Taxonomic review on the African Umbelliferous genus Agrocharis: Inferences based on molecular data

Abstract

The taxonomic position of umbel genus Agrocharis, endemic to tropical Africa, was reviewed on the basis of molecular phylogenies derived from sequences of nuclear ribosomal DNA internal transcribed spacer (ITS) regions. The ITS sequence-derived phylogeny indicates that Agrocharis is monophyletic and is closely related to a clade comprising Daucus species: African (D. bicolor and D. durieua), Australian (D. glochidiatus), and American (D. pusillus and D. montanus). This phylogeny provides evidence that characters based upon the fruit's secondary spines show a high degree of variation within the genus Agrocharis, and thus these characters are only of limited value for delimiting the species boundary within the genus. The larger and more variable shapes of the secondary spines are considered to have evolved independently in these spiny-fruited umbel plants as an adaptation to locally changing environmental conditions for fruit dispersal.