Davidsonia is a small genus of three rainforest tree species endemic to eastern Australia, placed in the family Cunoniaceae within the order Oxalidales. The genus is commonly known as Davidson's plum, a name that refers to the superficial resemblance of the fruit to European plums, though the two groups are not closely related.
All three species are trees found in subtropical to tropical rainforest conditions along the coast and ranges of Queensland and New South Wales. Davidsonia pruriens (Ooray or Queensland Davidson's plum) is the tallest, reaching up to 12 metres, with large clusters of fruit borne directly from the trunk and main branches (cauliflory). Davidsonia jerseyana (Davidson's plum or Mullumbimby plum) is a slender tree typically around 5 metres tall, native to lowland subtropical rainforests of New South Wales, and is the species most widely cultivated commercially. Davidsonia johnsonii (smooth Davidson's plum) has a spreading canopy and smooth leaves and is native to New South Wales and southeast Queensland.
The fruit of all species is drupaceous and plum-like, with a pruinose (waxy-bloomed) skin and deep red to burgundy flesh containing two flattened seeds. The flavour is distinctly sour, and the fruit is highly regarded in Australian gourmet bushfood cuisine, used in jams, wines, ice creams, and sauces. Small-scale commercial plantations in New South Wales and Queensland supply the market, primarily using D. jerseyana and D. pruriens. Both D. jerseyana and D. johnsonii are considered endangered in the wild.
Etymology
The genus Davidsonia was named after John Ewen Davidson, the person who claimed the land from which the tree was first botanically described. The genus was described by Ferdinand von Mueller (F.Muell.), the 19th-century German-Australian botanist.
Distribution
Davidsonia is endemic to eastern Australia, occurring in subtropical and tropical rainforests of Queensland and New South Wales. The species occupy coastal lowland and upland rainforest habitats within this range.
Ecology
All three species grow in rainforest environments in eastern Australia. Davidsonia jerseyana is associated with lowland subtropical rainforest in New South Wales. The fruit, produced in some species directly from the trunk or major branches (cauliflory in D. pruriens), is characteristic of rainforest tree species adapted to vertebrate dispersal.
Cultivation
Davidsonia jerseyana is the most widely cultivated species and is grown on small-scale plantations in New South Wales and Queensland to supply the gourmet bushfood market. Davidsonia johnsonii is not widely cultivated because its seeds are largely infertile; it is propagated vegetatively from cuttings or root division. Fruit from cultivated plants is used in jams, wines, ice creams, and sauces.
Conservation
Both Davidsonia jerseyana and Davidsonia johnsonii are considered endangered species in the wild. Despite this, D. jerseyana is widely cultivated, which has helped maintain availability of the species outside its natural habitat.
Cultural Uses
The fruit of all Davidsonia species is edible and sour, and has long been used as a bushfood. It is highly regarded in Australian gourmet cuisine and is processed into jams, wines, ice creams, and sauces. The genus is one of the better-known native Australian fruit genera used commercially in the bushfood industry.
