The giant lobelias: pachycauly, biogeography, ornithophily and continental drift

Recent revisions of the Asian, Jamaican and African species of pachycaul lobelias raise a number of evolutionary and biogeographical problems. Discussion of the apparent forest pachycaul ancestry of the African species is applied to problems of biogeography, pollination and Continental Drift. The available facts are accommodated in an hypothesis, wherein the African species are considered to have had an American ancestry. Herbaceous habit, dry fruit, wingless seeds, enhanced alpine pachycauly and entomophily are considered advanced characters. Further investigations, particularly with regard to the American species, are suggested to test the hypothesis.