alternate generation

noun

alternation of sexual with asexual generation, in which the products of one process differ from those of the other, a form of reproduction common both to animal and vegetable organisms. In the simplest form, the organism arising from sexual generation produces offspring unlike itself, agamogenetically. These, however, in time acquire reproductive organs, and from their impregnated germs the original parent form is reproduced. In more complicated cases, the first series of organisms produced agamogenetically may give rise to others by a like process, and these in turn to still other generations. Ultimately, however, a generation is formed which develops sexual organs, and the original form is reproduced