Fumitory, also known as carrot weed, is the widely used name for several species of Fumaria. Worldwide there are about 50 species of which eight are recorded in Australia.

Fumitory is an autumn and winter growing annual, glabrous (hairless) herb with a semi-erect climbing habit. Leaves are alternate, divided, deeply lobed and light green to bluish-green. Stems are irregularly five-angled, are brittle, may be reddish and contain a watery, greenish latex. The flowers are arranged in racemes and colour ranges from white to mauve depending on species. The plants vary greatly in their morphology depending on the growing conditions but also within species, particularly for F. bastardii. This variability leads to difficulty in the correct identification of the species.