Viola (Pansy, Violet, Heartsease)

This well-known and much loved genus of annuals, perennials and subshrubs consists of as many as 500 species, found in most temperate regions of the world including high mountains of the tropics, though with the greatest concentrations of species in North America, the Andes and Japan. Most are creeping plants, either deciduous or evergreen, with slender to thick rhizomes and leaves most often kidney-shaped or heartshaped, though in some species they are divided into narrow lobes. Flowers of wild species are seldom more than 1 in across and characteristically have 3 spreading lower petals and 2 erect upper petals, with a short nectar spur projecting to the rear of the flower. Many species also produce cleistogamous flowers, with smaller petals that do not open properly, and able to set seed without cross-pollination. A few Eurasian species have been hybridized extensively to produce the garden pansies, violas and violettas, with showy flowers in very bright or deep colors; these are nearly always grown as annuuals, though potentially some are short-lived perennials.