3. Rudbeckia hirta L. (syn.: R. serotina Nutt.) (N-Am) – A rare and usually ephemeral alien, mostly an escape from cultivation. Sometimes persistent for some time or very locally more or less naturalised. First recorded as a seed alien in a clover field in Wavreille in 1926. Subsequently found in identical circumstances in Lierneux and near Jamoigne in 1949. Formerly naturalised in abundance in a fallow field between Jamoigne and Prouvy, at least in the 1940’s and 50’s. Most recent records are from dumps, ground heaps and are obviously associated with garden deposits. Such records usually prove to be rather ephemeral. Recorded in abundance in ruderalised grassland near Nivelles (Henrion 1999). Rudbeckia hirta is usually found in dry, sun-exposed locations.
Rudbeckia hirta is a very variable species, especially with regard to leaf shape, flower colour and life form. It is usually biennial or perennial but often grown as an annual in western Europe. Ligular florets are entirely yellow, yellow with a marroon base or nearly entirely marroon. Leaves are most of the time entire but can be slightly lobed as well. A Belgian record of Rudbeckia bicolor Nutt. (syn.: R. hirta var. pulcherrima Farwell) also belongs here (see Delvosalle 1953).
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Selected literature:
Adolphi K. (1995) Neophytische Kultur- und Anbaupflanzen als Kulturflüchtlinge des Rheinlandes. Nardus 2: 272 p.
Delvosalle L. (1953) Quelques adventices nouvelles pour la Belgique. Bull. Soc. Roy. Bot. Belg. 85: 297-303.
Henrion E. (1999) De surprise en surprise en parcourant l’ancien circuit automobile de Nivelles (F4.45). Adoxa 24-25: 10.