Hymenophyllum rarum
Common names
filmy fern
Biostatus
Native
Category
Vascular
Structural class
Ferns
Detailed description
Terrestrial or epiphytic, aromatic fern forming extensive, interwoven, creeping patches. Rhizomes long-creeping, very thin, brittle. Fronds pale grey-green (glaucescent). Stipes 20–70 mm long, very thin, wiry when fresh, very brittle when dry, glabrous, not winged; rachises very narrowly winged in upper part. Laminae 20–120 × 10–30 mm, narrowly ovate, narrowly elliptic, rarely deltoid, usually 2-pinnate, membranous, glabrous. Ultimate segments oblong, imbricate, margins smooth. Sori terminating the uppermost ultimate segments, ovoid completely immersed in lamina, few on each primary pinna, mostly confined to upper part of frond. Indusium flaps entire. (Description adapted from Brownsey & Smith-Dodsworth (2000)).
Similar taxa
Easily recognised by the peculiar grey-green, small, membranous fronds; by the smooth margins of the pinnae, ultimate segments and indusia; and by the sori which are sunk within the uppermost segments of the uppermost pinnae. Australian plants of H. rarum (which include the type of this species) are rather different differing by the non-aromatic, widely spaced rather than imbricating pale green, pinnae. The sori of Australian H. rarum are almost not wholly immersed within the pinnae nor confined to the uppermost segments of the uppermost pinnae. It seems likely that New Zealand plants referred to H. rarum may warrant recognition as a separate species. Further study into this matter is needed.
Distribution
Indigenous. New Zealand: North Island, South Island, Stewart Island/Rakiura, Chatham Islands, Auckland Islands. Also Australia.
Habitat
Coastal to montane. Common throughout the country in close forest, scrub, on shaded cliff faces, amongst boulders and in rubble slopes. Rather drought tolerant and often found growing in very exposed sites.
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.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- 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 | Not Evaluated
Detailed taxonomy
Family
Hymenophyllaceae
Synonyms
Mecodium rarum (R. Br.) Copel.; Hymenophyllum imbricatum Colenso; Hymenophyllum semibivalve Hook. et Grev.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Life cycle
Minute spores are wind dispersed (Thorsen et al., 2009).
Propagation technique
Difficult—should not be removed from the wild.
Other information
Etymology
hymenophyllum: Membranous leaf, from the Greek humen and phullon
rarum: Thin leaved; from the Latin rarus
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.
HYMRAR
Chromosome number
2n = 72
Previous conservation statuses
2017 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
References and further reading
Brownsey PJ, Smith-Dodsworth JC. 2000. New Zealand Ferns and Allied Plants. David Bateman, Auckland, NZ. 168 p.
Thorsen MJ, Dickinson KJM, Seddon PJ. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285–309. https://doi.org/10.1016/j.ppees.2009.06.001.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (20 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 rarum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/hymenophyllum-rarum/ (Date website was queried)