The term proteroginia, in biology, indicates the case of hermaphroditism where, although both gametes are present, the female ones first develop and then the male ones. Pro-preroginia is the opposite condition of the proterandrìa.
The term proteroginia comes from the Greek and is composed of the words próteros (front) and ghynḗ (woman, female).
In the field of zoology, proteroginia is the condition of hermaphrodite individuals in which the female gametes mature before the male gametes.
The prothyrania is however rarer in the animal kingdom; nevertheless this type of hermaphroditism is widespread in many species of fish (such as labridae and pomacanthidae) where the specimens are born and live the first part of life as females and then become later, with the passing of the age of the males in all respects.
In botany, proteroginia is typical of insufficient hermaphrodite plants: this situation occurs when in the hermaphrodite flowers the female organs (gynaeceum, pistil) reach sexual maturity before the androceus (stamens), thus making self-fertilization impossible.
This characteristic is typical of many grasses and plantaginaceae, and in the species of the genera Aristolochia and magnolia.