Relevance and purpose. The Russian geobotanical science has a profound tradition of studying the vegetation cover heterogeneities. However, the number of studies on the mosaics in complexly organized coniferous-deciduous forests is very limited, and there is high ambiguity in the obtained results. In addition, there has appeared a need to resolve the “terminological issue”. The aim of this study was to assess the vegetation cover mosaics of widespread forest phytocenoses in the Moskva-Oka Plain. Material and methods. We present a review of publications on the intracenotic heterogeneity of forest cover and make an attempt to systematize the existing terminology. The field studies were carried out on the territory of the Valuevsky forest park (Novomoskovsky AO, Moscow) using classical geobotanical methods. The acquired data was analyzed with various modern methods of statistical data analysis. Results and conclusions. The obtained results indicate that differences in vegetation are much more pronounced at the level of phytocenoses than at the level of microgroups. The most powerful edificatory effect of spruce has been confirmed. We identified the following reasons that determine the weak differentiation of vegetation at the level of microgroups: the co-influence of neighboring microgroups, the lack of individual trees’ impact duration for a noticeable transformation of vegetation, and legacies in the structure and species composition of previous states over a long period of time.