Phylogenetic reconstruction ofFicussubg.Synoeciaand its allies (Moraceae), with implications on the origin of the climbing habit

The infrageneric classification ofFicus(Moraceae) has raised concerns since Berg put forward his six subgenera system. Molecular analyses have revealed some unnatural groups within this system. The status ofF.subg.Synoeciaand the relationships between this subgenus and its allies are among the major challenges facing classification within the genus. To resolve these problems, we reconstructed the phylogenetic trees with three nuclear markers from 147 ingroup taxa (including approximately half ofF.subg.Synoeciaspecies and three-fifths ofF.subg.Ficus) and implemented ancestral area and life-form reconstructions to trace the evolutionary history. Results showed thatF.subg.SynoeciaandF.subg.Ficus(exceptF.subsect.Ficus) constituted a well-supported monophylum, which is sister toF.subg.Terega. This monophylum comprises two clades: one clade coversF.subsect.FrutescentiaeofF.sect.FicusandF.subsect.PlagiostigmaofF.sect.Pogonotrophe, and the other coversF.sect.Eriosycea,F.sect.Apiosyceaand the rest ofF.sect.Pogonotrophe.Ancestral area reconstruction revealed that the first clade has a distinct origin in East Asia, but the second one shows fewer obvious signs. Ancestral life-form reconstruction suggested that the climbing habit, a key trait used to divideF.subg.FicusandF.subg.Synoecia, has evolved independently more than four times, rendering it an unsuitable characteristic to circumscribe the subgenera. Thus, we mergedF.subg.SynoeciaandF.subg.Ficus(excludingF.subsect.Ficus) into one subgenus, containing two newly delimited sections and six new synonyms.