Phylogeny and classification of the Cuban species of Elaphoglossum (Dryopteridaceae), with description of Elaphoglossum sect. Wrightiana sect. nov.

Although a worldwide phylogeny of the bolbitidoid fern genus Elaphoglossum is now available, little is known about the phylogenetic position of the 34 Cuban species. We performed a phylogenetic analysis of a chloroplast DNA dataset for atps-rbcL (including a fragment of the gene atps), rps4-trnS, and trnL-trnF. The dataset included 79 new sequences of Elaphoglossum (67 from Cuba) and 299 GenBank sequences of Elaphoglossum and its most closely related outgroups, the bolbitidoid genera Arthrobotrya, Bolbitis, Lomagramma, Mickelia, and Teratophyllum. We obtained a well-resolved phylogeny including the seven main lineages recovered in previous phylogenetic studies of Elaphoglossum. The Cuban endemic E. wrightii was found to be an early diverging lineage of Elaphoglossum, not a member of E. sect. Squamipedia where it was previously classified. We propose a new section for this species: E. sect. Wrightiana. The early diverging position of E. wrightii is of particular interest because the species is a root climber (i.e., climbing from the soil on the lower portions of tree trunks and not losing its connection with the soil), a growth habit it shares with its closest bolbitidoid outgroup genera. This suggests that holoepiphytism evolved later in Elaphoglossum, and the primary hemiepiphytism of E. amygdalifolium, which is sister to the rest of the genus, was derived independently from ancestors that were root climbers. Based on our phylogenetic analysis and morphological investigations, the species of Cuban Elaphoglossum were found to occur in E. sects. Elaphoglossum, Lepidoglossa, Polytrichia, Setosa, and Squamipedia.