Maidenhair fern (Adiantum capillus-veneris)

Kingdom	Plantae
Phylum	Tracheophyta
Class	Filicopsida
Order	Polypodiales
Family	Adiantaceae
Genus	Adiantum (1)
Size	Height: 30 – 45 cm (2)

The maidenhair fern has yet to be classified by the IUCN.

A delicate-looking, drooping fern with distinctive fan-shaped leaf segments, the maidenhair fern (Adiantum capillus-veneris) possesses many clustered fronds (large, divided leaves) on wiry black stems (2) (3) (4) (5). It spreads by means of short, creeping rhizomes, covered in small brown scales, which sometimes appear reddish-brown or golden (2) (4) (5) (6) (7) (8). The fronds are arching and hairless, occasionally with a bluish-green or waxy (glaucous) tinge to the normally pale green leaves, which are pinnate, with individual leaflets often lobed or toothed along the margins (3) (4) (6) (7) (8).

The genus name of the maidenhair fern, Adiantum, is derived from the Greek word ‘Adiantos’ - meaning ‘unwetted’ - as the leaves of the fern repel water, while the species name is taken from the Latin words ‘capillus’ and ‘veneris’, meaning ‘hair of Venus’, giving this plant its alternative common name, the Venus maidenhair fern (2) (9).

The maidenhair fern is widespread throughout tropical and temperate regions of the world, and is found in North, South and Central America, Mexico, Canada (British Columbia), Europe, Asia, Africa and Australia (2) (4) (5) (7) (8) (9).

Requiring fairly warm and humid conditions, the maidenhair fern is found in shaded, moist areas where it typically grows on rock faces and in crevices of cliffs, on banks and ledges along streams and rivers, or close to natural hot springs (3) (5) (6) (7) (8) (9).

The maidenhair fern reproduces both vegetatively and from spores. It sporulates (produces and disperses spores) during the spring and summer (7), with the spores of the maidenhair fern produced and contained in structures called sporangia, which are grouped into clusters known as ‘sori’, on the outer edges of the leaflet’s lower surface. The edges of the leaves fold over to form a crescent-shaped protective flap, called an ‘indusium’ (2) (4) (5) (6) (7) (8).   

Although the maidenhair fern is widespread worldwide, in Australia and Canada it is only known from single sites, where it is threatened by habitat loss and degradation due to human development. Additional threats include collection, disturbance and invasive species (4) (8).

Similar problems may threaten other populations of the maidenhair fern around the world; however, as yet no quantitative research has been carried out. 

In Australia, the maidenhair fern is listed as a threatened taxon on Schedule 2 of the Flora and Fauna Guarantee Act 1988 (4), while in Canada it is a red-listed species in British Colombia, where it is considered Endangered (8).

In Canada, the maidenhair fern occurs on privately owned land, and, although it is not currently protected, it is hoped that a single-species recovery strategy will soon be implemented (5). Elsewhere, there are no known conservation measures in place for the maidenhair fern. 

To find out more about the recovery strategy for the maidenhair fern in Canada, see:

• Recovery strategy for the southern maiden-hair fern (Adiantum capillus-veneris) in British Columbia:
  http://www.env.gov.bc.ca/wld/documents/recovery/rcvrystrat/southern_maidenhairfern_rcvry_strat_281107.pdf

To find out more about plants and fungi, see:

• Royal Botanic Gardens, Kew:
  http://www.kew.org/

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

• Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
• Pinnate: in plants, a compound leaf where the leaflets (individual ‘leaves’) are found on either side of the central stalk.
• Rhizome: thickened, branching, creeping storage stem. Although most rhizomes grow laterally just along or slightly below the soil's surface, some grow several inches deep. Roots grow from the underside of the rhizome, and during the growing season new growth sprouts from buds along the top. A familiar rhizome is the ginger used in cooking.
• Spores: microscopic particles involved in both dispersal and reproduction. They comprise a single or group of unspecialised cells and do not contain an embryo, as do seeds.
• Vegetative reproduction: type of asexual reproduction (reproduction without recombination of genetic material) that results in the propagation of plants using only the vegetative tissues such as leaves or stems. The resulting plant is genetically identical to the original plant. A well-known example of this is the reproduction of strawberry plants from ‘runners’.

1. UNEP-WCMC (November, 2010)
   http://www.unep-wcmc.org/
2. Missouri Botanical Garden (November, 2010)
   http://www.mobot.org/
3. Ferns in Britain and Ireland: A guide to ferns, horsetails, clubmosses and quillworts (November, 2010)
   http://www.ferns.rogergolding.co.uk/ferngenus/adiantum/capillusveneris.html
4. Department of Sustainability and Environment. (2003) Flora and Fauna Guarantee Action Statement: Dainty Maidenhair (Adiantum capillus-veneris). Department of Sustainability and Environment, Victoria (Australia). Available at:
   http://www.dse.vic.gov.au/CA256F310024B628/0/39EDE2F4AB8D7634CA257068000DBA42/$File/016+Dainty+Maidenhair+1992.pdf
5. Southern Maidenhair Fern Recovery Team. (2007) Recovery Strategy for the Southern Maidenhair Fern (Adiantum capillus-veneris) in British Columbia. British Colombia Ministry of Environment, Victoria, BC.
6. Royal Botanic Gardens, Kew (November, 2010)
   http://www.kew.org/
7. eFloras: Floras of North America (November, 2010)
   http://www.efloras.org/
8. COSEWIC. (2000) COSEWIC Assessment and Update Status Report on the Southern Maidenhair Fern Adiantum capillus-venerisin Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa. Available at:
   http://dsp-psd.pwgsc.gc.ca/Collection/CW69-14-87-2002E.pdf
9. The Nature Conservancy (November, 2010)
   http://www.nature.org/