Figure 2.

Estimates of divergence minima for putative relict lineages in relation to the estimated timing of establishment of the Benguela upwelling system. Values illustrated are the mean of two independent runs of the Markov chain. Thin lines, lower credibility intervals; asterisks, first appearances in southern African fossil record; horizontal arrows, variation in published minimum estimates for the timing of onset of radiation in Cape clades with medium to high species diversity, resulting from differences in sampling, calibration and dating methods. The Phylica phylogeny was directly calibrated using the estimated timing of origin of volcanic islands, and therefore yields a maximum estimate of the timing of onset of radiation (Richardson et al. 2001). Other Cape radiations (Ehrharta, Indigofera, Moraea, Pelargonium and Restionaceae) were secondarily calibrated using divergence estimates obtained from other dated phylogenies, themselves calibrated with fossils, thereby yielding minimum estimates for the onset of radiation (Goldblatt et al. 2002; Schrire et al. 2003; Verboom et al. 2003; Linder & Hardy 2004; Bakker et al. 2005; Mummenhoff et al. 2005).