Erythrina

Erythrina is a genus of trees, shrubs and suffrutices in the Fabaceae or pea family. They grow enlarged underground rootstocks. The plants are usually armed with prickles and variably hairy. The trees of this genus are often called coral trees.

The deciduous leaves are pinnately trifoliolate. The leaves have stipules that fall early, and the leaflets have paired glands at the base.

The inflorescences are many-flowered racemes growing at stem-tips, less often from leaf axils, arriving before or with the annual leaves. The inflorescences often look like a dense, triangular whorls. The deciduous bracts are usually hairy. The floral parts occur in fives. Many species bear bright, scarlet red or orange flowers. The generic name, Erythrina, is derived from the Greek word erythros meaning red, referring to the common flower colour. Calyces have narrow to bell-shaped tubes. They are sometimes two-lipped, cleft nearly to the base or hairy.

The short-clawed banner petals are folded down the centre and sickle-shaped. The single banner of each flower is much bigger than the wing or keel petals and envelops them. The frequently curved wing petals also have short claws and sometimes basal ears.  The keels or carinas each consists of two fused petals, sometimes eared at the base.

The reproductive structures of the flowers, dependent on pollination, are situated in these keels. The stamens are united at the base in a tube of variable length, the uppermost stamen of each flower free. The stalked ovary is linear and hairy. It contains numerous ovules. The cylindrical style is incurved, the stigma small at its tip. 

The usually sickle-shaped fruit pod is nearly cylindrical or constricted between seeds and armed with prickles. The smooth, brown, orange or red seeds are ellipsoid, most with a black patch where it was attached to the funicle.

There are about 130 Erythrina species worldwide in warm regions, nine of which occur in southern Africa.

Some Erythrina seeds, commonly known as lucky beans, are threaded on string as necklaces. Truncheons of some larger Erythrina trees are used as fence poles. Some take root, creating living fences. Many birds, including sunbirds, weavers, starlings and bulbuls consume nectar from the flowers. Barbets and woodpeckers hollow out dead branches of some of the soft wood Erythrina trees for nesting. Some butterflies and moths feed on the leaves. Several species are popular garden plants.

The plant in picture is Erythrina acanthocarpa (Leistner, (Ed.), 2000; Coates Palgrave, 2002; Wikipedia; https://pza.sanbi.org).