Why is it necessary to observe the anatomical structure of flowers and fruits in plant classification?

Anatomical observation of flowers and fruits is necessary in plant classification because the morphology and structure are relatively stable. When biologists classify angiosperms, flowers, fruits and seeds are often used as the important basis for classification, because reproductive organs such as flowers, fruits and seeds appear later than vegetative organs such as roots, stems and leaves in a plant's life, and their survival time is short, which is less affected by the environment and their morphological structure is relatively stable.