Hymenophyllum peltatum

Species of fern

Hymenophyllum peltatum

Scientific classification
Kingdom:  | Plantae
Clade:  | Tracheophytes
Division:  | Polypodiophyta
Class:  | Polypodiopsida
Order:  | Hymenophyllales
Family:  | Hymenophyllaceae
Genus:  | Hymenophyllum
Species:  |

H. peltatum

Binomial name
Hymenophyllum peltatum

(Poir.) Desv.

Hymenophyllum peltatum, also known as alpine filmy-fern, is a species of filmy fern widely distributed across Australia, New Zealand, South Africa, South America.[1][2][3][4] It is predominantly a rainforest species with delicate foliage arrangements. Members of the Hymenophyllaceae family display almost translucent fronds, bearing thickness of just a single cell.[3][4][5][6][7]

## Description

[edit]

Rhizome: The glabrescent (near hairless) rhizome forms a creeping, interlacing thread across various substrates, including larger ferns such as Dicksonia antarctica, rocks and fallen logs.

Leaves: Each frond consists of several dark-green pinnae encompassing multiple lamina, with toothed margins and a single vein.[3] Size can vary from 1.5 – 17 cm in length. H. peltatum is distinguished from otherwise similar relatives (such as H. cupressiforme) by the unique ‘apically winged’ foliage,[4] where branching only occurs on the apex side (i.e. toward the main stem), known as acroscopic branching.[4]

Sori occur (1-2) on the acroscopic side of the primary pinna. When mature, each sorus is attached by a small, peltate branch, hence the name H. peltatum.[5] The sorus is a funnel-shaped receptacle, housing numerous sporangia, each approximately 1-2mm long and 0.5-1mm wide.[4] The indusium forms a cleft of two-lips, which have entire margins protecting the developing sporangia.[4]

## Habitat and distribution

[edit]

While not as common as H. cupressiforme species, H. peltatum is widespread and known to occur in cool temperate to sub-tropical rainforests around the world, including Australia, New Zealand, South Africa and South America.[3] One of 19 Hymenophyllum species found in Australia, H. peltatum can be observed across Tasmanian alpine regions, Victoria, NSW, and rarely in Queensland.[3][4] Habitat includes wet, mossy banks, rocks and logs. It also occurs as an epiphyte on trees such as Nothofagus cunninghami and Atherosperma moschatum.[6]

## Nomenclature

[edit]

Hymenophyllaceae: displaying the thinnest fronds of any fern species,[7] hymen is derived from the Greek word for 'membrane', and phyllon meaning 'leaf'.[5] Another defining feature is the sorus structure, a two-flapped indusium which houses the sporangia in a protective receptacle, often clustered around a central axis.[5] Subgenus Hymenophyllum is defined by the toothed margins of each lamina within a frond.[5]

Peltatum: When mature, each sori is attached by a small, 'peltate' branch, hence the name H. peltatum which is derived from the Latin word peltatus, used to describe an organ attached by a central stalk.[5]

'Alpine' filmy fern: This particular species is generally observed 600m above sea level.

## Conservation values

[edit]

Warming temperatures, increased fire events and changes in land use could see reduced habitat potential for H.peltatum.

## Affinities

[edit]

Easily confused with H. cupressiforme, which has slightly larger fronds and pinnae are branched on both sides.[4]

## References

[edit]

1. ^ "Checklist of Ferns and Lycophytes of the World - Hymenophyllum peltatum (Poir.) Desv". World Ferns. Archived from the original on 2 September 2017. Retrieved 16 March 2020.
2. ^ "Hymenophyllum peltatum". NZ Flora. Retrieved 15 March 2020.
3. ^ a b c d e Duncan, Betty D; Isaac, Golda (1986). Ferns and allied plants. Carlton, Victoria: Melbourne University Press. pp. 81–89\. ISBN 0522842623.
4. ^ a b c d e f g h McMarthy, P, ed. (1998). Flora of Australia. Volume 48: Ferns, Gimnosperms and Allied Groups. Melbourne, Australia: ABRS. pp. 122–127.
5. ^ a b c d e f Wapstra, Mark; Wapstra, Annie; Wapstra, Hans (2010). Tasmanian plant names unravelled. Launceston, Tasmania: Fullers Bookshop Pty Ltd. p. 449\. ISBN 9780980472028.
6. ^ a b Jordan, G, ed. (2016). The'Key to Tasmanian Vascular Plants'. Australia: Australasian Plant Conservation: Journal of the Australian Network for Plant Conservation 25(1). p. 15.
7. ^ a b Willis, J, ed. (1975). Ferns of Victoria and Tasmania. Victoria, Australia: Field Naturalists Club of Victoria. pp. 5–7.

Taxon identifiers

Hymenophyllum peltatum|

* Wikidata: Q15604195
* Wikispecies: Hymenophyllum peltatum
* APDB: 212882
* APNI: 80317
* CoL: 3NKLD
* EUNIS: 150264
* FoAO2: Hymenophyllum peltatum
* GBIF: 7315537
* iNaturalist: 323518
* IPNI: 17124480-1
* NCBI: 638566
* NSWFlora: Hymenophyllum~peltatum
* NZOR: 63074cd8-718d-48c1-8500-6d6d85445482
* NZPCN: 846
* Observation.org: 447016
* Open Tree of Life: 141654
* Plant List: tro-26600465
* POWO: urn:lsid:ipni.org:names:17124480-1
* SANBI: 2176-4
* Tropicos: 26600465
* VicFlora: f8e4b6f7-e515-45cb-9ac0-8fdea3e96349
* WFO: wfo-0001107539

Trichomanes peltatum|

* Wikidata: Q38232767
* Wikispecies: Trichomanes peltatum
* APDB: 221622
* APNI: 205791
* GBIF: 5532911
* iNaturalist: 406659
* IPNI: 17231540-1
* NZOR: 87c47013-0e3a-4c1c-b51f-1e76647e8c59
* POWO: urn:lsid:ipni.org:names:17231540-1
* Tropicos: 26603024
* WFO: wfo-0001109764