Ontogenetic structure of lichen populations as the index of the condition of the urbanized territories

The results of population monitoring in lichen indication promote the detection of resistance of lichen species to the pollution of environment. The population of Xanthoria parietina (L.) Th. Fr. on the territory of the city of Samara and in the neighborhood of the Bolshaya Glushitsa settlement (Bolsheglushitsky district, Samara region) (Russia) were studied. For identification of ontogenetic conditions of talluses, the approaches and a nomenclature of population and ontogenetic researches of Magnoliophyta were used. Taking into account the exposition, the projective cover of Ulmus pumila trunks with Xanthoria parietina talluses was revealed. On Ulmus pumila tree stems in the Bolshechernigovsky municipal district of Samara region the prevailing ontogenetic group in populations of Xanthoria parietina is young generative group, within the city it is mature generative group. Talluses in the same course of ontogenetic development have the least area, and then, the vitality, on the western part of a trunk, and the greatest on the south side. At the same time the vital level of tallus directly depends on the level of environmental pollution. The decrease in the number of talluses is related to indexes of density, illumination, natural tree mortality, cuttings, fires, diseases of tree species