Leuckert, C./ Mathey, A. 1975: Beiträge zur Chemotaxonomie einiger xanthon-haltiger Arten der Flechtengattung Buellia. - Herzogia3: 461-488. [RLL Suppl.] Abstract: Fifty-two specimens of 8 species of the genus Buellia which contain xanthones have been studied by means of lichen mass spectrometry, thin layer chromatography, paper chromatography and partly chromatogram spectral photometry. The chemical composition of B. concinna, B. geophila, B. vernicoma has been studied for the first time. In all specimens several related xanthones have been found which differ in degree of O-methylation and chlorination respectively; in most cases the xanthones with three Cl substitutes are the main compounds. - For the main compound of B. granulosa (of the 6-O-methyltrichlornorlichexanthone type) the name granulosin is proposed. The taxonomical significance of the detected xanthones has been discussed. The species B. anisomera and B. granulosa - which show transitory forms - are distinctly separated by means of different xanthones.