Hymenophyllum bivalve
Common names
filmy fern
Biostatus
Native
Category
Vascular
Structural class
Ferns
Detailed description
Delicate, mat-forming terrestrial or low epiphytic fern. Rhizomes long-creeping, rather gracile, wiry, pliant, sparsely hairy; hairs dark brown, appressed. Frond pendulous in epiphytic plants otherwise with erect stipes and laminae lying horizontal. Stipes well spaced on rhizomes, 30–150–(180) mm long, slender, not-winged ± glabrous (sometimes with sparse hairs near base and apex); rachises narrowly winged throughout. Laminae 60–200 × 30–160 mm, light green, ± glabrous, broadly triangular to broadly ovate with apex deflexed, deeply 3–4-pinnate, primary pinnae often up-curved. Ultimate segments linear, 0.3–1.5 mm wide, obtuse, margins shallowly toothed. Sori numerous, terminating ultimate segments, slightly sunken in lamina, many on each primary pinna. Involucre round to ovoid, bilabiate, almost divided almost to base, 0.8–1.5 mm long × 0.5–1.5 mm wide; base cuneate, only slightly immersed; indusial flaps entire, smooth-edged; receptacle included or slightly exserted. (Description adapted from Bostock & Spokes (1998) and Brownsey & Smith-Dodsworth (2000)).
Similar taxa
Sterile plants are virtually impossible to distinguish from Hymenophyllum multifidum but when fertile this species is easily recognised by the much smaller sori which are held horizontally or slightly bent but never bent at 90° to the the frond as in H. multifidum. The fronds of H. bivalve are slightly larger than those of H. multifidum, brighter green, notably less prominently curled downwards, and the margins are more finely and less deeply toothed.
Distribution
Indigenous. New Zealand: North Island (from Campbells Bay (Auckland) south, though scarce north of Waikato), South Island, Stewart Island/Rakiura, Chatham Islands, Auckland Islands. Also Australia (Queensland to New South Wales).
Habitat
Coastal to montane forest. Either terrestrial or a low epiphyte on tree trunks and exposed roots.
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 | Qualifiers: SO
Detailed taxonomy
Family
Synonyms
Meringium bivalve (G. Forst.) Copel.; Sphaerocionium bivalve (G.Forst.) C.Presl; Trichomanes bivalve G.Forst.; Hymenophyllum pyriforme Bosch; Hymenophyllum spathulatum Colenso
Endemic taxon
No
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
Other information
Where to Buy
Not commercially available
Etymology
hymenophyllum: Membranous leaf, from the Greek humen and phullon
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.
HYMBIV
Chromosome number
2n = 44
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 | Qualifiers: SO
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
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 Not Threatened
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.
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 Bostock & Spokes (1998) and Brownsey & Smith-Dodsworth (2000).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Hymenophyllum bivalve Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/hymenophyllum-bivalve/ (Date website was queried)