A Taxonomic Revision of the Annesorhiza triternata Group (Apiaceae, Apioideae): The Transfer of Peucedanum triternatum and P. filicaule and the Description of Five New Species

A taxonomic revision of the Annesorhiza triternata group is presented. The group is composed of seven species all endemic to the Cape Floristic Region of South Africa. Two of the species had previously been assigned to the genus Peucedanum, as P.filicauk and P. triternatum, based on the marginally winged and dorsally ribbed homomericarpic fruits. They are here transferred to the genus Annesorhiza based on the periodically replaced fleshy roots, hysteranthous leaves, and fruits that have an oblong, more or less isodiametric body, a narrow commissure, and druse crystals scattered throughout the mesocarp. In addition, five new species clearly allied to A.filicaulis and A. triternata are described herein, viz. A. bracteosa, A. elsiae, A. laticostata, A. radiata, and A. refracta. The group is distinguished from other species in the genus by less sturdy synflorescences, ternate leaves with linear ultimate leaflets (except A. refracta), distinctly branched resin ducts in the petals (except A. filicaulis, A. laticostata and A. radiata), and mericarps with marginal wings and dorsal ribs (except A. elsiae). A comprehensive key to the seven species is provided together with an updated taxonomy with detailed morphological descriptions, a lectotypification, diagnostic illustrations, and maps of known geographical distributions.