ABSTRACT
Reproduction is a fundamental problem of theoretical botany and at the same time is of primary practical importance. Angiosperms are reproduced in most cases by seeds. The embryo and endosperm of a seed can be formed in two ways: by amphimixis or by apomixis. This chapter aims to develop a comprehensive characteristic of adventive embryony as one of the modes of seed reproduction in angiosperms and to reveal main cytoembryological regularities. It highlights major problems of embryological development of the species with nucellar and integumentary embryony on the basis of original data and a survey of literature with respect to representatives of more than 250 species from 57 families of angiosperms. Some new principles are proposed with respect to the development of male and female generative structures, development of sexual and adventive embryos, and peculiarities of endospermogenesis.
