Geranium macrorrhizum

4. Geranium macrorrhizum L. (incl. G. xcantabrigiense Yeo, = G. dalmaticum (Beck.) Rech. f. x G. macrorrhizum) (mountains of SE-Europe) – A rare but increasing, locally naturalised escape from cultivation. Probably first collected on old walls in Liège in 1821. Doubtlessly best known from Roly (Bois Jean Mouton) where it is naturalised since at least 1851 on shady calcareous slopes, along with several other relics of former cultivation (in the vicinity of a cave). Furthermore known from rather few localities, for instance from old walls near a gravel pit in Anthisnes (at least between 1899 and 1940). Also (formerly) recorded in Anhée, Nessonvaux, Plainevaux, Theux and Visé but perhaps always ephemeral or only temporarily persistent. Sometimes seen as an escape in the vicinity of gardens, for instance in Vottem in 1990. Recently also recorded on a quay wall in the (old) port of Antwerpen. Geranium macrorrhizum at present is one of the more frequent species in cultivation. It is often discarded and easily persists in woodland margins, under shrub,… Recent records are available, for instance, from Aartrijke, Brugge and Oostduinkerke.

A hybrid with Geranium dalmaticum (G. xcantabrigiense) is also sometimes cultivated nowadays. Some recent records might in fact represent this hybrid. It usually has smaller and more glossy leaves that are nearly lobed to base. It was recorded, for instance, in a former sandpit-dump in Flobecq (La Houppe) since 2009. In 2010 furthermore seen on the verge of a garden in Mol (see also: http://waarnemingen.be/waarneming/view/50829504). Probably overlooked elsewhere. All these taxa are easily recognised by their long-exserted stamens.