Allyssum incanum, hoary alyssum, hoary alison, false hoary madwort, hoary berteroa
Description: annual or perennial
Place of origin: east central Europe and western Asia
Urban habitat: commonly found in disturbed open sites with sandy or gravelly soils, along roads, trails, lawns, vacant lots; tolerates drought conditions.
Ecological function: disturbance-adapted colonizer of bare ground; food and habitat for wildlife.
History: Berteroa incana was likely introduced into North America as a contaminant of clover and alfalfa seed. It is currently found throughout North America where it is widely considered a noxious weed. It can be toxic to horses when grazing in hay fields contaminated with it. Seeds can remain dormant but viable for up to 9 years.