In the epiphytic lichen Hypogymnia physodes in the virginal (v2) and potentially generative (g3v) phases of ontogenetic development, mycotoxins and usnic acid were determined by the enzyme immunoassay. It is shown that both age groups contain a 12-component complex of mycotoxins previously established for this lichen during extensive mycotoxicological monitoring. Differences in the levels of accumulation of the most toxic metabolites of micromycetes and usnic acid for individuals in the early and chronologically more mature state were not revealed, but a statistically significant decrease in the contents of sterigmatocystin, mycophenolic acid, citrinin and alternariol has been shown. The features of the mycotoxin profile in a given habitat and the degree of variability in the quantitative content of these substances within a single biotope are discussed. Enzyme immunoassay, Epiphytic lichens, Hypogymnia physodes, Mycotoxins, Ontogeny, Usnic acid