oospore

C. Formation of zoospores by oospores. z, Free zoospores.

The oospores give rise to neuter plants, the tetraspores to ♂ or ♀ plants.

The oospores of the Saprolegniæ, when arrived at maturity, possess a tolerably thick double integument, consisting of an epispore and an endospore.

After impregnation the fertilized oosphere immediately surrounds itself with a cell-wall and becomes the oospore which by a process of growth forms the embryo of the new plant.

After the production of this oospore the parent filament gradually loses its vitality and slowly decays.