A Phylogenetic Analysis of the Genus Ophioglossum S.S. (Ophioglossaceae)

Indianapolis, IN

Cryptic species are lineages of organisms that look similar but are evolutionarily distinct. Identifying cryptic species can help address questions about extant species richness and evolutionary relationships. Some species within the genus Ophioglossum s.s. (Ophioglossaceae) are examples of cryptic species. Using chloroplast DNA sequences from five loci, I examined relationships among 38 accessions representing 17 species to determine whether morphologic species are real evolutionary units. I generated two phylogenetic trees, one using maximum likelihood (ML) and the other using maximum parsimony (MP), to estimate evolutionary relationships within Ophioglossum s.s. Three main species clades emerged in the ML and MP analyses, two of which were well supported. Across the three clades, four morphologic species were not monophyletic and contained multiple, potentially cryptic lineages: O. crotalophoriodes, O. nudicaule, O. vulgatum, and O. lusitanicum. Based on these results, morphological features alone may not provide enough reliable information for the recognition of species.