Androecium development and staminode diversity of Cocculus orbiculatus (Menispermaceae)

•Stamen initiation and early development in male and female flowers are similar.•Staminodes in female flowers develop abnormally late with the anthers degenerating to different degrees.•Staminode morphology varies from staminiform, spoon-shaped, navicular, tongue-shaped to petaloid structures.•Anther wall formation is the basic type, simultaneous cytokinesis results in tetrahedral tetrads.