The Canary Islands, located off the northwest coast of Africa, are home to approximately 16 species of temperate herbaceous legumes in the genus Lotus (Loteae: Fabaceae). Members of this group include species marked by a distinctive forked style, a feature seen only in Lotus subgenus Pedrosia. Although primarily restricted to African offshore islands, members of subgenus Pedrosia are also found on the African mainland. To investigate the geographic origin and morphological evolution of the Canary Island species group, we generated a phylogeny based on internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA. In particular, we ask the following questions: (1) Are the Canary Island species the result of a single introduction or multiple introductions?; (2) What are the closest relatives to the Canary Island species?; (3) What is the most likely landmass of origin for the Canary Island species?; and (4) Did the distinctive forked style of subgenus Pedrosia arise once or multiple times? Results to date suggest that Lotus subgenus Pedrosia is monophyletic, but that the Canary Island species are not. Rather, two insular species groups are identified, both of which appear independently related to species of Lotus found on the African mainland. The implications of these findings are that the Canary Island species are the product of two independent introductions, each from Africa. In light of morphological evolution, these results also suggest that the distinctive forked style marking Lotus subgenus Pedrosia arose once, rather than multiple times. We are currently investigating whether alternative plastid genes (trnL and matK) support these findings, and what the overall implications are for understanding biogeographic and morphological patterns in the Canary Island flora.

Key words: Canary Islands, ITS, Lotus subgenus Pedrosia, molecular phylogeny