Gesneriaceae, the gesneriad family,[3][4] is a family of flowering plants consisting of about 152 genera and ca. 3,540 species[5] in the tropics and subtropics of the Old World (almost all Didymocarpoideae) and the New World (most Gesnerioideae), with a very small number extending to temperate areas. Many species have colorful and showy flowers and are cultivated as ornamental plants.
The family name is based on the genus Gesneria, which honours Swiss naturalist and humanist Conrad Gessner.[6]
Most species are herbaceous perennials or subshrubs but a few are woody shrubs or small trees. The phyllotaxy is usually opposite and decussate, but leaves have a spiral or alternate arrangement in some groups. As with other members of the Lamiales the flowers have a (usually) zygomorphic corolla whose petals are fused into a tube and there is no one character that separates a gesneriad from any other member of Lamiales.[4] Gesneriads differ from related families of the Lamiales in having an unusual inflorescence structure, the "pair-flowered cyme", but some gesneriads lack this characteristic, and some other Lamiales (Calceolariaceae and some Scrophulariaceae) share it. The ovary can be superior, half-inferior or fully inferior, and the fruit a dry or fleshy capsule or a berry. The seeds are always small and numerous. Gesneriaceae have traditionally been separated from Scrophulariaceae by having a unilocular rather than bilocular ovary, with parietal rather than axile placentation.
"Gesneriaceae" is a conserved name (nom. cons.),[2] meaning that although alternative, less well used names for the family were published earlier, the International Code of Nomenclature for algae, fungi, and plants specifies this as the name to be used. It was published by Louis Claude Richard and Antoine Laurent de Jussieu in 1816.[1] In 1829, Barthélemy Dumortier divided the family into two tribes, based on the number of stamens.[7] However, the only genus he placed in his two-stamen tribe, Columellia, is now placed in the separate family Columelliaceae.[8] Dumortier's publication has been treated as the first for the family by some sources.[9]
Botanists who have made significant contributions to the systematics of the family are George Bentham, Robert Brown, B.L. Burtt, C.B. Clarke, Olive Mary Hilliard, Joseph Dalton Hooker, William Jackson Hooker, Karl Fritsch, Elmer Drew Merrill, Harold E. Moore, Jr., John L. Clark, Conrad Vernon Morton, Henry Nicholas Ridley, Laurence Skog, W.T. Wang, Anton Weber, and Hans Wiehler.[citation needed] The Gesneriad Society is an international horticultural society devoted to the promotion, cultivation, and study of Gesneriaceae.[10]
From about 1997 onwards, molecular phylogenetic studies led to extensive changes in the classification of the family Gesneriaceae and its genera, many of which have been re-circumscribed or synonymized. New species are still being discovered, particularly in Asia, and may further change generic boundaries. A consensus phylogeny used to build classifications of the family in 2013 and 2020 is shown below (to the level of tribes). The family Calceolariaceae is shown as the sister to Gesneriaceae.[11][12]