Stock photography, photos: Vinca minor Stock photos of Vinca minor - Periwinkle. Periwinkle is the source for vincristine, a drug used for cancer treatment Photograph: © Humberto Olarte Cupas Click for a larger image and more information Keywords associated with this stock photo: Vinca minor, periwinkle, cancer, drug, treat, treatment, vincristine, pink, flower, plant, green, close up