Home – Home – Jornals – Contemporary Problems of Ecology 2013 number 4

The present situation in the systematics of such a widespread genus as birch (Betula L.) involves complications. The attempts to study a large number of the species of this genus, described in Siberia and in the Russian Far East, strike on an insurmountable obstacle – impossibility to detect them for the second time, or, relying on the described characters, to find the species identical to the type samples. Very high variability of all the characters is typical for these species. In the southern regions of West Siberia, this relates to Betula pendula and B. microphylla, while in East Siberia and in the northern regions of Russian Far East this relates to Betula pendula (=B. platyphylla) and B. lanata. Intense and widespread hybridization exists between these species; in this connection, studies of this species over the whole territory of Northern Asia began. The studies were carried out for more than 40 years. By present, many works in periodical issues and several monographs have been published on the basis of the results obtained in numerous expeditions. In the present paper, the role of natural hybridization in plant systematics is demonstrated for Siberian birch species as example, and the necessity to have a distinct notion of hybridization processes over large territories that include the ranges of contacting species is stressed. It is a hopeless matter to solve the problems of systematics studying only small local populations.