Hymenophyllum australe
Common names
filmy fern
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Ferns
Detailed description
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 × 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.
Distribution
Endemic. New Zealand: North Island, South Island.
Habitat
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.
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 | At Risk – Naturally Uncommon | Qualifiers: RR, SO, Sp
Threats
Not threatened. A naturally uncommon, biologically sparse species which may be abundant in suitable habitats and then absent from other apparently suitable sites nearby.
Detailed taxonomy
Family
Synonyms
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.; Hymenophyllum atrovirens Colenso
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Propagation technique
Difficult - should not be removed from the wild
Other information
Etymology
hymenophyllum: Membranous leaf, from the Greek humen and phullon
australe: Southern, from the Latin australis
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.
HYMAUS
Chromosome number
2n = 72
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 | At Risk – Naturally Uncommon | Qualifiers: DP, RR, SO, Sp
2012 | At Risk – Naturally Uncommon | Qualifiers: DP, RR, Sp
2009 | At Risk – Naturally Uncommon
2004 | Sparse
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 Data Deficient | Qualifiers: TL
Referencing and citations
References and further reading
Bostock PD, Spokes TM. 1998. Hymenophyllaceae. Flora of Australia 48, Ferns Gymnosperms and allied groups: 116–148. ABRS/CSIRO Victoria, Australia.
Brownsey PJ, Smith-Dodsworth JC. 2000. New Zealand Ferns and Allied Plants. David Bateman, Auckland, NZ. 168 p.
Attribution
Fact Sheet Prepared for NZPCN by P.J. de Lange (June 2004 and updated 17 April 2011). Description adapted from Brownsey & Smith-Dodsworth (2000).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Hymenophyllum australe Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/hymenophyllum-australe/ (Date website was queried)