This is a cosmopolitan genus, occurring in alpine habitats of temperate regions of Asia, Europe and the Americas. Some species also occur in northwest Africa, eastern Australia and New Zealand. They consist of annual, biennial and perennial plants. Some are evergreen, others are not.
Gentians have opposite leaves that are sometimes arranged in a basal rosette, and trumpet-shaped flowers that are usually deep blue or azure, but may vary from white, creamy and yellow to red. Many species also show considerable polymorphism with respect to flower color. Typically, blue-flowered species predominate in the Northern Hemisphere, with red-flowered species dominant in the Andes (where bird pollination is probably more heavily favored by natural selection). White-flowered species are scattered throughout the range of the genus but dominate in New Zealand. All gentian species have terminal tubular flowers and most are pentamerous, i.e. with 5 corolla lobes (petals), and 5 sepals, but 4-7 in some species. The style is rather short or absent. The corolla shows folds (= plicae) between the lobes. The ovary is mostly sessile and has nectary glands.
Many gentians are difficult to grow outside their wild habitat, but several species are available in cultivation. Gentians are fully hardy and like full sun or partial shade, and neutral to acid soil that is rich in humus and well drained. They are popular in rock gardens.
According to Pliny the Elder, Gentian is an eponym of Gentius (180-168 BC), the King of Illyria, said to have discovered its healing properties. Some species are of medicinal use and their roots were harvested for the manufacture of tonic liquor, for instance in France "Suze" or similar liquors. Gentian is also used as a flavouring, for example in bitters, and the soft drink "Moxie" which contains "Gentian Root Extractives".