A TAXONOMIC REVISION OF THE HAWAIIAN SPECIES OF THE GENUS CHAMAESYCE (EUPHORBIACEAE)

A revision of the species in the genus Chamaesyce native to the Hawaiian Islands is presented, based on morphological as well as numerical and biosystematic data. A discussion of the acceptance of Chamaesyce at the generic level is given and contrasted to the more traditional opinion of placing the group as a subgenus within the genus Euphorbia. The history of the Hawaiian native species is explained along with a comparative discussion of the taxonomic characters. Hybridization experiments were conducted and the results analyzed. Numerical studies were completed using graph clustering analysis to evaluate the previous classification of Sherff (1938) and a cladistic approach utilized to estimate a possible evolutionary history. A discussion, with reference to the genus Chamaesyce, of the biogeography and floral ancestory of the Hawaiian Islands is presented. The systematic treatment accepts 29 taxa of 14 species and 15 varieties of seven of these species.