Dryopteris filix-mas × D. affinis
(D. × complexa Fraser-Jenk.), a Male-fern hybrid
Account Summary
Very rare, but easily overlooked and very probably under-recorded.
1989; Tickner, M.; Stony Islands, Lower Lough Erne.
This deciduous rhizomatous hybrid is under-recorded throughout Britain and Ireland, but it usually occurs on damp, acidic soils in sheltered woodland, ditches, hedgerows and coniferous forest tracks, usually in lowland areas, and especially where the habitat has been disturbed. Plants may occur either as scattered individuals or in small clumps, with or without the presence of one or both of the parent species. Unfortunately, the intermediate hybrid is fully fertile and back-crossing is prevalent producing a swarm of variation that very greatly complicates identification of all three taxa. Since D. affinis (Scaly Male-fern) in particular is highly variable in any case, this makes a bad situation even worse. As Botanical Society of Britain and Ireland appointed joint-Vice-county Recorders for Fermanagh, Robert Northridge and myself (Ralph Forbes) have been present when even the greatest fern experts in Britain could not agree on the identity of these hybrid plants, for instance on the floor of the Cladagh River Glen!
Fermanagh occurrence
There are just eleven records, therefore, in the Fermanagh Flora Database, occurring in nine tetrads. The majority of them were made by Matthew Tickner of the RSPB when he was surveying the flora of small islands in Lower Lough Erne in summer 1989. The seven additional islands on which he claimed D. × complexa grew were as follows: Bingham's Rock, Coghran's, Gravelly, Inishmakill, Inishturk, Sam's and 'Stone Park West'. During a BSBI field meeting on 24 August 2004, the visiting English botanist Ken Trewen added a further three records with sites listed as follows: woodland in Correl Glen NR, determined by KT; scrub covered scarp on S side of Glencreawan Lough, determined by KT; woods beside Lower Lough Erne below the Cliffs of Magho, determined by KT.