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Australian ferns & fern allies |
[ see also: Conservation Status of Norfolk Island Ferns ]
47 taxa of ferns and their allies are known to occur on Norfolk Island. Four, possibly five are introduced; of these two as weeds, the remainder as garden plants that may be naturalized. A number of the more striking native species are grown in local gardens.
There are a further 13 species that have been recorded from the island in the past, but are excluded from the current flora for a variety of reasons, including the absence of supporting specimens, misidentification of specimens, misinterpretation of species, and suspect or erroneous specimen label data.
The total species count is relatively small for a locality with suitable habitat at this latitude in this geopgraphic region and reflects the fact the the available land area is only c. 5 x 8 km. Based on consideration of habitat and the floras of surrounding geopgraphic region, perhaps as many as an additional 6 genera and 18 species might reasonably be expected, but thorough searching over more than one and a half centuries has not found them. Our knowledge of today's pteridophyte flora of Norfolk Island can be considered good, and for all intents and purposes, complete.
Of the taxa known from Norfolk Island, 7 (16% of the flora) are endemic and are known from nowhere else; a single species is known from only Norfolk and Lord Howe Islands. There are 30 taxa shared with Australia, 24 with New Zealand, 18 each with Lord Howe Island and New Caledonia, and 21 with various islands in the South Pacific. 25 Norfolk Island species (including 7 endemics) are not on Lord Howe Island and 40 Lord Howe Island species (including 22 endemics) are not on Norfolk Island. Seven taxa are widespread and are known from all these regions.
Aus = Australia; NI = Norfolk Island; LHI = Lord Howe Island; NC = New Caledonia; NZ = New Zealand; Pac = South Pacific
| Family | Species | Aus | NI | LHI | NC | NZ | Pac | Notes |
|---|---|---|---|---|---|---|---|---|
| Lycopodiaceae | Lycopodiella cernua | Aus | NI | LHI | NC | NZ | Pac | Native; possible recent introduction |
| Psilotaceae | Psilotum nudum | Aus | NI | LHI | NC | NZ | Pac | Native; occasional to common |
| Psilotaceae | Tmesipteris norfolkensis | NI | Endemic; scattered on tree ferns | |||||
| Selaginellaceae | Selaginella kraussiana | Aus | NI | NZ | Garden escape, weed | |||
| Adiantaceae | Adiantum diaphanum | Aus | NI | NZ | Pac | Native; common | ||
| Adiantaceae | Adiantum pubescens | NI | LHI | NZ | Native; common | |||
| Adiantaceae | Cheilanathes distans | Aus | NI | LHI | NC | NZ | Native; frequent | |
| Adiantaceae | Cheilanathes sieberi | Aus | NI | LHI | Native; rare | |||
| Aspleniaceae | Asplenium australasicum f. australasicum |
Aus | NI | LHI | NC | Pac | Native; becoming uncommon | |
| Aspleniaceae | Asplenium australasicum f. robinsonii |
Aus | NI | LHI | Known only in cultivation | |||
| Aspleniaceae | Asplenium difforme | Aus | NI | Native; occasional to fairly common | ||||
| Aspleniaceae | Asplenium dimorphum | NI | Endemic; quite common | |||||
| Aspleniaceae | Asplenium polyodon | Aus | NI | LHI | NC | NZ | Pac | Native; reasonably common |
| Athyriaceae | Deparia petersenii subsp. congrua |
Aus | NI | NC | NZ | Pac | Native; rare | |
| Athyriaceae | Diplazium assimile | Aus | NI | Native; frequent | ||||
| Athyriaceae | Diplazium australe | Aus | NI | NZ | Native; uncommon | |||
| Azollaceae | Azolla pinnata | Aus | NI | NC | NZ | Pac | Introduced; water weed | |
| Blechnaceae | Blechnum norfolkianum | NI | NZ | Pac | Native; not common | |||
| Blechnaceae | Doodia media | Aus | NI | NC | Native; common | |||
| Cyatheaceae | Cyathea australis subsp. norfolkensis |
NI | Endemic; not common | |||||
| Cyatheaceae | Cyathea brownii | NI | Endemic; common | |||||
| Dennstaedtiaceae | Histiopteris incisa | Aus | NI | LHI | NC | NZ | Pac | Native; widespread |
| Dennstaedtiaceae | Hypolepis dicksonioides | NI | NZ | Pac | Native; rare | |||
| Dennstaedtiaceae | Hypolepis tenuifolia | Aus | NI | NC | Pac | Native; rare | ||
| Dennstaedtiaceae | Pteridium esculentum | Aus | NI | NC | NZ | Pac | Native; common | |
| Dryopteridaceae | Arachniodes aristata | Aus | NI | LHI | NC | NZ | Pac | Native; very common |
| Dryopteridaceae | Lastreopsis calantha | NI | Endemic; fairly common | |||||
| Gleicheniaceae | Dicranopteris linearis | Aus | NI | NC | NZ | Pac | Introduced? | |
| Hymenophyllaceae | Cephalomanes bauerianum | NI | LHI | Native; endemic to NI, LHI | ||||
| Hymenophyllaceae | Crepidomanes endlicherianum | NI | NZ | Native | ||||
| Hymenophyllaceae | Crepidomanes saxifragoides | Aus | NI | NC | Pac | Native; localized | ||
| Marratiaceae | Marattia salicina | NI | NZ | Native; vulnerable | ||||
| Oleandraceae | Nephrolepis cordifolia | Aus | NI | LHI | NC | Nz | Pac | Native; localized |
| Oleandraceae | Arthropteris tenella | Aus | NI | LHI | NZ | Native; common | ||
| Ophioglossaceae | Ophioglossum petiolatum | Aus | NI | LHI | NC | NZ | Native | |
| Polypodiaceae | Microsorum pustulatum subsp. pustulatum |
Aus | NI | NZ | Native; locally abundant | |||
| Polypodiaceae | Platycerium bifurcatum var. bifurcatum |
Aus | NI | LHI | Introduced, cultivated ornamental | |||
| Polypodiaceae | Pyrrosia confluens | Aus | NI | LHI | NC | Pac | Native; common | |
| Pteridaceae | Pteris kingiana | NI | Endemic; locally common | |||||
| Pteridaceae | Pteris tremula | Aus | NI | LHI | NZ | Pac | Native; locally common | |
| Pteridaceae | Pteris vittata | Aus | NI | ?NZ | Pac | Most likely introduced; naturalized | ||
| Pteridaceae | Pteris zahlbruchneriana | NI | Endemic | |||||
| Salviniaceae | Salvinia molesta | Aus | NI | NZ | Pac | Introduced; water weed | ||
| Thelypteridaceae | Christella dentata | Aus | NI | LHI | NC | NZ | Pac | Native; fairly common |
| Thelypteridaceae | Christella parasitica | Aus | NI | LHI | NC | Pac | Native; uncommon | |
| Thelypteridaceae | Macrothelypteris torresiana | Aus | NI | Pac | Native; rare | |||
| Vittariaceae | Vittaria elongata | Aus | NI | NC | Pac | Native; not common | ||
| Doubtful records | ||||||||
| Lycopodiaceae | Lycopodium deuterodensum | Aus | No known specimens | |||||
| Adiantaceae | Adiantum fulvum | Based on mislabelled specimen | ||||||
| Adiantaceae | Pellaea rotundifolia | No known specimens | ||||||
| Aspleniaceae | Asplenium oblongifolium | NZ | Based on a mislabelled specimen | |||||
| Blechnaceae | Blechnum discolor | NZ | Based on a misidentfication | |||||
| Blechnaceae | Doodia aspera | Aus | NI | NZ | Pac | confirmation needed; no known specimens | ||
| Blechnaceae | Doodia caudata | Aus | No known specimens | |||||
| Davalliaceae | Davallia solida var. pyxidata |
Aus | NZ | Based on a mislabelled specimen | ||||
| Dennstaedtiaceae | Microlepia speluncae | Aus | Based on mislabelled specimens | |||||
| Dryopteridaceae | Lastreopsis microsora | Aus | Based on misinterpretation | |||||
| Dryopteridaceae | Rumohra adiantiformis | Aus | NZ | Based on a mislabelled specimen | ||||
| Lindsaeaceae | Lindsaea linearis | Aus | NC | NZ | No known specimens | |||
| Lindsaeaceae | Lindsaea linearis | Aus | NC | NZ | No known specimens | |||
| Lygodiaceae | Lygodium japonicum | No known specimens |
The composition of the Norfolk Island flora reflects its historical and geopgraphical relationships with surrounding regions, in particular, Australia, New Zealand, New Caledonia and the islands of the Pacific, and relatively nearby LOrd Howe Island. It is basically a reduced subtropic oceanic flora with zero endemicity at the generic level but a somewhat surprising 16% at the species level, 7 out of a flora of 43. For comparison, Lord Howe Island also has 0% endemicity at the generic level and 38% endemicity at the species level, 22 of a flora of 58 taxa. Many of the endemic taxa are close vicariant relatives to more common species from neighbouring regions.
* = Norfolk Island endemic.
* = Lord Howe Island endemic.
* = introduced or possibly so.
After two and a quarter centuries of european inhabitation, the native vegetation of Norfolk Island has been irrevocably altered, intentionally with land clrearing for civil and domestic construction, earthworks and agriculture, and unintentionally with the introduction of weeds and feral animal pests. Estimates of remaining undisturbed land areas range from 2% to 5% and and island once forested and largely free of grass species is now dominated by pasture. Available fern habitats have contracted and many of the less hardy species are now restriced to scattered and small patches within the National Park and other reserves. Nevertheless, it is is possible to visit localities where ferns have been collected in the past and find many of the species.
Green, P.S. 1994. Pteridophyta. In Wilson, A.J.G. (ed.) Flora of Australia volume 49, Oceanic Islands 1. Australian Government Publishing Service, Canberra.
Braggins, J. 1996. Report on the conservation status of Norfolk Island ferns. Unpublished report prepared for the Australian Nature Conservation Agency, Norfolk Island. Auckland Uniservices Ltd, New Zealand.
McCarthy, P.M. (ed.) 1998. Flora of Australia volume 48, Ferns, Gymnosperns and Alied Groups. ABRS/CSIRO Publishing, Australia.