A review of the systematics and phylogeny of the African Proteaceae

Abstract

In Africa the Proteaceae are represented by 16 genera of which two (Dilobeia Thouars. and Malagasia L.Johnson and B.Briggs) are endemic to Madagascar and one (Faurea Harv.) is common to both Madagascar and Africa where it is widespread in forest and savannah woodland from the southern Cape to Eritrea. The remaining 13 genera are Cape-centred (10 are endemic to the western Cape) and with the exception of the monotypic riverine Brabejum L. (Grevilleoideae), are confined to fynbos (heathland) communities on oligotrophic soils. These 12 Cape heathland genera currently assigned to two subtribes (Proteinae and Aulacinae) within the subfamily Proteoideae have all been recently revised or are in the final stages of revision. Preliminary cladistic studies now suggest that they could be arranged in several new subtribes within the subfamily Proteoideae to reflect more accurately their phylogenetic relationships. Using morphological characters in a cladistic analysis, the South African Proteoideae (tribe Proteeae) resolve into two broad groups; Aulax Berg., Faurea Harv. and Protea L. form a weakly supported group while the second, large, well-supported group resolves into two clades in which the heterogeneous Leucadendron R.Br. stands apart while the other clade underpinned by Vexatorella Rourke resolves into two further groups, the ‘Leucospermum group’ and the ‘Serruria group’. The dioecious genera Leucadendron and Aulax previously united in the subtribe Aulacinae have been shown to differ markedly and should probably be placed in separate subtribes. Selection pressure, especially from fire and pollinators, has resulted in major morphological modifications in the 12 fynbos genera from the western Cape.