Asplenium pauperequitum
Common names
Poor Knights spleenwort
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Ferns
Detailed description
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 × 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.
Distribution
Endemic. New Zealand: Poor Knights Islands, Mokohinau Islands (though probably extinct at this location). Discovered 2005 on the Chatham Islands where it is now known from Motchu Hara / The Forty Fours and several sites in the north-west of Rēkohu / Wharekauri / Chatham 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).
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Threatened – Nationally Endangered | Qualifiers: EF, RR
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).
Detailed taxonomy
Family
Synonyms
None
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Life cycle and dispersal
Minute spores are wind dispersed (Thorsen et al., 2009).
Propagation technique
Can be grown with considerable difficulty from spores, and has proved virtually impossible to maintain in cultivation.
Other information
Extra information
Story in Trliepidea about Poor Knight’s spleenwort being observed on the Chatham Islands.
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.
NVS code
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.
ASPPAU
Chromosome number
2n = c.288
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Threatened – Nationally Endangered | Qualifiers: EF, RR
2012 | Threatened – Nationally Endangered | Qualifiers: EF, IE, RR
2009 | Threatened – Nationally Endangered | Qualifiers: EF
2004 | Threatened – Nationally Endangered
Referencing and citations
References and further reading
Brownsey PJ, Jackson PJ. 1984. Asplenium pauperequitum – a new fern species from the Poor Knights Islands, New Zealand. New Zealand Journal of Botany 22(2): 315–321. https://doi.org/10.1080/0028825X.1984.10425260.
Cameron EK, de Lange PJ, Perrie LR, Brownsey PJ, Campbell HJ, Taylor GA, Given DR, Bellingham EM. 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. https://doi.org/10.1080/0028825X.2006.9513018.
de Lange PJ, Heenan PB, Norton DA, Rolfe JR, Sawyer JWD. 2010. Threatened Plants of New Zealand. Canterbury University Press, Christchurch. 471 p.
Thorsen MJ, Dickinson KJM, Seddon PJ. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285–309. https://doi.org/10.1016/j.ppees.2009.06.001.
Attribution
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).
NZPCN Fact Sheet citation
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)