Taxonomic uncertainty and a continental conundrum: P olypodium macaronesicum reassessed

Data from the chloroplast trn L ‐ F region are used to test the delimitation of putative diploid species in the P olypodium cambricum aggregate. In particular, we investigate the distinctiveness of the M acaronesian P olypodium macaronesicum , P . azoricum and the continental P . cambricum , investigate molecular diversity patterns within Macaronesia and establish the identity of putative P . macaronesicum material collected from an area in southern S pain, where it co‐occurs with other M acaronesian elements. The analysis supports the distinction of M acaronesian and continental plants, with accessions from M acaronesia resolved as monophyletic. Greater haplotype diversity was found in M acaronesia than on the continent. All Macaronesian haplotypes were restricted to a single archipelago and were resolved into archipelago groupings in statistical parsimony analysis, suggesting limited dispersal between archipelagos. Morphological traits distinguish A zorean plants, but there are no clear morphological traits to distinguish M adeiran and C anarian plants. The recognition of P . macaronesicum as a distinct taxon is proposed, with two subspecies, one A zorean and one M adeiran– C anarian. Material from southern S pain referred to P . macaronesicum is shown to exhibit the A zorean haplotype, consistent with its morphology. This would represent a novel relationship for the flora of this continental M acaronesian enclave area if the occurrence of this taxon – collected only once in the region – is confirmed. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society , 2014, 174 , 449–460.