WOLFE, ANDREA D.1*, CHRISTOPHER P. RANDLE1, and KIM E. STEINER2. 1Department of EEOB, The Ohio State University; 2Department of Botany California Academy of Sciences. - Phylogeny and biogeography of Orobanchaceae reconstructed from nuclear rDNA 5.8s and ITS sequence data.
Orobanchaceae, as recently redefined, has 88 genera and ca. 1530
species. Most taxa are distributed in temperate regions of the world
with the highest density of genera and species in the northern
hemisphere and in Old World floristic regions. We sequenced the
nuclear rDNA 5.8s and ITS regions from 29 parasitic and six
nonparasitic genera from Lamiales to reconstruct the phylogeny of
Orobanchaceae. Our sampling included all of the major parasitic genera
and several of the smaller genera from throughout the range of
distribution. The ITS phylogeny supports the monophyly of
Orobanchaceae with Lindenbergia as the basal lineage. Genera with
distributions in southern and eastern Africa are located in the most
derived position of the tree. The topology of the ITS tree suggests an
origin of Orobanchaceae in Asia with subsequent migration of elements
to North America and the Mediterranean region via the Tethyan seaway,
followed by dispersal to northeastern Africa and a secondary
diversification of genera throughout the southern hemisphere.
Key words: biogeography, Orobanchaceae, parasitic plants, phylogeny, Scrophulariaceae