A chemotaxonomic study was carried out on the Lethariella cladonioides complex, including L. sernanderi and L. cashmeriana of the subgenus Chlorea, based on extensive field surveys and a detailed morphological and chemical analysis. Only one species, L. cladonioides made up of five chemical races, is recognized. Lethariella sernanderi and L. cashmeriana are reduced to synonyms under L. cladonioides. The presence of a remarkable chemical polymorphism within the population of L. cladonioides is demonstrated. New data on the chemistry and the distribution of the species are presented.
