Scientific Note: Thlaspi alliaceum L. (Brassicaceae): An Exotic, Invasive Annual Rapidly Spreading in Pennsylvania, Together with the First Collections of This Species in North America


Allison W. Cusick

Additional Authors:


March 2015


Scientific Note Brassicaceae, distribution records, nonnative species, Pennsylvania, Thlaspi

ABSTRACT Thlaspi alliaceum L. (Brassicaceae) is a weedy, annual, European species of ruderal habitats known from 14 states in the eastern USA. It first was collected in North America in 1947 in Pennsylvania, although most references cite a 1956 collection from North Carolina. The species now has been vouchered in 23 Pennsylvania counties. Populations frequently consist of thousands of individuals. Despite its frequency, Thlaspi alliaceum is underreported in published works on the Pennsylvania flora.