Carrichtera is a monotypic genus of flowering plants in the mustard family (Brassicaceae) containing the single species Carrichtera annua, commonly known as Ward's weed. It is an annual herb with white to yellow flowers and hairy, lobed leaves. The species is native to Macaronesia, North Africa, Western Asia (east to Iran and Saudi Arabia), and parts of southern Europe including Portugal and Greece. It has been introduced to Italy, Japan, Australia, New Zealand, and California, where it is considered invasive. In California, it is found in the south coast ranges, favoring grasslands, scrub, and chaparral habitat. It reproduces by seed only, with seeds dispersed by foraging animals, vehicles, agricultural activities, and humans. The California Invasive Plant Council rates it as Moderate — Alert, and the California Department of Food and Agriculture rates it as Category A (limited distribution with potential for eradication or containment).
Distribution
Carrichtera is native to Macaronesia, North Africa, and Western Asia east to Iran and Saudi Arabia, with native populations also in Portugal and Greece. It has been introduced and is considered invasive in Italy, Japan, Australia, New Zealand, and California, where it is established in the south coast ranges.
Ecology
Carrichtera annua is an annual that favors grasslands, scrub, and chaparral habitat. It reproduces by seed only, with dispersal via foraging animals, vehicles, agricultural activities, and human activity. In California, it is rated as a moderate-impact invasive species with an Alert designation due to its limited but expanding distribution.
