ZIMMER, ELIZABETH ANNE1,2*, GERARD ALLAN1,2,3, ANDREW MEDINA-MARINO1,4, and WARREN L. WAGNER2. 1Laboratories of Analytical Biology, Museum Support Center, Smithsonian Institution; 2Section of Botany, Department of Systematic Biology, NMNH, Smithsonian Institution; 3Department of Biology, Arcadia University; 4Department of Biology, Caltech. - Origin and Biogeography of Hawai`ian Melicope .
In the Hawai`ian archipelago, the genus Melicope (Rutaceae)
has undergone an extensive radiation. Although one of the largest
angiosperm genera in the islands with ~48 species, these Melicope
species have lacked any recent revisionary or phylogenetic study.
Based on morphological characters, the Hawai`ian and related Marquesan
species have been assigned to section Pelea by Hartley, but
species delimitations within that group are unclear, as many of the
taxa currently recognized as species may only be distinctive
geographical forms of widespread species. Other questions of interest
in this group are the number and nature of introductions of
Melicope into these islands and the possible inclusion of the
endemic Hawai`ian genus Platydesma as a highly derived member
of Hawai`ian Melicope . We have produced an initial molecular
phylogeny focussing on Hawai’ian and Marquesan taxon relationships
using the nuclear ribosomal ITS spacer and the chloroplast trn
L region. Four most parsimonious trees were obtained in a maximum
parsimony branch-and-bound search. All four indicated a single origin
for the Hawai`ian Melicope including Platydesma .
The Hawai`ian islands as source area for introduction to the Marquesan
archipelago, previously unconfirmed for any other taxa, also are
supported by the molecular trees.
Key words: island biogeography, nuclear and chloroplast gene spacers, plant molecular systematics