Ontogenetic structure and types of cenopopulation of Hedysarum grandiflorum Pall. in the Middle Volga basin

. The need to study the current state of cenotic populations of rare plant species in nature is not in doubt for the conservation of floristic and phytocenotic diversity at the regional and world levels. The purpose of our study is to study the current state of the cenotic populations of Rare in the Middle Volga basin Hedysarum grandiflorum Pall. To characterize the ontogenetic structure of the cenopopulations, generally accepted demographic indicators were used: the recovery index (the ratio of growth to the generative fraction is calculated), the replacement index (the ratio of growth and the sum of generative and post-regenerative fractions), and the aging index (post-generative to the adult part of the cenotic populations). The population estimation was carried out by the criterion “delta-omega”.A relatively narrow range of ecological and phytocoenotic growth conditions is characteristic of the species, for the most part a patient type of life strategy. Among the limiting factors for the development of populations of environmental factors are their location at the border of the area, uncontrolled grazing in areas, excessive recreation of territories and steppe fires (natural origin and pala) in phytocenoses with the participation of a penny, career development of limestone and Cretaceous slopes, and construction debris, the appearance of dirt roads and the construction of various objects in the points of growth of the model species.The main ways of ontogenesis of the species are identified – normal, accelerated and delayed, breaks in the development of individuals, their rejuvenation and the manifestation of quasisenity were noted. The majority of H. grandiflorum develop at a normal and accelerated rate. The main indicator for determining the current state of populations and their loci is the ontogenetic structure. As an example, information on the ontogenetic composition of some cenopopulations of H. grandiflorum at the Chubovskaya Krasnaya Gorka (High Samara Zavolzhye, Russia) is given. Populations are characterized by the predominance of generative individuals. Of the registered cenopopulations, 11 is characterized as mature, 9 – transitional, 2 – ripening, 1 – young. Aggregation is characteristic of the spatial structure of H. grandiflorum.