Vittaria appalachiana

Vittaria appalachiana, or the Appalachian shoestring fern, is a fern species in the subfamily Vittarioideae of the family Pteridaceae. It is native to moist and shaded outcrops in the Appalachian Mountains. It is notable for existing only in the gametophyte stage of development, unlike other fern species in which the sporophyte stage predominates. The species reproduces asexually through gemmae. The species was known to bryologists, who at first confused it with a liverwort. Aaron John Sharp brought the species to the attention of pteridologists Warren H. Wagner and Alma Gracey Stokey. It was formally named by Donald R. Farrar & John T. Mickel in 1991....read more on Wikipedia.