CYSTOPTERIS FRAGILIS SUBSP. HUTERI, A TAXON NEW TO THEBRITISH ISLES AND RELATED TAXA IN THE CYSTOPTERIS FRAGILIS COMPLEX: CYSTOPTERIDACEAE (POLYPODIOPSIDA)

摘要

A taxon in the Cystopteris fragilis (L.) Bernh. complex that occurs in Britain appears up to now to have been overlooked there. It is proposed that this fern, which was recently rediscovered in Snowdonia, North Wales, should be referred to a subspecies of C. fragilis, namely subspecies huteri (Hausm. ex Milde) C. Prada & Salvo, that occurs in mainland Europe, but had not previously been recognised in the British Isles. The Snowdonia fern is distinct in its morphology from other British taxa in the C. fragilis complex and is described here together with its historic records and present distribution, updated from information given in an earlier paper in Watsonia (Tennant, 2010), and its relationship to affiliated taxa is discussed.