XVI International Botanical Congess

Although molecular and morphological data each has its own problems, both provide powerful evidence about the derivation of island plants. Such evidence not only reveals relationships within groups on islands (adaptive radiation or in situ derivation) but also reveals relationships between island plants and their continental relatives (ex situ derivation). Morphological data is complementary to molecular data and is important in providing a direct link between phylogenetic pattern and evolutionary scenarios of dispersal and radiation. In this paper comparative molecular and morphological data are discussed for island plants from St. Helena (Commidendrum, Asteraceae) and the Tristan da Cunha archipelago (Phylica, Rhamnaceae), as well as from the South Pacific (Fuchsia, Onagraceae and Cyrtandra, Gesneriaceae). Scenarios for the origin of these groups are presented.