Hymenophyllum peltatum
| 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 – 17cm 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]
- ^ "Checklist of Ferns and Lycophytes of the World - Hymenophyllum peltatum (Poir.) Desv". World Ferns. Retrieved 16 March 2020.
- ^ "Hymenophyllum peltatum". NZ Flora. Retrieved 15 March 2020.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ a b Willis, J, ed. (1975). Ferns of Victoria and Tasmania. Victoria, Australia: Field Naturalists Club of Victoria. pp. 5–7.