Anthers sessile, circular, 2-loculed, introrse, connate into a synandrium, dehiscence longitudinal.

花无梗，圆，2室，内向，合生的成为聚，开裂纵向。

Calyx lobes 4 or 5 or rarely more, usually short, caducous or persistent, apex usually obtuse, rarely connate and then calyptrate.

裂片4或5或很少更多，短，早落或宿存，先钝的，很少合生然后具帽状的。