Hymenophyllum demissum
Common names
drooping filmy fern, Irirangi, piripiri
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Ferns
Detailed description
Terrestrial or epiphytic fern forming large patches made up of numerous densely (more rarely diffuse) packed fronds. Rhizomes long-creeping, slender. Stipes 40–170 mm long, stout, pliant, wiry, glabrous usually not-winged, if winged then wing minute; rachises narrowly winged throughout. Laminae elliptic, ovate or narrowly ovate, 3–4-pinnate, 70–250 × 30–150 mm, pale green to dark green, glabrous. Ultimate segments oblong, margins smooth. Sori numerous on the terminal ends of the ultimate segments of the primary pinna. Indusial flap margins smooth or minutely toothed. (Description adapted from Brownsey & Smith-Dodsworth (2000)).
Similar taxa
Easily recognised by the extremely wiry usually un-winged stipe, large glabrous fronds, smooth-margined pinna segments, and when fertile by the numerous, narrow, paired sori. When dry the fronds of this species rarely curl up.
Distribution
Endemic. New Zealand: Kermadec Islands (Raoul Island), North Island, South Island, Stewart Island/Rakiura, Chatham Islands, Auckland Islands. Widespread except for the drier parts of the eastern South Island.
Habitat
Coastal to montane in forest. Usually terrestrial where it typically forms dense carpets on the ground, on banks or on rotting logs. Also epiphytic, and then found mostly on the basal trunks of forest trees and tree ferns. Sometimes found in forest growing over boulders, rocks and on cliff faces.
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 | Not Threatened
Detailed taxonomy
Genus
Family
Synonyms
Mecodium demissum (G. Forst.) Copel.; Hymenophyllum australe var. aucklandicum (Bosch) C.Chr.; Sphaerocionium demissum (G.Forst.) C.Presl; Trichomanes demissum G.Forst.; Hymenophyllum aucklandicum Bosch;
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Life cycle and dispersal
Minute spores are wind dispersed (Thorsen et al., 2009).
Propagation technique
Difficult—should not be removed from the wild
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
UPL: Obligate Upland
Rarely is a hydrophyte, almost always in uplands (non-wetlands).
Other information
Etymology
hymenophyllum: Membranous leaf, from the Greek humen and phullon
demissum: Drooping; from the latin demissus; referring to the leaves when the plant is perched on trees
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.
HYMDEM
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 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
Otago: 2024 | Regionally Not Threatened
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.
Auckland: 2025 | Regionally Not Threatened | Qualifiers: DPS, DPT
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Auckland conservation status information is sourced from the “Conservation status of vascular plant species in Tāmaki Makaurau / Auckland” Simpkins E et al. (2025) report.
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 (17 April 2011). Description adapted from Brownsey & Smith-Dodsworth (2000).