Banks Peninsula fork fern
None (first described in 2010)
Vascular – Native
2n = c.416
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.
2018 | Threatened – Nationally Endangered
Previous conservation statuses
2012 | Threatened – Nationally Critical | Qualifiers: RR
2009 | Threatened – Nationally Critical | Qualifiers: DP, OL
2004 | Threatened – Nationally Critical
Endemic. New Zealand: South Island, Banks Peninsula
An epiphyte mostly found on the trunks of the tree ferns ponga (Cyathea dealbata), Smith’s tree fern (C. smithii) and wheki (Dicksonia squarrosa) within enclosed forest. It has also been collected once within the rich peaty soil produced by a species of harakeke/flax (Phormium sp.) growing on a cliff face.
Epiphytic or rarely terrestrial plants. Aerial stems pendulous, 70-510 mm long, not known to branch within the leafy part of the stem. Leaves spirally arranged, narrowly oblong to narrowly ovate, linear to falcate(-sigmoid), 10-25 x 2.5-6.5 mm; apex emarginate, truncate or cuspidate, with mucro 1-2 mm long. Synangia 2.5-6 x 1-2 mm, rounded to slightly biconic, with the lower surface of the sporangia appressed along all or most of their length to the subtending leaf margin, and points where present projecting laterally. Spores 71-83 x 35-39 microns. Description adapted from Perrie et al. (2010).
Tmesipteris horomaka is distinguished from T. elongata by its emarginate to truncate leaf apices and from T. tannensis by its more rounded synangia that do not project upwards from their subtending leaf. Tmesipteris horomaka is also distinguished from both these species by its octoploid chromosome number and generally larger spore size.
Not applicable - spore producing
Not applicable - spore producing
Difficult - should not be removed from the wild.
Currently known from 11 sites and an estimated c.75 plants based on the eight populations visited by Perrie et al. (2010). Therefore Tmesipteris horomaka easily qualifies for Threatened/Nationally Critical as there are less 250 mature individuals known. On the advice of Leon Perrie Tmesipteris horomaka had already been listed as Nationally Critical by de Lange et al. (2009) under the name Tmesipteris aff. tannensis (CHR 496779; Banks Peninsula) .
tmesipteris: From the Greek tmesis (cutting) and pteris (fern), alluding to the forked appendages on fertile fronds
Where to Buy
Not commercially available.
Fact sheet prepared for the NZPCN by\ P.J. de Lange (5 May 2010).
References and further reading
de Lange, P.J.; Norton, D.A.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Hitchmough, R.; Townsend, A.J. 2009: Threatened and uncommon plants New Zealand Journal of Botany 47: 61–96.
Perrie, L.R.; Brownsey, P.J.; Lovis, J.D. 2010: Tmesipteris horomaka, a new octoploid species from Banks Peninsula. New Zealand Journal of Botany 48: 15-29.
Townsend, A.J.; de Lange, P.J.; Norton, D.A.; Molloy, J.; Miskelly, C.; Duffy, C. 2008: The New Zealand Threat Classification System manual. Wellington, Department of Conservation.
Please cite as: de Lange, P.J. (Year at time of access): Tmesipteris horomaka Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/tmesipteris-horomaka/ (Date website was queried)