Appalachian shoestring fern

The Appalachian shoestring fern, scientifically known as Vittaria appalachiana, is a type of filmy fern belonging to the family Pteridaceae. These ferns are typically epiphytes, meaning they grow on other plants, and are found in tropical regions, though some species extend into temperate zones.1

A unique characteristic of the Appalachian shoestring fern is that it appears to exist only as independent gametophytes, which are the sexual reproductive stages of ferns. These gametophytes inhabit cool, shaded areas under cliffs and boulders. Unlike most ferns, this species seems unable to complete its sexual life cycle to produce sporophytes (the dominant, leafy stage of a fern) in the wild. Instead, it reproduces asexually through small vegetative offsets called gemmae, which are spread by air currents. Its closest relatives are found in Asia and tropical regions. Another fern, Vittaria lineata, also called a grass fern, shares similar characteristics.12