Fumaria muralis Sond. ex W.D.J. Koch (W-Eur., N-Afr.) – A rare but much increasing and probably still overlooked alien. Probably first collected in the port of Antwerpen in 1915. Soon afterwards also seen in Gavere (ditch) and subsequently in Ougrée (in a potato field) and in Ranst, twice in 1941. However, all of these records long remained unidentified or erroneously identified. In the beginning of the 1950’s Fumaria muralis was finally recognized and from then onwards more frequently seen but still rare, for instance in Tervuren (1952) and Sint-Idesbald (1954-1957). The naturalization and spread of Fumaria muralis clearly is a recent phenomenon (compare with Verloove 2002). According to Ronse (2006) the number of records dramatically increased from the 1970’s onwards. At that time rather widespread already at least locally, for instance, around Hannut (garden weed, waste land, former railway tracks) (Lebeau 1977). Today it is locally no longer rare and in some regions an undesirable weed in agricultural fields (although much less frequent in Wallonia).
Fumaria muralis is now found in a wide range of habitats. Naturalized populations are chiefly found in agricultural fields but it has been recorded also on pond margins, in coastal dunes, on rough ground and dumps, etc.
Residence status of Fumaria muralis in Belgium is obscure. It is here accepted as a non-native species (following Lawalrée 1956a and Lambinon & Verloove 2012) but Belgium seems to fall within its native range and it is considered native in most neighbouring areas. It apparently was long overlooked. On the other hand, its recent expansion could point to behaviour that usually is associated with non-native species.
Fumaria muralis itself also is a variable species. Belgian records are ascribed to subsp. boraei (Jord.) Pugsley (syn.: F. boraei Jord.), by far the most widespread taxon. Two additional taxa (see Stace 2010) have become nearly extinct in the British Isles and are rather unlikely to occur in Belgium. Some Belgian plants, however, are reminiscent of subsp. muralis. Stace l.c. stressed that recognition of subspecies is no longer feasible since so many hard-to-distinguish variants occur, some even tending towards Fumaria bastardii Boreau. For that reasons, Fumaria muralis is here accepted as a collective species, including numerous variants.
Selected literature:
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.
Lawalrée A (1956a) Fumariaceae. In: Robyns W. (ed.), Flore Générale de Belgique, vol. 2, fasc. 2. Jardin Botanique de l’Etat, Bruxelles: 141-159.
Lebeau J. (1977) Apparition en Hesbaye de Fumaria muralis Sond. ex Koch subsp. boraei (Jord.) Pugsley. Nat. Mosana 30(1): 42.
Ronse A. (2006) Fumaria muralis. 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: 412.
Sell P.D. (1989) The Fumaria bastardii Boreau/F. muralis Sonder ex Koch complex in the British Isles. BSBI News 51: 24-26.
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.
Verloove F. (2002) Ingeburgerde plantensoorten in Vlaanderen. Mededeling van het Instituut voor Natuurbehoud n° 20: 227 p.
Walsh N.G. (1992) Lectotypification of Fumaria muralis Sond. ex Koch (Fumariaceae). Muelleria 7: 495-496.