The history and distribution of the bulbil-bearing Ficaria verna subsp. verna (Ranunculaceae) in Britain

The distributions of the subspecies of Ficaria verna Huds. are under-recorded in Britain, but published county Floras indicate that subsp. verna is an introduction in some areas and is increasing in many areas. This evidence is examined and a hypothesis to account for the observed patterns is tested against an analogy with Allium paradoxum (M. Bieb.) G. Don in Berwickshire where the author has personally observed colonisation over forty years. The results suggest a link between the recent increase in Ficaria verna subsp. verna and the nineteenth century expansion of the horticultural trade. Earlier waves of colonisation are suspected but not substantiated.