Chloroplast DNA variation and the phylogeny of Asplenium sect. Hymenasplenium (Aspleniaceae) in the New World tropics

Asplenium sect. Hymenasplenium is a well-defined group in Aspleniaceae, distinguished by several morphological and cytological characters. However, interspecific relationships in the section were not clear. In this paper, we report the phylogenetic relationships of 9 Neotropical species of sect. Hymenasplenium determined by chloroplast DNA restriction site variation analyses. From the obtained phylogenetic tree, two major clades: one with A. obtusifolium, A. riparium, A. volubile and A. repandulum and another with A. delitescens, A. ortegae, A. purpurascens, A. laetum and A. hoffmannii were recognized. Asplenium delitescens was shown to have a polyphyletic origin. It was also shown that the epiphytic habit evolved only once in the New World species of sect. Hymenasplenium.