Species

Hymenophyllum bivalve

Etymology

Hymenophyllum: Membranous leaf, from the Greek humen and phullon

Common Name(s)

Filmy fern

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

Authority

Hymenophyllum bivalve (G. Forst.) Sw.

Family

Hymenophyllaceae

Flora Category

Vascular - Native

NVS Species Code

HYMBIV

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

Ferns

Synonyms

Meringium bivalve (G. Forst.) Copel.; Sphaerocionium bivalve (G.Forst.) C.Presl; Trichomanes bivalve G.Forst.; Hymenophyllum pyriforme Bosch; Hymenophyllum spathulatum Colenso

Distribution

Indigenous. New Zealand: North, South, Stewart, Chatham and Auckland Islands. From Campbells Bay (Auckland) south, though scarce north of the Waikato. Also Australia (Queensland to New South Wales)

Habitat

Coastal to montane forest. Either terrestrial or a low epiphyte on tree trunks and exposed roots.

Features

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 degrees to the plant of 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.

Flowering

N.A.

Flower Colours

No Flowers

Fruiting

N.A.

Propagation Technique

Difficult - should not be removed from the wild

Threats

Not Threatened

Chromosome No.

2n = 44

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

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

Where to Buy

Not commercially available

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).

References and further reading

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

Bostock, P.D.; Spokes, T.M. 1998: Hymenophyllaceae: Flora of Australia 48: 116-148.

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 29 May 2015