Summary
The African genus Welwitschiella has traditionally been placed in tribe Heliantheae. Our phylogenetic analysis of chloroplast DNA ndhF sequence data, however, reveals that it is part of tribe Astereae. In order to assess the relationships of this genus within the tribe, we produced a phylogeny based on ITS (nrDNA) sequence data of a sample including Amellus, African Conyza, Chrysocoma, Felicia spp., Mairia, Poeciliopsis, Printzia, Welwitschiella and Zyrphelis. Both parsimony and Bayesian analyses were done. The Bayesian analysis showed that African genera form a basal grade in tribe Astereae along with the Chinese Nannoglottis and South American and New Zealand genera, with Printzia being the earliest diverging member of the tribe. Mairia occupies an isolated position. Amellus, Chrysocoma, Felicia, Poecilolepis and Zyrphelis belong to subtribe Homochrominae, a South African radiation that also includes the St Helena endemics Commidendron and Melanodendron. Pteronia appears isolated, though it might be close to the Homochrominae. Welwitschiella is placed in the latest diverging African clade, subtribe Grangeinae, which also includes Grangea, Psiadia, Nidorella, and the African Conyza species except C. gouani. This subtribe is sister to the Eurasiatic subtribe Bellidinae, and together they are sister to the Astereae crown lineages of Australasia-Asia and South and North America.