[Cal-IPC] Invasiveness: Descurainia sophia (flixweed) is an annual or biennial (family Brassicaceae) found throughout California along roadsides, in agricultural fields, disturbed desert areas, scrub, grasslands and woodlands. It is most common in the northeastern region, particularly in the Great Basin. It tends to prefer well-drained sandy or stony soils. Flowering flixweed plants can be toxic to cattle when they are eaten over a long period of time. It produces abundant seed, which can be spread by soil or water movement, and by clinging to animals, humans and vehicle tires, but its rate of spread is relatively slow except in disturbed areas. Flixweed may invade recently disturbed areas and then become less dominant as native species become re-established. (link added by Mary Ann Machi)

[www.fs.usda.gov] Europe & Africa Native: Herb sophia is native to Europe and northern Africa [133]. It probably arrived in North America in the mid-1800s as an impurity in crop seed, and was widespread by the 1920s [103]. It now occurs in 48 states, excluding Alabama and Florida [72]. Its distribution extends south to Baja California, and as far north as 70o N latitude in Greenland, Alaska, and Canada. It occurs throughout Canada except Labrador and eastern Nunavut [69,72,133,147]. Plants database provides a distributional map of herb sophia in the United States and Canada. Herb sophia is also introduced in South America, Asia, southern Africa, and New Zealand [69,88]. (link added by Mary Ann Machi)