Hymenophyllum australe


Hymenophyllum: Membranous leaf, from the Greek humen and phullon
australe: southern, from the Latin australis

Common Name(s)

Filmy fern

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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

2009 - At Risk - Naturally Uncommon
2004 - Sparse


2012 - DP, RR, Sp


Hymenophyllum australe Willd.



Brief Description

Hymenophyllum atrovirens Colenso

Flora Category

Vascular - Native

NVS Species 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.

Structural Class



Mecodium atrovirens (Colenso) Copel.; Hymenophyllum australe var. atrovirens (Colenso) C.Chr.; Hymenophyllum javanicum var. atrovirens (Colenso) Hook. et Baker; Hymenophyllum montanum Kirk; Mecodium montanum (Kirk) Copel.


Endemic. New Zealand, North and South Islands.


Hymenophyllum australe is almost and exclusively rheophytic species found in dark dripping wet overhangs and holes within the flood zone of deeply shaded or densely forested steep sided rivers, river canyons, river gorges, under and around waterfalls and in seepages along the banks of narrow streams. It is only very rarely found away from waterways.


Inconspicuous, colonial fern of dark holes, overhangs and rock faces, usually growing in or near water. Fronds dark green to black-green. Stipes 10-60 mm, membranous, glabrous, winged almost to base; wing intially rather broad but tapering gradually from the rachis along the stipe, almost to the stipe base, wing flat, sometimes undulating, occasionally markedly crinkly (this often varying within the same plant). Frond distinctly deltoid to narrowly deltoid, 2-3-pinnate, 30-140 x 10-60 mm, very dark green to black green (sometimes purple-black). Ultimate segments linear or oblong, margins smooth. Sori terminal on ultimate segments, protruding (not sunken into lamina), solitary or paired, mainly on the primary pinna. Indusium flaps either smooth-edged or notched.

Similar Taxa

This species is most likely to be confused with H. flexuosum from which it differs by its usually much smaller, strongly deltoid, dark green to almost black-green rather than bright green to green fronds, and a very broad, less markedly undulating (crisped) stipe and rachis membranous wing which gradually tapers from the rachis (its widest point) to almost the stipe base. Hymenophyllum pluviatile is superficially similar but in New Zealand it occupies a completely different habitat on boulders rocks and stones in dense forest (though often near streams and rivers). On occasion H. pluviatile can be epiphytic.


Not applicable - spore producing

Flower Colours

No Flowers


Not applicable - spore producing

Propagation Technique

Difficult - should not be removed from the wild


Not threatened. A naturally uncommon, biologically sparse species which may be abundant in suitable habitats and then absent from other apparently suitable sites nearby.

Chromosome No.

2n = 72

Endemic Taxon


Endemic Genus


Endemic Family


Where to Buy

Not commercially available




Fact Sheet Prepared for NZPCN by P.J. de Lange(June 2004 and updated 17 April 2011). Description adapted from Brownsey & Smith-Dodsworth (2000).

References and further reading

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

Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand Ferns and Allied Plants. Auckland, David Bateman

This page last updated on 30 Nov 2016