Hymenophyllum pluviatile
Common name
filmy fern
Synonyms
None - first described in 2013
Family
Hymenophyllaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Ferns
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.
2009 | At Risk – Naturally Uncommon
Previous conservation status
2004 | Sparse
Distribution
Endemic. New Zealand: North and South Islands from about the Waima Forest, Hokianga south, and mainly in the west
Habitat
Coastal to montane. Usually on base-rich rocks in dark but dry places - though often in the vicinity of waterfalls, streams or rivers. Sometimes epiphytic in cloud forest. This species is often found growing with Hymenophyllum demissum and H. flexuosum.
Features
Epiphytic, terrestrial or rupestral ferns. Rhizomes brown, long-creeping, 360–840 microns in diameter, glabrous or with colourless hairs clustered around stipe bases. Stipes brown to dark brown, 30–90 mm long, 330–800 microns in diameter; wings poorly developed, often obvious only in the distal half of the stipe, with each wing usually less than 170 microns wide at mid-stipe and less than 500 microns at the stipe–rachis junction. Laminae 45–130 mm long, 20–67 mm wide; ovate or rarely triangular; apex attenuate to acute; base obtuse to truncate; green; glabrous; planate, or rachis wings and sometimes proximal axes flexuous; 4–5 pinnatifid, with 3-14-19 primary axes bearing quaternary axes, and the basal primary axis with 5–12 secondary axes bearing tertiary axes; primary pinnae 11-50 × 6-25 mm; axis-branching divaricate; segments entire, apices round or truncate, or sometimes shallowly emarginate. Sori orbicular or ovate. Indusial flaps 750–1340 × 660-1170 microns; apices round, truncate, or acute; apex usually irregularly dentate, or sometimes subentire.
Similar taxa
Hymenophyllum pluviatile is distinguished from H. flexuosum by its smaller size, narrower wings on the stipe and rachis, flatter lamina, narrower sori and usually irregularly dentate (cf. subentire) indusial flaps. Hymenophyllum pluviatile is distinguished from New Zealand populations of H. australe by its epiphytic, rupestral or terrestrial habitat (cf. growing in or around streams), its generally broader and more divided fronds, divaricating (cf. incurved) lamina axes, less developed stipe wings, and at most shallowly emarginate segment apices.
Flowering
Not applicable - spore producing
Flower colours
No flowers
Fruiting
Not applicable - spore producing
Propagation technique
Difficult - should not be removed from the wild
Threats
An extremely uncommon and lcoalised fern threatened by its small population sizes, and at one site - Mt Burnett - by dolomite mining. Previously regarded (as Hymenophyllum aff. flexuosum (AK 177370; Mt Burnett)) and treated either as ‘Sparse’ by de Lange et al. (2004) or ‘Naturally Uncommon’ by de Lange et al. (2009).
Etymology
hymenophyllum: Membranous leaf, from the Greek humen and phullon
pluviatile: From the Latin pluviatilis, meaning of rain or pertaining to rain.
Attribution
Fact Sheet prepared by P.J. de Lange 11 December 2013. Description from Perrie et al. (2013)
References and further reading
de Lange, P.J.; Norton, D.A.; Heenan, P.B.; Courtney, S.P.; Molloy, B.P.J.; Ogle, C.C.; Rance, B.D.; Johnson, P.N.; Hitchmough, R. 2004: Threatened and uncommon plants of New Zealand. New Zealand Journal of Botany 42: 45-76.
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 of New Zealand (2008 revision). New Zealand Journal of Botany 47: 61–96.
Perrie, L.R.; Shepherd, L.D.; de Lange, P.J.; Batty, E.L.; Ohlsen, D.J.; Bayly, M.J.; Brownsey, P.J. 2013: Hymenophyllum pluviatile, a new and uncommon fern from New Zealand. New Zealand Journal of Botany 51: 308–320.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Hymenophyllum pluviatile Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/hymenophyllum-pluviatile/ (Date website was queried)