Cultured lichens were used for chemical analysis. A few lichen substances were identified in the number of samples indicated in the parenthesis as follows: parietin (4), usnic acid with isousnic acid in some samples (9), and barbatic acid, squamatic acid, baeomycesic acid (1). The majority (61) of the samples contained unidentified substances and some samples (20) showed no significant peaks in HPLC. Parietin and its related substances are more easily synthesized in Xanthoria mycobionts similar to natural lichens. Usnic acid is more easily synthesized in cultured lichens than depsides and depsidones; however, it is often found in only cultured mycobionts. In most cultured lichens (mycobionts), unidentified substances were detected, which are probably different from the known depsides or depsidones. Depsides were detected in a few cultured cell aggregates of lichens (mycobionts). New thalli reformed by a mycobiont with photobiont in culture can produce the same depsides and depsidones as the natural lichens. The production of lichen substances in mycobionts can be changed during long-term culture. The production of lichen substances in mycobionts can be influenced by (a) the synthesized morphological structure of cultured cell aggregates of lichens, (b) the content of culture media*(agar concentration, glucose concentration, etc.), and probably (c) physical environmental conditions