926 Armoracia rusticana (Lam.) Gaertn., Mey. & Schreb.

This useful plant probably originates from S. Russia (see the map). It is widely cultivated and escapes easily from gardens and is partly naturalized in, for instance, C. and W. Europe, Ethiopia, parts of Asia, N. and S. America and New Zealand. The closely related A. sisymbrioides (DC.) Cajand. in C. Asia is mapped separately. With its present distribution A. rusticana belongs to the discontinuous circumpolar plants (Hultén, Circumpol. Il, p. 194 and map 185).