Molecular phylogeny of the genus Fissidens (Fissidentaceae, Bryophyta) and a refinement of the infrageneric classification.

The genus Fissidens (ca. 440 spp.) is one of the phylogenetically poorly studied groups of mosses (Bryophyta). While various classifications of this genus have been proposed, no attempt at a classification of the genus based on combined molecular and morphological evidence has been made. Here, we present for the first time a comprehensive phylogenetic tree consisting of 50 representatives of Fissidens, reconstructed using sequence data from chloroplast rbcL and rps4 genes. Ancestral state reconstructions provide three clear apomorphies within Fissidens: peristome teeth, limbidium and chromosome number. Based on the phylogeny and morphological reassessment, we recognize three subgenera, Pachyfissidens, Neoamblyothallia, and Fissidens. Subgenus Neoamblyothallia consists of two sections: Neoamblyothallia and Crispidium. Subgenus Fissidens consists of five sections: Fissidens, Polypodiopsis, Aloma, Areofissidens, and Semilimbidium. High diversity of the most derived sect. Semilimbidium in the tropics suggests that the evolutionary history of the genus is through adaptation and diversification in tropical regions.