A PHYLOGENETIC ANALYSIS OF HYDRANGEACEAE BASED ON MORPHOLOGICAL DATA

Phylogenetic analyses show Hydrangeaceae to be a monophyletic group in the Cornales, and this article uses parsimony analysis of morphologic al data to identify evolutionary relationships in the family. All of t he most parsimonious cladograms show that (1) Jamesia, Fendlera, Fendl erella, and Whipplea a form a monophyletic group that is the sister gr oup of the rest of the family; (2) Philadelphus is monophyletic and is the sister group of Carpenteria; (3) Deutzia is monophyletic; (4) Can diandra and Deinanthe form a monophyletic group; (5) all species of Hy drangea, as well as Broussaisia, Dichroa, Decumaria, Pileostegia, and Schizophragma, form a monophyletic group (the ''hydrangea'' clade); (6 ) three monophyletic groups-the ''anomala'' clade, the ''heteromalla'' clade, and the ''macrophylla'' clade-make up the ''hydrangea'' clade; and (7) Platycrater is the sister group of the ''hydrangea'' clade. T he results indicate that Hutchinson's tribe Carpenterieae is paraphyle tic and includes some of the most basal clades in the family. Earlier hypotheses that Deutzia was derived from Philadelphus are not consiste nt with the results. The paraphyly of Hydrangea is consistent with the results of an earlier phylogenetic analysis based on sequences of the chloroplast gene rbcL. In the ''hydrangea'' clade, Broussaisia and Di chroa, two tropical genera with fleshy fruits, are sister Laxa in a cl ade that includes Hydrangea hirta, H. scandens, and H, macrophylla. Hy drangea heteromalla and H. paniculata are most closely related to;he c limbing ''genera'' Schizophragma, Pileostregia, and Decumaria. Most sp ecies of Hydrangea form part of the ''anomala'' clade, which includes species circumscribed as section Cornidia as well as H, involicrata, H . aspera, N. quercifolia, H, sikokiana, H. arborescens, and H. anomala . These results, together with those from a phylogenetic analysis of t ile family based on rbcL gene sequences, indicate that classifications of Hydrangeaceae require extensive revision to provide greater utilit y and reasonable insights on evolutionary relationships.