Hymenophyllum dilatatum


Hymenophyllum: Membranous leaf, from the Greek humen and phullon

Common Name(s)

Filmy fern, Matua mauku

Current Conservation Status

2012 - Not Threatened

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 - Not Threatened
2004 - Not Threatened


Hymenophyllum dilatatum (G. Forst.) Sw.



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 dilatatum (G. Forst.) Copel.; Sphaerocionium dilatatum (G.Forst.) C.Presl; Trichomanes dilatatum G.Forst.; Diplooephyllum dilatatum (G.Forst.) Bosch; Leptocionium sororium C.Presl


Endemic, New Zealand: North, South, Stewart, Chatham and Auckland Islands. Widespread except for the drier parts of the eastern South Island.


Coastal to montane in forest. Usually epiphytic or on fallen logs and banks, Very rarely on the forest floor or on boulders.


Epiphytic (very rarely terrestrial) fern. Rhizomes long-creeping, gracile, wiry when fresh very brittle when dry. Stipes often widely spaced on rhizomes, 20-150(-200) mm long, stout, glabrous, distinctly though narrowly winged for part of length; rachises broadly winged throughout. laminae 80-400(-800) × 40-150(-160) mm, ovate, narrowly ovate to lanceolate, 3-4-pinnate, bright to dark green, glabrous. Ultimate segments rather broad, margins smooth, plane. Sori terminating ultimately segments, slightly sunk in lamina, many on each primary pinna. Indusial flaps smooth. Description adapted from Brownsey & Smith-Dodsworth (2000).

Similar Taxa

Easily distinguished from all other Hymenophyllum by the glabrous, smooth margined fronds; by the conspicuous broad, flat wing bordering much of the stipe and all of the rachis; and by the very broad pinnae.



Flower Colours

No Flowers



Propagation Technique

Difficult - should not be removed from the wild


Not Threatened

Chromosome No.

2n = 72

Endemic Taxon


Endemic Genus


Endemic Family


Life Cycle and Dispersal

Minute spores are wind dispersed (Thorsen et al., 2009).

Where to Buy

Not commercially available



Fact sheet prepared for NZPCN by P.J. de Lange (17 April 2011). Description adapted from Brownsey & Smith-Dodsworth (2000).

References and further reading

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

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309

This page last updated on 30 May 2015