Trifolium rubens L. Leguminosae. [Note the Family Leguminosae is preferred over Family Fabaceae as the former allows all the legumes to be in one Family and not three - one Family being the current consensus among botanists]. Red Feather Clover. Distribution: Europe. The white clover, Trifolium repens, is listed as a treatment for arthritis by Linnaeus (1782). This and Trifolium pratense, Red Clover, are the ones most used for pastures. All the clovers have root nodules which fix nitrogen from the air into the soil so have an important role in ensuring soil fertility. Trifolium rubens has the same nitrogen fixing ability, and is used as an ornamental garden plant where it still acts to improve fertility. Photographed in the Medicinal Garden of the Royal College of Physicians, London.