The early development of Hypogymnia physodes from soredia to the formation of stratified lobes has been studied experimentally in the vicinity of a copper-smelting plant in theMiddle Urals. SEM investigations combined with life table analyses of early developmental stages revealed decreases in soredial survival and developmental rate in polluted localities. Non-stricatified pre-thallus stages without an epicortex were tolerant to toxic impact and were able to survive even in the zone with the highest pollution (lichen desert zone). The sensitivity of developmental stagesancreased after stratified lobes had developed.