Inflorescence and floral development of Dipteronia sinensis (Sapindaceae): Demonstration of developmental constraints in the shaping of the flower

•Details of floral morphology and development of dipteronia are presented for the first time.•The study clarifies the distinction between staminate and pistillate flowers developing on the same monochasial cyme.•Petal development is sequential and inversely correlated with loss of stamens.•Symmetry and stamen and carpel insertion is regulated by subtle shifts in timing of initiation and growth of floral organs.•Floral development in Sapindaceae indicates that monosymmetry is probably ancestral in the family.