Tmesipteris tannensis
Common names
fork fern
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Ferns
Detailed description
Rhizome dichotomously branched, brittle, 2.0–3.5 mm diameter. Aerial shoot developing over one to many years, but eventually terminating in a small appendage 0.1–0.5× the length of the largest leaves, simple, erect, suberect, or pendulous, 50–1200 mm long, triangular in cross-section, leaves and sporophylls spirally arranged. Leaves coriaceous, brittle, one surface deep glossy green, occasionally with a few stomata towards the far end, other surface dull green covered with stomata; shape variable often on same shoot, oblong, lanceolate, falcate, or ovate, 6–30 mm long × 2.5–9.0 mm broad; apex of leaf very variable often on the same plant, acute, obtuse to truncate, mucronate; mucro 1–2 mm long. Sporophylls developed in regular or irregular zones or throughout most of the shoot except for the lowermost part, equal to or slightly shorter than the leaves; 5–7 per 10 mm of shoot. Synangium 4.0–8.0 × 1.5–2.5 mm at point of attachment, biconic, persistent. Spores yellow, released in a mass, anisopolar, bilateral, monolete, foveolate, concavo-convex, 67–92 × 27–45 μm broad (longitudinal plane).
Similar taxa
Easily distinguished from all other named New Zealand species of fork fern by the biconic synangia. Tmesipteris horomaka Perrie, Brownsey, et Lovis, which is endemic to Banks Peninsula, is rather similar, differing mainly by its octoploid rather than tetraploid chromosome number and less distinctly biconic synangia.
Distribution
Endemic. New Zealand: North Island, South Island, Stewart Island/Rakiura, Chatham Islands, Auckland Islands.
Habitat
Coastal to subalpine. Terrestrial or epiphytic on a wide range of hosts and often sympatric with Tmesipteris elongata (less frequently with T. lanceolata and T. sigmatifolia). Less common in coastal and lowland areas in the far north where it is mostly known from higher elevation forest. However, steadily becoming more common from about Whangarei south.
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 | Not Threatened
Detailed taxonomy
Family
Synonyms
Lycopodium tannense Spreng.; Tmesipteris fowerakeri H.N.Barber, Tmesipteris forsteri sensu A.Cunn. nom. inv.,
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Propagation technique
Difficult— should not be removed from the wild.
Other information
Where To Buy
Not commercially available.
Etymology
tmesipteris: From the Greek tmesis (cutting) and pteris (fern), alluding to the forked appendages on fertile fronds
tannensis: Growing at Tanna, New Hebrides, where the species was first collected
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.
TMETAN
Chromosome number
2n = 208
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 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Regional conservation status of indigenous vascular plants in Otago” Jarvie S et al. (2024) report.
Otago: 2024 | Regionally Not Threatened
Referencing and citations
References and further reading
Chinnock RJ. 1975. The New Zealand Species of Tmesipteris (Psilotaceae). New Zealand Journal of Botany 13(4): 743–768. https://doi.org/10.1080/0028825X.1975.10430356.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (June 2009). Description adapted from Chinnock (1975).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Tmesipteris tannensis Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/tmesipteris-tannensis/ (Date website was queried)