About 250-300 species in Eurasia and South Africa, 100 in the FSU, mainly in the Caucasus, also in the European regions and in the Far East. Some Russian species are known in horticulture (e.g. D. chinensis L., D. campestris Bieb., D. carthusionorum L. and D. superbus L.). A number of species have been investigated in St. Petersburg. They are very ornamental and long-flowering plants.