英语语法分析

The exospore is smooth and the surface ornamentation is formed by the perispore.

外壁光滑。 周壁较厚，由周壁形成孢子的表面纹饰。

The perispore can be distinguished into three layers, i. e. an outer perispore layer, a middle perispore layer and an inner perispore layer.

周壁是由绒毡层残余物在外壁表面沉积形成， 可分为周壁内层、周壁中层和周壁外层三部分。