XVI International Botanical Congess

Section Hoarea (Sweet) DC. is the largest section of the genus Pelargonium L=Hérit. comprising more than 80 species. All members are deciduous geophytes with turnip-shaped tubers covered with flaking periderms and all species have a short flattened stem from which the leaves and scape emerge. The section is almost confined to the winter rainfall area along the west and south coasts of southern Africa. Attempts to subdivide the section remain unsatisfactory. Floral structure combined with pollen morphology support the subdivision of only four smaller groups with Hoarea, consisting of 22 species only. The delimitation of these four groups is fairly well supported by other characters like chromosome number and protein analysis. The sequencing of the ITS region seems to give interesting results and could probably be the key to a proper subdivision of the section as a whole. Preliminary results on the trnL-F sequence for 68 representatives of Pelargonium support monophyly for section Hoarea (Bakker et al. in press), although their study included only four species of the section.