Heterantherous flowers of Senna bicapsularis (top left), S. surattensis (top right), Melastoma dodecandrum (bottom left), and Fordiophyton faberi (bottom right), showing differentiations in androecia. Photographed by Zhong-Lai LUO (top, bottom left) and Lei GU (bottom right). See LUO et al., pp. 43–56 in this issue.