The genus Plagiochila (Dumort.) Dumort.: (Plagiochilaceae, Hepaticophytina) in Madeira Archipelago -: Molecular relationships, ecology, and biogeographic affinities

Plagiochila is one of the most frequent bryophyte genera in Madeira, inhabiting almost all habitats of the Madeiran laurel forest (Laurisilva). Results on the biodiversity, ecology and molecular relationships based on nuclear ribosomal ITS1 and ITS2 sequences of all Plagiochila species referred to Madeira Archipelago are summarized with the aims to provide (i) a first molecular confirmation of a species inventory of a bryophyte genus in a specific geographic region and (ii) a bryophyte example for displaying biogeographic affinities of the Madeiran laurel forest. The molecular analyses confirm the presence of nine species in Madeira, which belong to four sections: Plagiochila sect. Arrectae, sect. Rutilantes, sect. Vagae and sect. Plagiochila. Section Arrectae is represented in Madeira by five species, A bifaria, P. punctala, P. retrorsa, P. spinulosa, and A stricta. Section Rutilantes is represented by P. exigua and the Macaronesian endemic P. maderensis, which is reported for the first time to Canary Is. The sections Vague and Plagiochila are represented by a single species each, P. virginica and P. porelloides, respectively. The molecular data indicate strong biogeographic affinities of the Madeiran Plagiochila flora with Central and northern South America, and to a lesser extent with Africa and Continental Europe. The environmental conditions found in Madeira Island, especially habitat stability and the stable climate in the laurel forest, may have favored the development of populations of Plagiochila species from neotropical sections.