FIELD STUDIES OF SIX SOUTHERN AFRICAN SPECIES OF ERYTHRINA

The Erythrina species of southern Africa range from small suffrutices to tall trees, up to 24 m in height. One species is a geophyte. All possess brightly colored flowers in the scarlet, crimson and orange range, while some species produce a few plants bearing cream or almost white, pink, and a variety of red flowers. All species discussed appear to produce a fair to plentiful supply of nectar, and, from observation, several species of indigenous and exotic birds are the pollinating agents. The two species of Erythrina sect. Humeanae, E. humeana and E. zeyheri, which have flowers that resemble those of the American hummingbird-pollinated species of the genus, are visited by sunbirds and white-eyes, whereas larger birds are also frequent at the flowers of the other species. The means of distribution of the usually brightly colored and poisonous seeds is unknown as yet. Some of the southern African Erythrina species have been known in cultivation for a considerable period of time. Erythrina humeana was grown in Europe more than 150 years ago, while one species, possibly E. caffra or E. lysistemon, has been grown on the island of St. Helena for perhaps that length of time. Both these species grow easily from truncheons, and one can often see in southern Africa lines of such trees where they were once planted as protective fences or fence posts. That so little is known of the biology of these species is therefore surprising. The following observations have been compiled from casual observations by the authors and are supplemented by information gleaned from various books (Acocks, 1975; Batten & Bokelmann, 1966; Coates Palgrave, 1977; Gledhill, 1969; Hennessy, 1972) and that supplied by Mrs. E. F. Hennessy. Careful study may, quite possibly, alter some of these observations.