A detailed chemical and morphological study has been carried out on West European specimens of Cladonia subulata (L.) F. H. Wigg. and C. rei Schaer. Using thin-layer chromatography (TLC), three different chemotypes were found, which did not show any correlation with distribution, substratum, habitat or any of the morphological characteristics mentioned in recent floras. Moreover, the application of UV (long-wave) proved to be unreliable for detecting homosekikaic acid and thus for distinguishing the two species. It appears that only one species, with three chemotypes, exists in Western Europe. Cladonia subulata is therefore another of the more than ten Cladonia species reported so far that can contain either homosekikaic and/or fumarprotocetraric acid.

Induction of secondary compounds in three reindeer lichens (Cladonia arbuscula, C. rangiferina and C. stellaris) was studied under controlled conditions in a growth chamber. Acetone rinsed (secondary compounds removed) lichen mats were subjected to three light regimes (PAR, PAR+UV-A and PAR+UV-A+UV-B), each combined with simulated herbivory (clipping). After 4 weeks, lichen extracts were analyzed by HPLC for any synthesized secondary compounds. UV-B induced the synthesis of usnic acid in C. arbuscula and C. stellaris and melanic pigments in C. rangiferina. Atranorin, fumarprotocetraric acid and perlatolic acid were not influenced by light quality. None of the identified compounds were significantly influenced by clipping. In conclusion, all three lichen species responded to UV-B radiation by developing cortical UV-B absorbing pigments that might function as protective screens. However, the experiment did not produce evidence for a herbivore-deterrent role of compounds studied.