Vinca major - double flowered

Vinca major L. Apocynaceae double-flowered Large Periwinkle. Distribution: Western Mediterranean. A noxious weed in may countries, and invasive even in London gardens. Vincamine, a chemical extracted from Vinca minor is available in the USA as a dietary supplement but also as a drug to increase cerebral blood flow. It is not available in the UK. Photographed in the Medicinal Garden of the Royal College of Physicians, London.