Which types of rock support different fern species?

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tree fern — fern Tree fern (*Cyathea medullaris*).

Different fern species are associated with specific types of rock, as their growth is often dictated by the chemical composition of their substrate. These plants are categorized based on their preference for either acidic or alkaline environments:

Acidic rocks: Species associated with granite, sandstone, and quartzite are distinct from those found on other rock types.1
Alkaline rocks: Species that thrive on calcite and dolomite form a separate group of ferns.1
Specialized rocks: A limited number of fern species are confined to serpentine and related rock formations.1

Ferns that grow on rocks, known as epipetric ferns, typically inhabit fissures and crevices in cliff faces, boulders, and taluses where they can find protection and moisture. Even for species that are adapted to sun and drought, the gametophyte stage generally requires the protected, humid microenvironment found within these rocky crevices.1