The generic position of Annesorhiza filicaulis Eckl. & Zeyh. (Apiaceae)

A study of the fruit structure of Annesorhiza filicaulis Eckl. & Zeyh. has shown that only the four commissural ribs are expanded, resulting in a fruit wing configuration characteristic of the genus Peucedanum. Hysteranthous or seasonal leaves, as present in A. filicaulis, are not unique to Annesorhiza but are also encountered in Chamarea Eckl. & Zeyh. and in Peucedanum sulcatum Sond. and related species. The correct generic delimitation of Peucedanum (one or several genera) is one of the last challenges in the alpha taxonomy of southern African Apiaceae, and A. filicaulis complicates the matter even further. Nevertheless, A. filicaulis is clearly a misfit in Annesorhiza and should be included in future studies of Peucedanum sensu lato, even though the latter may prove not to be monophyletic. Annesorhiza filicaulis is formally transferred to Peucedanum, and the correct nomenclature, typification and known geographical distribution of this poorly known species is presented.