–280 mm; bipinnate with the basal primary pinnae of some large fronds becoming tripinnate; varying in colour from olive-green to blue-green, usually with primary and secondary costae blackish blue. Primary pinnae in 18–35 pairs, the longest 55–140 × 13–35 mm. Secondary pinnae usually adnate, but becoming free and sessile to almost stalked towards the base of primary pinnae, particularly in basal primary pinnae; often with only sparse marginal toothing, sometimes almost entire but for apical point. Sori round. Indusia peltate, ± flat, ± round, with entire, although often undulate and/or scalloped, margins; often deciduous; central dark area usually insignificant (c. < 10% of surface area).

Similar Taxa

Polystichum wawranum is recognised by its hair-like scales, closely inserted and relatively long narrow pinnae, indusia mostly lacking obvious dark centres, and relatively small spores. It is likely to be confused only with P. neozelandicum subsp. neozelandicum and subsp. zerophyllum, which are distinguished from P. wawranum by having wider scales, indusia with larger dark centres, and larger spores. Polystichum wawranum is commonly sympatric with P. neozelandicum subsp. neozelandicum in northern New Zealand, otherwise its range overlaps with both P. neozelandicum subspecies only on the Chatham Islands.

Flowering

Not Applicable - Spore Producing

Flower Colours

No Flowers

Fruiting

Not Applicable - Spore Producing

Propagation Technique

Easily grown from fresh spores and transplants. However, often slow to establish. Does best in a shaded site planted within a deep, free draining humus-enriched fertile soil. Polystichum wawranum benefits from regular applications of lime.

Threats

Not Threatened - though very scarce on the Chatham Islands

Chromosome No.

2n = c.164

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 11 Jun 2014