Where do fern gametophytes usually grow?

Fern gametophytes, also known as prothallia, typically develop in microenvironments that provide deep to moderate shade, a humid atmosphere, and little competition from other plants.12

In nature, they are most commonly found growing on:
* Shaded soil banks in forests and along streams2
* Rotting logs2
* Moist rocks, often within protected crevices where light is minimal and moisture is maximal12
* Tree bark1

These structures are anchored to these surfaces by unicellular, rootlike rhizoids. While most fern gametophytes contain chlorophyll and require these specific conditions to germinate and develop, a few species have subterranean, non-photosynthetic gametophytes that lack chlorophyll and associate with fungi. Because of their specific environmental requirements, gametophytes are rarely observed in the wild and are often best known as laboratory specimens.132