Molecular phylogenetic relationships of Olacaceae and related Santalales

As traditionally circumscribed, the family Olacaceae contains a morphologically diverse assemblage of genera that has historically caused much confusion regarding their classification. For example, Olacaceae contain parasites and nonparasites, climbing lianas and trees, and members with dichlamydous and monochlamydous perianths. This family is basalmost in the sandalwood order (Santalales), thus it represents the staging ground for many innovations that evolved in subsequent groups. The present molecular phylogenetic study has obtained DNA sequence data (nuclear SSU rDNA and chloroplast rbcL and matK) for all but two of the 28 genera in this group. Maximum parsimony and Bayesian analyses have resolved seven clades, well-supported by molecular and morphological characters. Root hemiparasitism appears to have first evolved in the clade containing Ximenia whereas clades between that one and the outgroup appear to be entirely autotrophic.