Barbarea australis is a morphologically and ecologically typical Barbarea

Barbarea

Barbarea is a genus of about 22 species of flowering plants in the family Brassicaceae, native to temperate regions of the Northern Hemisphere, with the highest species diversity in southern Europe and southwest Asia.They are small herbaceous biennial or perennial plants with dark green, deeply...

species with an unusual distribution: it is an endemic and threatened species from Tasmania

Tasmania

Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

. The leaves have a large end-lobe and only few side lobes, much like the leaf-shape of Barbarea stricta and Barbarea orthoceras

Barbarea orthoceras

Barbarea orthoceras is a species of flowering plant in the mustard family known by the common name American yellowrocket. It is native to North America, including much of Canada and the western United States, as well as parts of Asia. It grows in moist areas such as meadows and riverbanks...

. With regard to defence chemicals (glucosinolates), it is similar to other members of the genus.