What is apogamy in ferns?

In ferns, apogamy is a form of apomixis—an asexual reproductive process—in which the sporophyte generation develops directly from the gametophyte without the need for gametes or fertilization.12

In this process, the prothallium (the gametophyte) produces a new sporophyte through nuclear and cell division on its vegetative cells. This can occur naturally in certain species, such as the holly fern (Cyrtomium falcatum), or it may be induced in normally sexual ferns by environmental stressors, such as withholding water or using specific culture media.13

Apogamy is also a common reproductive strategy in many sterile fern hybrids. In these cases, the fern produces unreduced spores that possess the same chromosome complement as the parent sporophyte. These spores germinate into gametophytes that bypass sexual fusion, instead budding off a new sporophyte clonally.3