The majority of xanthones reported from fungi, bacteria, and lichens, and particularly those reported relatively early on, have a monomeric and fully aromatized structure. These include arthothelin, asemone, asperxanthone, austocystins, bikaverin, chaetoxanthones, chodatin, conioxanthone A, erythrommone, emericellin, globosuxanthones C and D, griseoxanthone C, lichexanthones and norlichexanthones, Microsphaeropsis xanthones, mycoxanthone, Phoma and Phomopsis xanthones, pinselin and pinselic acid, sterigmatocystins, tajixanthone, thiomelin, thiophanic acid, thiophaninic acid, thuringione, umbilicaxanthones, vinetorin, varixanthone, vertixanthone, and Wardomyces and Xylaria xanthones.Arthothelin. Santesson reported observing this compound in the mass-spectral analysis of the lichen Leconora reuteri. 65 Arthothelin (2,4,5-trichloronorlichexanthone, 19, Figure 2) has