This monotypic genus is a common weedy annual of Europe that is naturalized in northeastern states, but does not seem to be spreading within Ky. or more southeastern states (W). The few records here date only from 1893 (Pr) to 1947 (or perhaps an unverified record in 1975). Aethusa is somewhat toxic to mammals when fresh, involving a polyene "aethusin" (Hotti & Rischer 2017).