Vaccinium is a genus of shrubs in the plant Family Ericaceae including the cranberry, blueberry, bilberry or whortleberry, lingonberry or cowberry, and huckleberry. The genus contains about 450 species, which are found mostly in the cooler areas of the Northern Hemisphere, although there are tropical species from as widely separated areas as Madagascar and Hawai'i. The plants prefer heath landscapes, as well as open forests. The name Vaccinium was used for a type of berry (probably the bilberry V. myrtillus) in classical Latin, but its ultimate derivation is obscure; it has nothing to do with vaccinum "of or pertaining to cows", but may be a corruption of Latin bacca, berry (OED).
The taxonomy is complex, and still under investigation. A number of the Asian species are more closely related to Agapetes than to other Vaccinium species. A second group includes most of Orthaea and Notopora, at least some of Gaylussacia (huckleberry), and a number of species from Vaccinium, such as Vaccinium crassifolium. Other parts of Vaccinium form other groups, sometimes together with species of other genera.
A classification which predates molecular phylogeny divides Vaccinium into subgenera, and several sections:Subgenus Oxycoccus: The cranberries, with slender, trailing, wiry non-woody shoots and strongly reflexed flower petals. Some botanists treat Oxycoccus as a distinct genus.