Erythrina is a genus of flowering plants in the pea family, Fabaceae. It contains about 130 species, which are distributed in tropical and subtropical regions worldwide. They are shrubs or trees, growing up to 30m in height. They are popular bonsai subjects and are popular choices for bird gardeners. The generic name is derived from the Greek word erythros, meaning red, referring to the flower colour of certain species. Particularly in horticulture, the name coral tree is used as a collective term for these plants. “Flame trees” is another vernacular name, but may refer to a number of unrelated plants as well. Many species of Erythrina have bright red flowers, and this may be the origin of the common name.

Erythrina acanthocarpa commonly known as Tambookie Thorn in English and Tamboekiedoring in Afrikaans is a very attractive shrub with striking red and green flowers. This attractive shrub occurs naturally in the Queenstown district in the Eastern Cape Province, South Africa, an area once known as Tambukiland (hence tambookie thorn). The plant is endemic to this and possibly adjacent districts and occurs nowhere else in the world. In its natural habitat, the plants often form low thickets and covered large tracts of land. Early travellers reported these areas to be a blaze of red during spring and early summer when it is flowering, but sadly the plant is no longer as common. The tambookie thorn is a much branched, deciduous, thorny shrub reaching up to 2m in height. The striking flowers are scarlet with the upper petal edged with green and are held in heads up to 10cm long and about 12cm wide. The leaves are compound with three leaflets and bear numerous hooked, sharp, purplish-black prickles. The brown pods are up to 12cm long, constricted between the seeds and are armed with prickles (hence the specific name “acanthocarpa”). The seeds are brown and larger than those of other local Erythrina species. They are reportedly used as a magical charm against evil. An interesting feature of this plant is its greatly enlarged underground rootstock or caudex. There are reports dating from the 1860s that the succulent underground “root” is extremely light when dry, and in this state was sometimes made into light summer hats, hence the name pith helmets.