Phylogenetic Relationships in Buxaceae Based on Nuclear Internal Transcribed Spacers and Plastid ndhF Sequences

Sequences of nuclear internal transcribed spacers (ITS) and plastidndhFfrom 25 representatives of Buxaceae were analyzed separately and in combination to resolve phylogenetic relationships among and within genera; parsimony and maximum likelihood methods were used. The results of the two single‐gene analyses were generally congruent, and the trees from the combined analysis were better supported. Two major clades were identified within the Buxaceae family: the clade ofPachysandra, Sarcococca,andStylocerasand the clade ofBuxusandNotobuxus. PachysandraandSarcococcawere two strongly supported monophyletic groups. The sister relationship betweenSarcococcaand the clade ofPachysandraandStyloceraswas also strongly supported. American and EurasianBuxuseach formed a strongly supported clade. The controversial genusNotobuxuswas embedded among African members ofBuxus;B. hildebrandtiiwas sister toNotobuxus,with strong support. Relationships withinBuxusandSarcococcawere only partially resolved.