Lepidium virginicum L. (N-Am.) – A rather common, more or less widely naturalised and increasing alien. First recorded in 1859 near a grain mill in Gent. Also seen in scattered other locations in the 19th century but rare and probably merely ephemeral. In the course of the 20th century increasingly recorded, apparently from a wide range of introduction vectors (grain, wool, ore, etc.).
At present most widely dispersed around the largest cities in Flanders (Antwerpen, Brussel, Gent,…) and in the Kempen (Verloove 2006c). Also frequently seen along railway tracks. Lepidium virginicum usually occupies gravelly, sun-exposed, slightly nitrophilous habitats: railway yards, gravel pits, waste land, urban habitats, etc.
Lepidium virginicum is closely related (and, according to some sources, possibly even conspecific; see Clement & Foster 1994, Stace 2010) with L. densiflorum. Both are still confused in Belgium. Al-Shehbaz & Gaskin (2010) referred to hybrids between these two species.
Selected literature:
Al-Shehbaz I.A. & Gaskin J.F. (2010) Lepidium. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 7. Oxford University Press, New York-Oxford: 570-595.
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Feder J. (1999) Zur Verbreitung von Lepidium virginicum L. in Niedersachsen und Bremen. Abh. Naturwiss. Ver. Bremen 44(2-3): 345-354.
Meissner H. (1950) Notizen über Wanderpflanzen. I. Lepidium densiflorum Schrad. und Lepidium virginicum L. Mitteilungen der Floristisch-soziologischen Arbeitsgemeinschaft N. F. 2: 77-93.
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.
Van der Ham R.W.J.M. (1981) De Virginische kruidkers, Lepidium virginicum L., in Limburg. Natuurhist. Maandblad 70(6-7): 101-105.
Verloove F. (2002) Ingeburgerde plantensoorten in Vlaanderen. Mededeling van het Instituut voor Natuurbehoud n° 20: 227 p.
Verloove F. (2006c) Lepidium virginicum. In: Van Landuyt W., Hoste I., Vanhecke L., Van den Bremt P., Vercruysse W. & De Beer D., Atlas van de flora van Vlaanderen en het Brussels gewest. Instituut voor Natuur- en Bosonderzoek, Nationale Plantentuin van België en Flo.Wer: 537.
Wasowicz P. & Rostanski A. (2009) The use of quantitative characters in determination of frequently misdiagnosed species within Lepidium L. sect. Dileptium (Brassicaceae). Acta Soc. Bot. Polon. 78(3): 221-227.