Distribution regularities of tree species of the Rosaceae family in shrubs in river valleys and a streak in the flora of the Nakhchivan Autonomous Republic

The presented article provides information about the shrub vegetation of the river basins and valleys of the woody species of the Rosaceae family in the flora of the Nakhchivan. The river basins of Arpachay, Nakhchivanchay, Alinchachay, Havushchay, Gilanchay and river basins of the Sharur, Shahbuz, Julfa and Ordubad districts were studied as the research object. The conducted research allows to determine the important features characteristic of the woody species of the Rosaceae family spreading in the river valleys and riverbanks. In the structure of the steppe complex, shrub plants, especially woody species of the Rosaceae family, occupy an important place. They are part of the bush steppes, form independent groups and form unique formations. Both the sandy areas of the banks of rivers and streams, as well as the bushes found on the mountain slopes on the right and left banks of the rivers, differ sharply in terms of their species composition. In the studied vegetation class, 6 formations, 13 associations and 1 sub-association were determined by us for the first time and a phytocoenological classification of vegetation was given. In formation 1, 2 associations dominated by Rosa canina are found along the river valleys mentioned above. In the 2nd formation, 2 associations are identified, dominated by the species Crataegus meyeri . Prunus fenzliana , P. divaricata , and P. nairica species are also widely spread in this grouping. In the 3rd formation, 3 associations with a significant abundance of almond bushes and 1 sub-association identified by us for the first time. Prunus fenzliana is the dominant species in the subassociation. At the same time, Rosa canina and R. buschiana species are noticeably widespread in the grouping. The composition of the 4th formation includes 3 associations dominated by Crataegus meyeri , C. caucasica , C. monogyna , Sorbus graeca , and S. persica species. The 5th formation contains 2 associations dominated by Cotoneaster melanocarpus , C. integerrimus , Rosa canina , R. hracziana species, and the 6th formation contains 1 association dominated by Prunus microcarpa species.