Species

Trichomanes caudatum

Etymology

caudatum: with a tail

Current Conservation Status

2018 - Threatened - Nationally Critical

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

2012 - At Risk - Naturally Uncommon
2009 - Threatened - Nationally Critical

Qualifiers

2012 - DP, OL, SO

Authority

Trichomanes caudatum Brack.

Family

Hymenophyllaceae

Flora Category

Vascular - Native

Structural Class

Ferns

Synonyms

Cephalomanes caudatum (brack.) Bostock; Macroglena caudata (Brack.) Copel.; Abrodictyum caudatum (Brack.) Ebihara et K. Iwats.

Distribution

Indigenous. Kermadec Islands (Raoul Island); New Zealand (North Island). Also the wider Pacific, eastern Australia (Queensland to Victoria), New Guinea, Malesia, New Caledonia, Fiji, Samoa, Tahiti and Rarotonga.

Habitat

Epiphytic on the trunks of wheki (Dicksonia squarrosa) in lowland, riparian forest

Features

Diminutive, epiphytic fern. Rhizome long creeping 1-1.5 mm diameter, densely clothed with spreading bristle-like dark red-brown multicellular hairs. Fronds crowded toward rhizome apex, 10-20 mm long. Stipes 3-5 mm long, bearing two faint longitudinal ridges. Frond lamina deeply 1-2(-3) pinnatifid, broadly deltoid to narrowly ovate, 8-10(-12) mm wide, membranous, ± pale green; apex erect, ultimate segments linear, 1-3 mm long, 0.3-0.4 mm wide, ± glabrous. Sori inconspicuous, immersed in the apices of basal segments of secondary pinnae, involucre funneliform, 0.2-0.5(-1.0) mm long, 0.3-0.6 mm wide at apex, narrowly winged for most of length, ± narrowly triangular, mouth lobed 4x, lobes entire, spreading; receptacle exserted.

Similar Taxa

The mainland New Zealand form of Trichomanes caudatum is superficially similar to T. endlicherianum and T. venosum. From Trichomanes endlicherianum it differs by its deltoid frond and by the lobed involucre of the fruiting receptacle. Further it differs by its ecology as T. endlicherianum is rarely found in this country as an epiphyte, while T. caudatum in New Zealand, as elsewhere in the world, is strictly epiphytic. From Trichomanes venosum, T. caudatum differs by having a deltoid frond, and especially by the obvious lack of distinct veins within the fronds. New Zealand plants of T.richomanes caudatum may yet warrant formal recognition as a separate species or subspecies (B.S. Parris pers. comm.). In particular they are much smaller than this species usually is overseas, they have a less well defined creeping rhizomatous habit, and the fronds are much smaller and less divided than is usual for this species, furthermore the involucre is distinctly divided into 4 entire lobes (it is usually entire in T. caudatum). However, Trichomanes caudatum is a highly variable species and sequences of the New Zealand plant are the same as samples of T. caudatum from Fiji so it seems best for now to place our plant there. Raoul Island Trichomanes caudatum are different again and they would repay further study.

Flowering

N.A.

Flower Colours

No Flowers

Fruiting

N.A. Fruiting material appears to be present in the New Zealand population throughout the year

Propagation Technique

Difficult - should not be removed from the wild

Threats

Currently this species is known from a single site in New Zealand where it is present on < 10 wheki (Dicksonia squarrosa) in a small are of riparian forest. The host trees are at risk from flooding, weeds and, as they grow alongside a popular walking track, vandalism. The population has declined since it was first discovered in the late 1990s as some host trees have died. The population is being carefully monitored by the Department of Conservation. As this fern was found by chance and it is very easily  overlooked it is quite likely that further populations exist elsewhere in New Zealand. On Raoul Island (Kermadec Islands group) it is known from a single site near the summit of that island.

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

Where To Buy

Not commercially available

Notes

Recently (May 2011) Trichomanes caudatum has been discovered on Raoul Island in the Kermadec Islands group. On Raoul it is scarce. Raoul plants match the widespread Pacific morph of this species (they are not a close match for the New Zealand plant). Previously NZPCN had followed Ebihara et al. (2006) in recognising Abrodictyum as distinct frm Trichomanes - recently Brownsey & Perrie (2016) have rejected this idea favouring a return to the past broad circumscription of Trichomanes used in New Zealand.

Brownsey & Perrie (2016) also note that New Zealand Trichomanes caudatum match the race of it found on Fiji but that these plants appear different to the race found on Raoul Island.

Attribution

Fact sheet prepared for NZPCN by P.J. de Lange 10 March 2011. Description modified from Bostock & Spokes (1998) using measurements taken from the limited New Zealand herbarium material available. Notes on variability of A caudatum in New Zealand from B.S. Parris (pers. comm.)

References and further reading

Bostock, P.D.; Spokes, T.M. 1998: Hymenophyllaceae. Flora of Australia. Vol. 48: 116-148.

Brownsey, P.J. & Perrie, L.R. 2016: Hymenophyllaceae. In: Breitwieser, I.; Heenan, P.B.; Wilton, A.D.
Flora of New Zealand - Ferns and Lycophytes. Fascicle 15. Manaaki Whenua Press, Lincoln.


Ebihara, A.; Dubuisson, J-Y.; Iwatsuki, K.; Hennequin, S.; Ito, M. 2006: A taxonomic revision of the Hymenophyllaceae. Blumea 51: 2-57

This page last updated on 4 Apr 2016