oosphere

We thus have a process of “multiple fertilization”; the oosphere really represents a large number of undifferentiated gametes and has been termed a coenogamete.

Guided by the synergidae one male-cell passes into the oosphere with which it fuses, the two nuclei uniting, while the other fuses with the definitive nucleus, or, as it is also called, the endosperm nucleus.

The subsequent behavior of the pollen cell, its division and its fertilization of the germinal vesicle or oosphere, leave no doubt as to its analogy with the microspore of vascular cryptogams.

In Cystopus Bliti the oosphere contains numerous nuclei, and all the male nuclei from the antheridium pass into it, the male and female nuclei then fusing in pairs.

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.