How does apogamy allow some ferns to reproduce without fertilization?

In botany, apogamy is a form of apomixis that allows certain ferns to reproduce without the need for gametes or fertilization.1

In this process, the sporophyte generation arises directly from the vegetative cells of the gametophyte (or prothallium) through nuclear and cell division. Rather than relying on the fusion of sperm and egg, the meristematic region of the gametophyte simply buds off a new sporophyte clonally.123

This reproductive strategy can occur naturally or be induced. For example, in some ferns, apogamy is triggered by environmental stressors, such as withholding water from the gametophytes, which prevents the liberation and functioning of sperm. Additionally, apogamy is common in certain sterile hybrids, where the plant produces unreduced spores that possess the same chromosome complement as the parent sporophyte. These spores germinate into gametophytes that bypass sexual fusion, ensuring the continuation of the life cycle despite the absence of traditional fertilization.123