The bristle fern has thin, very dry, egg–shaped leaves that measure about 4 to 16 inches long. The leaves are attached to creeping, wiry stems. As the plant matures, structures at the margins (edges) of the leaves harden to form a bristle (point), thus giving the plant its common name.
Ferns reproduce by dispersing spores (tiny, usually onecelled reproductive bodies) instead of seeds. The spore cases, called sporangia (pronounced spor–AN–ja), are located in pockets on the margins of the leaves.
Botanists (people specializing in the study of plants) believe the green spores of the bristle fern are dispersed by water (rain and other precipitation) rather than wind.
Habitat and current distribution
The bristle fern is considered vulnerable throughout most of its range. In France and Portugal, it is endangered. The plant is faring better in Ireland and Spain, where it is listed as rare.
The bristle fern needs a constant source of flowing water. Because the plant has very thin leaves, it is most often found in dark crevices and gullies in deep, narrow, wooded valleys in areas where rainfall is plentiful. It is also found growing in sandstone close to streams and waterfalls.
History and conservation measures
In the wild, the bristle fern is threatened throughout its range by deforestation (clearing away trees from a forest). In a number of areas in northern Spain, it is also threatened by spreading eucalyptus plantations.
Although the bristle fern is protected under the Bern Convention and the European Union Habitats Directive, no other conservation measures have currently been established.