The New Zealand Plant Conservation Network

Species

Parapolystichum kermadecense

Common Name(s)

Raoul Island shield fern

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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 - At Risk - Naturally Uncommon

Qualifiers

2012 - IE, OL
2009 - IE, OL

Authority

Parapolystichum kermadecense (Perrie et Brownsey) Perrie et L.D. Sheph.

Family

Dryopteridaceae

Flora Category

Vascular - Native

Structural Class

Ferns

Synonyms

Lastreopsis kermadecensis Perrie et Brownsey

Distribution

Endemic. Kermadec Islands: Raoul Island

Habitat

Common in the 'wet' forest of Raoul Island where it is a frequent ground cover fern, it also extends into the 'dry' forest of that island, though there it is much less common. Within its habitat range it commonly associates with the ferns Pteris comans, Doodia australis, D. milnei, Microsorum pustulatum subsp. pustulatum and, less commonly, Arachniodes aristata, the sedge Carex kermadecensis and seedlings of common forest trees, most especially the palm Rhopalostylis baueri (Perrie & Brownsey 2012)

Features

Terrestrial fern. Rhizomes erect or short creeping with fronds clustered at apex. Rhizome scales similar to, but narrower than, those on stipe, non-clathrate, margins entire to abundantly ciliate, cilia apices sometimes globular. Stipes stramineous to castaneous, darker towards the rhizome, 100-500 × 1-4 mm diameter, lacking hairs or with scattered hairs 250-700 mm long, scaly proximally. Stipe scales brown to dark-brown, the more distal clathrate, narrowly-triangular or narrowly ovate, 5.0-12.0 × 0.8-2.1 mm, margins entire to repand (or ciliate). Laminae green, paler abaxially, 3-pinnate to 3-pinnate-pinnatifid, with 8-13 pairs of primary pinnae of which 0-1(-2) catadromous, angular-ovate to pentagonal, 145-450 × 100-330 mm wide, apex acuminate. Rachises 140-420 mm long, adaxial sulcus densely set with erect ctenitoid hairs, the hairs 80-180 mm long, reddish-clear to red or orange; abaxially glabrous or proximally nearly so, or with scattered hairs, often clustered at junctions with primary pinnae and sometimes many distally, the hairs clear with red transverse cell walls, mostly 170-350 mm long, occasionally or commonly interspersed with longer hairs up to 700 mm. Proximal pair of primary pinnae 75-250 × 50-210 mm, with proximal basiscopic secondary pinna enlarged, 35-150 × 11-45 mm.Primary pinnae in apical third of lamina pinnate-pinnatifid, very occasionally 2-pinnate with ½-1 pair of secondary pinnae.Ultimate segments sparsely serrate-crenate, the apex obtuse to acute but with several teeth.Costa of primary pinnae adaxially with hairs similar to those of adaxial rachis, but paler and up to 270 mm long, thinning distally so that minor veins and lamina usually glabrous or nearly so; abaxially glabrous or densely hairy, especially proximally, the hairs usually inconspicuous, clear or reddish clear, predominantly ctenitoid, 170-270 mm long, thinning distally so that minor veins and lamina almost glabrous, sinuses between secondary pinnae with no or few hairs. Glands inconspicuous, absent or few on abaxial rachis, few to many on abaxial lamina, yellow to orange, often pale, 70-140 mm.Sori circular, 0.9-2.1 mm in diameter. Indusia persistent, round to ovate, cordate with a narrow to broad sinus, brown to reddish-brown, 0.7-1.3 mm diameter, only partially covering mature sori, glands absent or present on the dorsal surface or margin. Spores monolete 29-34 × 22-27 µm.

Similar Taxa

Parapolystichum kermadecense is the only species present on the Kermadec Islands group (where it is found only on Raoul Island). As such, in the field it is unlikely to be confused with any other terrestrial fern on that island, or any other Parapolystichum. However, from other Parapolystichum species it can be distinguished by the short hairs in the sulcus on the adaxial rachis; by the abaxial rachis being sparsely hairy; by the abaxial lamina having inconspicuous sparse glands and by its tetraploid chromosome number.

Flowering

Not applicable - spore producing

Fruiting

Not applicable - spore producing

Propagation Technique

Can be grown from spores and transplanted but difficult to maintain. Needs room to spread and cold sensitive. Does best in a warm, sheltered, shaded site, planted in a free draining, moist, fertile soil.

Threats

Widespread and common on Raoul Island. This species is listed only because on a global scale, as an island endemic it occupies a small area. Beyond natural threats, such as volcanic activity and earthquakes, there are no known, human-induced threats affecting this species. For this reason it has previously been listed, appropriately as "At Risk/Naturally Uncommon" under the informal name of ‘Lastreopsis aff. glabella (AK 242151; Raoul Island)’ by de Lange et al. (2009). Despite its formal elevation to species rank there is no need to change this threat status (see comments by Perrie & Brownsey 2012).

Chromosome No.

2n = 164

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 14 Jan 2018