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 zeyheri is a strange plant. Most of it is underground! It is a very low growing, deciduous, suffruticose (woody stem only extends a few inches above ground) shrublet not reaching more than 300-600 mm in height. Shoots form every year from the underground stems and die down in winter. This plant has an enormous caudex or underground rootstock in which it stores food. The large leaves are compound, with three leaflets, and covered with large, recurved prickles on the midrib and larger side veins. They are light green and covered by rough hairs. The leaves are long-stalked and increase in size as the summer progresses. It produces showy scarlet flowers forming upright inflorescences on long stalks over several weeks in summer (October to January). The fruit is a smooth black pod with a few orange-red seeds. It is said to have medicinal uses. In the colonial days, asthma sufferers smoked the underground portion of this plant.