Tetraplasandra is part of a generic complex that includes Munroidedron, Reynoldsia, and Gastonia. Phylogenetic relationships and generic delimitations of the Tetraplasandra group have been historically problematic. Our previous molecular analyses based on independent and combined ITS and 5S-NTS data sets revealed that the Hawaiian taxa of the Tetraplasandra group (Tetraplasandra, Munroidendron, and Reynoldsia sandwicensis) are monophyletic and Reynoldsia is paraphyletic. In Tetraplasandra, superior ovaries are derived from inferior ovaries. The shift to superior ovaries in Tetraplasandra is associated with a reduction in floral parts and may be related to a change in pollination syndrome. A cladistic analysis of the Tetraplasandra group was generated based on floral and fruit morphology and was combined with the ITS and 5S-NTS data. Our results suggest that plesiomorphic floral characters of the family, along with superior ovaries, are derived characters within the Tetraplasandra group.

Key words: Araliaceae, Hawaiian islands, molecular, morphology, superior ovaries, systematics