Alveolae of the proximal exine are smaller and less regular in form than those at equatorial region.
近极区的穴较之赤道区的要小且形状较不规则。
2
Except for some differences in exine ornamentation and pollen size, there is no great evolutionary divergence among genera in pollen morphology.
总体来讲，花粉没有大的演化分异，只是表面纹饰和花粉大小有一定的差异。
3
Method: Pollen exine ultrastructure were compared for 18 populations growing under in the same environment by means of scanning electron microscope (SEM).