The border cultivars of Geum

摘要

GEUM, A GENUS in the Rosaceae, comprises about 40 species distributed around the world in cold and temperate areas. The most recent revision (Bolle 193.3) recognised 36 species. The UK has two native species - G. urbanum (herb Bennet), now regarded as a weed but valued in mediaeval times, and G. rivak (water avens). Their natural hybrid, G. x intermedium, is a textbook example of a wild hybrid exhibiting intermediate morphology and habitat requirements.