The New Zealand Plant Conservation Network

Species

Asplenium pauperequitum

Etymology

Asplenium: From the Greek a- 'without' and splene 'spleen', a northern hemisphere species, the black spleenwort (Asplenium adiantum-nigrum), was once believed to be a cure for diseases of the spleen.

Common Name(s)

Poor Knights Spleenwort

Current Conservation Status

2012 - 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

2009 - Threatened - Nationally Endangered
2004 - Threatened - Nationally Endangered

Qualifiers

2012 - EF, IE, RR
2009 - EF

Authority

Asplenium pauperequitum Brownsey et P.Jackson

Family

Aspleniaceae

Flora Category

Vascular - Native

NVS Species Code

ASPPAU

Structural Class

Ferns

Synonyms

None

Distribution

Endemic. Poor Knights, Mokohinau Islands (though probably extinct at this location). Recently (February 2005) discovered on the Chatham Islands where it now known from the Forty Fours and several sites in the North West of the main Chatham (Rekohu) Island.

Habitat

A fern inhabiting semi- to heavily-shaded rock outcrops, where it grows in small colonies, with the rootlets tightly appressed to the damp rock walls. Plants are often associated with moisture loving, nitrogen fixing blue-green algae Nostoc, and grow in places where partially liquified sea bird guano accumulates. Plants seem intolerant of drying out and dislike high light levels - but will persist for some time in these habitats if the plants are mature (in such unfavourable conditions the fronds of stressed plants turn bright-green or yellow).

Features

Small tufted fern, forming dense colonies, usually within dark, damp overhangs. Rhizomes very short, erect. Stipes 10-120(-200) mm long, stipes and rachises dark red-brown (almost black), shiny, basal portion (especially) bearing fine hair-like scales. Fronds somewhat fleshy, deltoid in outline, pinnate to 2-pinnate, 30-100 x 25-80 mm, glossy dark green above (yellow green in stressed plants), pale beneath, glabrescent. Pinnae in 1-5 pairs, broadly ovate or broadly triangular, 3-lobed on largest fronds, margins smooth or slightly toothed. Sori up to 12 mm long, curving away from margins.

Similar Taxa

None.

Flowering

Not applicable - spore producing

Flower Colours

No Flowers

Fruiting

Not applicable - spore producing

Propagation Technique

Can be grown with considerable difficulty from spores, and has proved virtually impossible to maintain in cultivation.

Threats

Appears to be extinct on the Mokohinau Islands. On the Poor Knights Islands monitoring suggests that it is a species prone to seasonal or some other cyclic pattern, whereby populations rapidly expand and flourish before collapsing. Added to this apparently natural phenomena, Poor Knights plants have suffered from outbreaks of black scale and aphids, insect pests which seem to have been introduced to the islands by cannabis growers. Despite the Nature Reserve status of these islands some accessible populations were also severely damaged or completely destroyed by plant collectors. The Chatham Island populations seem secure because they are mainly remote from human habitation (Cameron et al. 2006,; de Lange et al. 2010).

Chromosome No.

2n = c.288

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Minute spores are wind dispersed (Thorsen et al., 2009).

This page last updated on 10 May 2014