Conringia Heist. ex Fabr.
Conringia is a genus of six species. All are native to Eurasia but none naturally occurs in Belgium (Lambinon & Verloove 2012). Its center of diversity obviously lies in Turkey where all species occur (Hedge 1965). One species, Conringia orientalis, has become a (sub-) cosmopolitan weed. Three species have been recorded so far as aliens in Belgium, nearly exclusively as grain aliens, but only two in recent times.
1 Siliqua tetragonous, each valve with a single distinct vein, not torulose. Petals creamy-white, never with violet veins running to apex === Conringia orientalis
Siliqua flattened, without veins, distinctly torulose. Petals pale yellow or white with violet veins running to apex === C. planisiliqua
Additional alien: Conringia austriaca (Jacq.) Sweet (SE- and SC Eur., grain alien).
Literature:
Hedge I. (1965) Conringia. In: Davis P.H. (ed.), Flora of Turkey and the East Aegean Islands, vol. 1. University Press, Edinburgh: 275-278.
Lambinon J. & Verloove F. (avec coll. Delvosalle L., Toussaint B., Geerinck D., Hoste I., Van Rossum F., Cornier B., Schumacker R., Vanderpoorten A. & Vannerom H.) (2012) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Sixième édition. Jardin botanique national de Belgique, Meise: CXXXIX + 1195 p.
Schulz O.E. (1923) Conringia. In: Engler A. (ed.), Das Pflanzenreich 84(IV.105). Engelmann, Leipzig: 84-94.