Sisymbrium volgense
Sisymbrium volgense Bieb. ex E. Fourn. (SW-Russia) – A very rare, locally naturalised alien. First discovered at the railway station of Quaregnon-Wasmuel in 1953 but not confirmed lately. Known since at least 1974 from a slope of an old mill in Oud-Turnhout (at least 1600 specimens in the 1970’s but by now much reduced; Verloove 2002). Finally also discovered on a talus of a railway track near the port of Gent in 1996 and subsequently further spreading in the surroundings on waste land.
Sisymbrium volgense is a rhizomatous perennial and thus forms dense stands. Curiously, ripe fruits are rarely (if at all) produced. It is a rather unshowy, Brassica-like plant that could easily pass unrecorded. Its perennial life-form, slightly glaucous foliage, tiny yellow flowers and often undeveloped fruits are diagnostic features.
Selected literature:
Brennenstuhl G. (2016) Sisymbrium wolgense M. Bieb. ex E. Fourn. im Stadtgebiet von Salzwedel (Altmark). Florist. Rundbr. 50: 120-126.
Clement E.J. (1979) Sisymbrium volgense Bieb. ex E. Fourn. in Britain. Watsonia 12: 311-314.
Jehlík V. (1981) Chorology and ecology of Sisymbrium volgense in Czechoslovakia. Folia Geobot. Phytotax. 16(4): 407-421.
Oprea A. and Sîrbu C. (2010) Sisymbrium volgense (Brassicaceae) in the flora of Romania. Analele Universităţii din Oradea - Fascicula Biologie 27(2): 296-299. [Available online at: http://core.kmi.open.ac.uk/display/861901]
Shaw J.M.H. (1995) Sisymbrium volgense: new to Derbyshire. BSBI News 68: 43.
Verloove F. (2002) Ingeburgerde plantensoorten in Vlaanderen. Mededeling van het Instituut voor Natuurbehoud n° 20: 227 p.