The genus was
circumscribed in 1968 by the German lichenologist
Gerhard Follman, with
Roccellinastrum spongoideum assigned as the
type species. This
byssoid lichen (appearing wispy, like teased wool) was found growing on cactus spines in the
fog oases of western Chile. Follman classified the genus in the family
Chrysothricaceae, as he emphasized the
taxonomic importance of the byssoid
thallus, and the similarity of the
apothecium and
ascus structure to those in that family. In 1983,
Aino Henssen and colleagues
emended the genus and placed it in the family
Lecideaceae. ==Description==