Fourteen species of Crambe sect. Dendrocrambe (Brassicaceae) are endemic to the Macaronesian islands and are found in a variety of habitats. A previous study using ITS sequence data indicated that the island endemics form a monophyletic group comprised of three major lineages. Although interspecific relationships were resolved in some cases, relationships among the three major groups and among other species were not sufficiently resolved. We are performing a cpDNA restriction site study to provide additional resolution and to have an independent molecular marker to test previous hypotheses of the evolution of Crambe in Macaronesia. Our preliminary cpDNA results are congruent with the previous ITS study and suggest that inter-island colonization and subsequent differentiation is the major pattern of evolution in this group.

Key words: biogeography, Brassicaceae, Crambe, islands, Macaronesia