The phylogenetic positions of southern African Apiaceae relative to subfamilies Apioideae and Saniculoideae

CALVIÑO, C. I., DOWNIE, S. R., TILNEY, P. M., AND VAN WYK, B.E.

Austin, Texas, USA

Congreso; Botany 2005; 2005

American Society of Plant Taxonomists (ASPT) and Botanical Society of America (BSA)

The family Apiaceae comprises some 455 genera, with 38 of these occurring in southern Africa. Many of these African genera have been postulated to be important in the early evolution of core Apiaceae (i.e., Apioideae, Saniculoideae, and the Azorella clade) or to be links between subfamilies Apioideae and Saniculoideae. In this study, we expand results of a previous phylogenetic analysis of chloroplast rps16 intron sequences by incorporating additional representation of southern African members of Apiaceae. Genera not restricted to southern Africa were included in order to represent major lineages within Apioideae and Saniculoideae. In addition, several members of Azorelloideae and Mackinlayoideae were used as outgroups and Aralia chinensis was used to root the trees. The resulting matrix was analyzed using maximum parsimony and Bayesian analyses. Historical biogeography of the earliest splits within Apioideae was analyzed using the program DIVA ver 1.1. The relative phylogenetic positions of southern African umbels relative to subfamilies Saniculoideae and Apioideae are discussed. Among basal Apioideae, two additional major lineages are inferred (the Annesorhiza clade and Lichtensteinia); these clades are allied closely with tribe Heteromorpheae. Heteromorpheae is expanded to include Pseudocarum. This results are also supported by preliminary analyses of nrITS data. The clade of Steganotaenia plus Polemanniopsis is maintained as sister to Saniculoideae. Core Apiaceae is also expanded to include a fourth major clade (Hermas, treated previously as a hydrocotyloid genus). The phylogenies estimated herein reveal that 80% of the basal genera studied to date within Apioideae are endemic to southern Africa, and within Saniculoideae all southern African genera occupy a basal position. Despite the small number of genera occurring in southern Africa, this region is of great importance in the early evolution of both subfamilies.