This alliance includes stands of medium-tall winter-annual grasses, e.g. Bromus sterilis. B. tectorum and Hordeum murinum; it includes some ancient, archaeophytic, ruderal vegetation types. These species rapidly colonize recently disturbed or exposed habitats around construction sites, in settlements, on roadsides, at the margins of shrubberies or on the tops of walls. The phenological optimum of this thermophilous and drought-adapted vegetation type is in spring.