XVI International Botanical Congess

Labordia is a Hawaiian endemic genus and Geniostoma is distributed throughout the islands of the Pacific and Indian oceans. Researchers have treated the two genera as a single genus and have placed them in their own family. Recent molecular evidence indicates that these genera are part of Loganiaceae sensu stricto. Labordia is a monophyletic lineage containing two clades. The species within each clade have distinct floral morphologies that indicate a pollination shift from entomophily to ornithophily. Additionally, Geniostoma species are hermaphroditic or gynodioecious (in New Zealand). Labordia species are strictly dioecious. ITS sequence data indicates that New Zealand geniostomas appear to be closely related to Labordia, which suggests that dioecy may have evoloved in a stepwise progression from a hermaphroditic ancestor. Additionally, sequence analysis of 5S-NTS was used to examine the biogeographic relationships within Labordia. This research is supported by the Lewis B. and Dorothy Cullman Foundation.