Fragilin
Fragilin is a chemical compound of the anthraquinone class. It has the molecular formula and is a chlorinated derivative of parietin. In 1965, it was reported as a constituent of the lichens Sphaerophorus fragilis and Sphaerophorus coralloides. It has since been found in a variety of other lichens including Nephroma laevigatum, Caloplaca, Xanthoria parietina, and others.