The class Rhamno-Prunetea includes European temperate vegetation dominated by low or tall shrubs or fast-growing pioneer trees in mesic to dry habitats. Characteristic shrub genera include Cornus, Cotoneaster, Crataegus, Euonymus, Ligustrum, Lonicera, Prunus, Pyrus, Rhamnus, Ribes, Rosa, Rubus, Sambucus, Sorbus and Viburnum, but isolated or stunted individuals of trees or neophytic shrubs may also occur. The herb layer is composed of a mixture of species typical of dry and mesic grasslands, ruderal herbaceous vegetation, forest clearings and forest herb layers. Some shrub communities may be natural, especially those on cliff ledges and at forest edges in the forest-steppe regions, but most of them are secondary vegetation on disturbed sites or stages of secondary succesion on abandoned meadows or pastures. We assign to this class also Robinia pseudoacacia groves, which possess forest structure in most cases, but their species composition and dynamics share considerable similarities with scrub vegetation.