The exine is composed of tectum, columellae, foot layer and endexine.

花粉由顶盖、柱状、底及所组成。

The exine of pollen wall is of different electron density, the nexine dense and the sexine, comprising tectum, bacules, and foot layer, relatively thin.

花粉的分为和，包括覆盖、基粒棒和基足等三，只包含一。