The class Stellarietea mediae includes vegetation of frequently or recently disturbed sites with nutrient-rich soils and a preponderance of annual herbs. It occurs either as weed vegetation on arable land or as ruderal vegetation in human settlements and other disturbed places. It is mainly composed of annual plants. Stellarietea mediae vegetation expanded in central Europe with the advent of Neolithic agriculture. Many species typical of this vegetation are archaeophytes which were introduced mainly from the Near East and Mediterranean during prehistoric period. Species composition of this vegetation was changing with changes in agrotechniques and management of human-made habitats. In modern times several neophytes spread in this vegetation. Today this class encompasses large diversity of plant communities ranging from species-poor monodominant stands to species-rich weed communities in less intensively managed arable fields or gardens.