XVI International Botanical Congess

In Hawaii, rapid fixation of new groundplans may be favored by founder effect and inbreeding. In Tetraplasandra, stamen and carpel number and gynoecium position vary widely. The occurrence of hypogyny in T. gymnocarpa is unique among Araliaceae. ITS and 5S-NTS data place this taxon in a derived position within the genus. Trends in organ reduction are evaluated in the context of comparative ovary ontogeny. In Clermontia (Campanulaceae), 15/22 species have a second whorl of petals in place of sepaloid first-whorl organs. 5S-NTS data show that this feature is derived, and gene expression studies implicate alterations in the floral homeotic B function. These systems are compared and contrasted.