New tribal delimitations in african Apiaceae

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

University of Cape Town, South Africa

Congreso; XXXV Annual Conference of the South African Association of Botanists; 2009

South African Association of Botanists

The Apiaceae is a large and taxonomically complex family comprising ca. 463 genera and 3 500 species, with a near cosmopolitan distribution. The Eurocentric classification system of Drude (1898) made little provision for the African taxa. Currently, the family is undergoing a renewed global research effort to produce a natural classification system for the family as a whole. Until recently, the comparatively small sub-Saharan African and Madagascan contingent (80 genera and 354 species) has remained largely unstudied. The high incidence of woodiness and other unusual characters, as well as the many isolated and anomalous taxa indicate that the African genera are critical to an understanding of higher order relationships within the family, particularly in the subfamilies Apioideae and Saniculoideae. As natural relationships are hard to predict on the basis of morphological characters alone, anatomical, morphological and molecular sequence data (trnQ, rps16, trnK) of a selection of species and genera were carefully studied and analyzed. In order to accommodate the unique members of the family substantial rearrangements at both the tribal and subfamilial level are proposed. Many of the African taxa occupy an early diverging position and are here referred to as “Protoapioids”. This group can readily be distinguished from the “Euapioids” (previously referred to as “remaining Apioids”) by the presence of scattered druse crystals in the mesocarp. It is proposed that the latter two groups comprise an expanded Apioideae, which can easily be distinguished from the other two subfamilies, the Azorelloideae and Mackinlayoideae, by the absence of rhomboidal crystals, the non-woody endocarp, the lignification of the mesocarp, and the presence of true wings. A new tribal classification system is proposed, in which five new tribes are described. The classification system also makes provision for previously unplaced African endemics.