A Phylogenetic Study of Perideridia (Apiaceae) Based on Nuclear Ribosomal DNA ITS Sequences

Abstract

Abstract A phylogenetic study of the genus Perideridia (Apiaceae; tribe Oenantheae) was conducted to elucidate its circumscription, infrageneric relationships, and patterns in the evolution of available morphological, anatomical, and cytological characters. Nuclear rDNA ITS sequences were procured from 84 accessions of Perideridia, representing all 14 of its species and four of its six subspecies, and five outgroup taxa, and analyzed using maximum parsimony, maximum likelihood, and Bayesian inference methods. The trees recovered by each of these optimality criteria were congruent and generally quite robust. Upon the removal of the eastern Asian Perideridia neurophylla, previously referable to Pterygopleurum neurophyllum, the genus Perideridia is monophyletic and exclusively North American in distribution. Three major clades within Perideridia are inferred; the midwestern U.S. Perideridia americana is likely sister to all other species. With the exceptions of Perideridia lemmonii and P. bolanderi (where ea...