Abstract
The generic boundaries and relationships of Annesorhiza Cham. & Schlechtd., Chamarea Eckl. & Zeyh. and two deciduous species Peucedanum L. (P. filicaule and P. triternatum) have until now been unsatisfactory. This is mainly due to the fact that the species are inconspicuous, poorly known and poorly represented in herbarium collections. The present study has resulted in the recognition of three sections and 21 species within a broadened concept of Annesorhiza. The genus Chamarea is included in Annesorhiza as a section and P. filicaule and P. triternatum are transferred to Annesorhiza to make the genus Peucedanum more uniform. A new section, Ternata Vessio et al., and a new species, A. elsiae Vessio et al., are described.
Morphological, anatomical, phenological and geographical evidence is used to investigate the relationships between the genera and species. These characters are discussed and illustrated. The anatomy and structure of leaves (pinnate or ternate), as well as the symmetry, morphology and anatomy of the fruit, and the size and shape of sepals proved to be of taxonomic value in distinguishing between taxa. The data is analysed cladistically, using Glia Sond. as an outgroup. The analyses show that all members of the study group form a monophyletic group characterized by deciduous leaves and the periodic replacement of fleshy roots. Within this larger group (Annesorhiza sensu lato) three monophyletic entities can be distinguished, each of which is treated as a formal sections: Section 1. Annesorhiza sensu stricto (including all except three species of the genus Annesorhiza sensu stricto); Section 2. Chamarea (including all except two species of the genus Chamarea); Section 3. Ternata Vessio et al. (a new section to accommodate all species with ternate leaves – three from Annesorhiza sensu stricto, two from Chamarea and two from Peucedanum).
A formal taxonomic treatment is presented, including keys to the recognized sections and species, correct nomenclature, typification, descriptions and distribution maps.
Dr. P.M. Tilney