XVI International Botanical Congess

Hawaiian Viola comprises nine morphologically diverse taxa, six of which are single-island endemics. Analyses of internal transcribed spacer (ITS) nrDNA sequences suggest an origin of treelets and dry-habitat preference soon after the arrival of an arctic-tundra bog founder (V. langsdorffii) on Kauai. Shrubby and subshrub/herbaceous forms were produced independently two to three times on Kauai and younger islands to the east. Growth-form, foliar morphology, leaf anatomy and inflorescence architecture are phylogenetically decoupled and evolutionarily labile, resulting in the rise of four ecomorphic syndromes characteristic of Hawaiian dry forests, mesic streambanks, swamps, and open bogs.