Phylogenetics of Sabiaceae with Emphasis on Meliosma Based on Nuclear and Chloroplast Data

摘要

Sabiaceae include over 120 species of mostly trees and shrubs found in moist forests of the Neotropics and Southeast Asia. The family includes three genera, Meliosma, Ophiocaryon, and Sabia, the first being the most species-rich and the only one found at the present time throughout the entire disjunct distribution range displayed by the family. Sabiaceae resolves among early-diverging eudicots in family-level phylogenetic studies, however, to date, no such studies have focused on the family or any of its members. Nuclear and chloroplast molecular data were used to infer phylogenetic relationships within Sabiaceae and among species of Meliosma. Sabia occupies an early diverging position in Sabiaceae and Ophiocaryon is nested within Meliosma, although monophyly of the latter cannot be rejected. Results show that Meliosma alba, found in China and Mexico, is monophyletic. The infrageneric classification of Meliosma, largely based on endocarp morphological characters, is evaluated in light of these results. Findings suggest that the intricate floral morphology of Meliosma is derived within Sabiaceae and that the basic floral plan in the family is pentamerous. Results could support the transfer of Meliosma alba to a new genus if confirmed by future research.