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

花外壁由顶盖、柱状、底及外壁所组成。

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

花壁的外壁分为外，外包括覆盖、基粒棒基足等三，只包含一。