Asplenium trichomanes subsp.
quadrivalens D.E. Mey., a Maidenhair Spleenwort
Account Summary
Native, probably frequent but under-recorded at subspecific level. Circumpolar southern-temperate.
1974; Hackney, P.; Boho Caves.
July and August.
Despite the Asplenium trichomanes maps in the New Atlas plotting only subsp. quadrivalens for Ireland, the diploid calcifuge subsp. trichomanes has been recorded from nine VCs, including in N Ireland, Cos Armagh and Down (H37 & H38). Adjacent VCs to Fermanagh where subsp. trichomanes has also been recorded are Co Sligo and both E & W Donegal (H28, H34 and H35). Subsp. pachyrachis (H. Christ) Lovis & Reichst. has not yet been discovered anywhere on the island of Ireland (Matthew Jebb, pers. comm., 2010).
Having said all that, it is believed that the vast majority of the plants of A. trichomanes in Ireland belong to subsp. quadrivalens, although so far there are only eleven records of this subspecies from ten tetrads in Fermanagh, nine of them the work of Paul Hackney. Vouchers exist for Hackney's records in BEL.
While subsp. quadrivalens almost always frequents limestone terrain, the main habitat of subsp. trichomanes is on hard, acidic volcanic or metamorphic rocks, making it unlikely to occur in Fermanagh, although it is possible that the third taxon, subsp. pachyrachis could occur with us on steep limestone rock faces. Only time and plenty of further careful recording will tell whether or not Ireland supports all three A. trichomanes subspecies, and, if it does, their comparative frequency.
Growth form and preferred habitats
Maidenhair Spleenwort is a small, distinctive, evergreen perennial species that colonises crevices on upland limestone outcrops and cliffs. In lowland areas it frequently occurs on the mortar in walls. It is most abundant and luxuriant when the habitat offers high humidity and it becomes distinctly stunted in drier, more exposed sites.
Taxonomy
Asplenium trichomanes really consists of a complex polyploid series of forms, within which a simplified account segregates three ecologically and morphologically recognisable subspecies in Britain and Ireland. All of the Fermanagh records almost certainly refer to by far the most common of the three forms, the tetraploid A. trichomanes subsp. quadrivalens D.E. Mey. (but see the separate account below). Essentially this is a calcicole subspecies, but to a surprising degree it can tolerate habitats with soils having very little calcium present (Jermy & Camus 1991; Jonsell et al. 2000).
Fermanagh occurrence
In Fermanagh, this fern species has been recorded in 181 tetrads, 34.3% of those in the VC. Eight scattered tetrads have pre-1976 records only. It is widespread throughout the county, but is especially frequent in crevices on upland limestone outcrops and cliffs. It also occurs less commonly on sandstone scarps in the Lough Navar area which have been dolomitized by seepage of water rich in both calcium and magnesium carbonates derived from overlying base-rich mica-schists.
In lowland areas of Fermanagh, A. trichomanes is restricted to man-made habitats such as the lime-rich mortar in old walls, bridges, basement areas around older houses, walled gardens and the like.
British and Irish occurrence
A. trichomanes subsp. quadrivalens is common throughout Britain and Ireland, but it is perhaps slightly less frequent in Ireland than in Britain (Jermy & Camus 1991). Until the publication of the New Atlas in 2002 there were insufficient data to permit the subspecies to be mapped separately. The New Atlas maps and those in the New Fern Atlas (Wardlaw & Leonard 2005), both suggest that only subsp. quadrivalens occurs in Ireland. The other two subspecies are very much less common in Britain, and subsp. pachyrachis (H. Christ) Lovis & Reichst. is recorded from just eight hectads in England.
European and world occurrence
The collective species, A. trichomanes is common and widespread in W and C Europe, thinning out to both north and south although reaching well within the Arctic Circle. However, it is currently declining in Scandinavian countries (Jalas & Suominen 1972, Map 81; Jonsell et al. 2000). In the widest sense, A. trichomanes is a circumpolar southern-temperate species (Hultén 1962, Map 130; Preston & Hill 1997), but is also very well distributed around the southern hemisphere, being present in S Africa, C and S America, New Guinea, S Australia and New Zealand (Hultén 1962, p. 138; Hultén & Fries 1986, Map 41).
Names
'Asplenium' is derived from the Greek 'a' meaning 'not' and 'splen', 'splene' or 'splenon' referring to the spleen, alluding to the supposed medicinal properties of the fern genus. The herbal medicinal use is also invoked by the English common name applied to the genus, ‘Spleenwort’ (Hyam & Pankhurst 1995).
The Latin specific epithet ‘trichomanes’ is the genus name given to Maidenhair Spleenwort by Theophrastus, the ancient Roman doctor. ‘Trichomanes’ is Greek and it refers to a thin hair or a bristle (Johnson & Smith 1946). After the green pinnae die and drop off the black or deep brown stipe of the frond, the bare remainder adds to the short, dense, wiry tuft of old stipes attached to the plant. Certainly, no female would be flattered to have the hair on her head compared to the wiry tuft of a Maidenhair Spleenwort plant. It follows that ‘Maidenhair’ must refer to hair located elsewhere on the body, and it is not too difficult to imagine where.
Uses
A tea made with the fronds was described as ‘ sweet, mucilaginous and expectorant’ and was used in herbal medicine to treat lung disorders. It was also considered a laxative (Grieve 1931, page 303).
Threats
None.