Molecular phylogeny of Daucus (Apiaceae): Evidence from nuclear ribosomal DNA ITS sequences

Abstract

The Apiaceae genus Daucus consists of approximately 25 species (including carrots) which are characterized by the presence of bracts in pedunculate umbels, dorsally compressed mericarps, hairs on primary ridges, and uniseriately arranged spines on the secondary ridges of the fruit. Taxonomically, Daucus has been considered to be one of the most problematic genera in the Apiaceae due to the highly variable fruit morphology. Despite taxonomic controversy and economic importance of the genus, no rigorously constructed estimate of phylogenetic relationships exists. To examine generic limit and relationships among species of Daucus and its putatively related taxa, phylogenetic analyses of characters derived from nuclear ribosomal DNA ITS sequences were conducted. Two major clades emerged within Daucus, but neither of them have been previously recognized using morphological characters. The phylogeny also provides taxonomic status of recently reported new species of Daucus, D. arcanus and D. conchitae.