Taeniatherum caput-medusae (L.) Nevski var. caput-medusae (syn.: T. asperum (Simonk.) Nevski, Elymus caput-medusae L., Hordeum caput-medusae (L.) Coss. et Durieu) (Euras.) – A very rare and ephemeral alien, mostly associated with wool and grain. Probably first recorded as a wool alien in the valley of river Vesdre in 1911. In 1947 seen in abundance (and even claimed as naturalised!) on a building site in Antwerpen without obvious vector of introduction (De Langhe 1976). The most recent records are obviously related with grain importation: Taeniatherum caput-medusae was collected on a grain dump in Bilstain in 1954 and on several occasions in road verges in the port of Gent in 2011 (see also: http://waarnemingen.be/waarneming/view/54931966).
A closely related taxon, var. crinitum (Schreb.) C.J. Humphries (syn.: T. crinitum (Schreb.) Nevski, Hordeum crinitum (Schreb.) Desv.), was claimed from Belgium (Lambinon & al. 2004), apparently without obvious source.
Literature:
De Langhe J.E. (1976) Adventices nouvelles pour la flore belge. Bull. Soc. Roy. Bot. Belg. 109: 25-27.
Lambinon J., Delvosalle L., Duvigneaud J. (avec coll. Geerinck D., Lebeau J., Schumacker R. & Vannerom H. (2004) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Cinquième édition. Jardin botanique national de Belgique, Meise: CXXX + 1167 p.