Ragweeds (Ambrosia l.) in britain

Abstract

The occurrence and ecology of three species of Ragweed (Ambrosia L.) in Britain is described. Ambrosia artemisiifoiia L. is the commonest species and is most often introduced with bird seed, but does not persist probably due to climate limitation of seed production and germination. A. psilos- tachya DC. is rarely established in sandy places. A. trifida L. is an uncommon introduction which also docs not persist. Ragweed pollen was regularly recorded in Britain in 1992. Under conditions of global warming, it is likely that A. artemisiifoiia will become established in Britain and could cause widespread hay fever. © 1994 Scandinavian University Press.