Poor Knights spleenwort
Vascular – Native
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.
2n = c.288
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Threatened – Nationally Endangered | Qualifiers: EF, IE, RR
Previous conservation statuses
2009 | Threatened – Nationally Endangered | Qualifiers: EF
2004 | Threatened – Nationally Endangered
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.
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).
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.
Not applicable - spore producing
Not applicable - spore producing
Minute spores are wind dispersed (Thorsen et al., 2009).
Can be grown with considerable difficulty from spores, and has proved virtually impossible to maintain in cultivation.
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).
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.
Where To Buy
Not commercially available.
Fact Sheet prepared for NZPCN by P.J. de Lange 1 October 2003: Description modified from Brownsey & Jackson (1984) - but see also de Lange et al. (2010).
References and further reading
Brownsey, P.J.; Jackson, P.J. 1984: Asplenium pauperequitum - a new fern species from the Poor Knights Islands, New Zealand.. New Zealand Journal of Botany 22(2): 315-321.
Cameron, E.K.; de Lange, P.J.; Perrie, L.R.; Brownsey, P.J.; Campbell, H.J.; Taylor, G.A.; Given, D.R., Bellingham, E.M. 2006: A new location for the Poor Knights spleenwort (Asplenium pauperequitum, Aspleniaceae) on the Forty Fours, Chatham Islands. New Zealand Journal of Botany 44: 199-209.
de Lange, P.J.; Heenan, P.B.; Norton, D.A.; Rolfe, J.R.; Sawyer, J.W.D. 2010: Threatened Plants of New Zealand. Christchurch, Canterbury University Press.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 2009 Vol. 11 No. 4 pp. 285-309
Please cite as: de Lange, P.J. (Year at time of access): Asplenium pauperequitum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/asplenium-pauperequitum/ (Date website was queried)