Barbarea intermedia Bor. en Barbarea verna (Mill.) Aschrs. in Nederland

During a revision of herbarium material of the genus Barbarea, it became apparent that Barbarea intermedia Bor. is much more common in the Netherlands than was supposed. It is probably a native rather than a casual species although it may have been introduced long ago. Barbarea verna (Mill.) Aschrs., usually thought of as a rare native species, appears to be merely a casual in the Netherlands.