A Revision of Caribbean Adiantopsis

by Barker, Michael Shane

Adiantopsis is a tropical cheilanthoid fern genus that unlike other cheilanthoid genera, is unstudied. The present work evaluated the taxonomy and relationships among Caribbean Adiantopsis . A total of 136 characters were examined on approximately 500 herbarium specimens. This study identified nine Caribbean Adiantopsis species, of which three are newly discovered. Additionally, an intriguing pattern of morphological and reticulate evolution was revealed by the analyses. Adiantopsis consists of three different lamina morphologies; palmate, pedate, and pinnate. The two pedate taxa are hypothesized to be fertile allotetraploid derivatives of the single palmate A. radiata and two different pinnate taxa. In this regard they parallel the origin of the South American A. × austropedata . Thus, it appears that the pedate lamina morphologies in Adiantopsis are convergent, having originated multiple times via hybridization. This study provides testable hypotheses of morphological and reticulate evolution in the genus and presents a novel view of Caribbean Adiantopsis .