BioProject

Background. Of the ca. 1800 species of Aizoaceae (Caryophyllales), the vast majority belongs to subfamily Ruschioideae, a radiation restricted to southern Africa. More...

Background. Of the ca. 1800 species of Aizoaceae (Caryophyllales), the vast majority belongs to subfamily Ruschioideae, a radiation restricted to southern Africa. Tribe Ruschieae, with ca. 1600 species, comprises mainly succulent perennials that form a major component of the flora of the Greater Cape Floristic region. Drosanthemum, with ca. 110 species, has been recognized as sister to all other Ruschieae. The genus displays a vast array of different flower and fruit morphologies and the present work elucidates the question whether its division in subgenera, based on morphological characters, is reflected by molecular phylogeny.Methods. We performed molecular analyses of chloroplast and nrDNA data of 142 accessions representing 67 species of Drosanthemum. We analyzed these data using maximum likelihood (ML) tree inference and non-parametric bootstrapping (BS) analysis. Competing support patterns were investigated using BS consensus networks. For all molecularly studied accessions and 499 further, safely identified records of these species, we obtained distributional data from the database of the late Dr. H.E.K. Hartmann.Results. Drosanthemum falls in a total of nine supported clades, which correspond mostly with the previously described subgenera. Of these, two small clades remain unresolved with two superclades composed of three and four clades, respectively. Each of these clades shows a unique distribution pattern.Discussion. The nine clades vary strongly in number of members and size of distribution area, suggesting uneven rates of diversification. Most clades have representatives in the area between 33-34° S and 19-20° E. Four clades expand to the East as far as Port Elizabeth, but only two clades leave the coastal areas. Several clades espand along the West Coast, one as far as Lüderitz in Namibia. Subclades of the larger clades tend to show some geographical differentiation. Less...