Erythrina /ˌɛrɪˈθraɪnə/[3] 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 trees, with the larger species growing up to 30 m (98 ft) in height. The generic name is derived from the Greek word ερυθρóς (erythros), meaning "red", referring to the flower color of certain species.[4]
Particularly in horticulture, the name coral tree is used as a collective term for these plants. Flame tree 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. However, the growth of the branches can resemble the shape of sea coral rather than the color of Corallium rubrum specifically, and this is an alternative source for the name. Other popular names, usually local and particular to distinct species, liken the flowers' red hues to those of a male chicken's wattles, and/or the flower shape to its leg spurs. Commonly seen Spanish names for any local species are bucaré, frejolillo or porotillo, and in Afrikaans some are called kafferboom (from the species name Erythrina caffra). Mullumurikku is a widespread name in Kerala.
Not all species of Erythrina have bright red flowers; the Wiliwili (E. sandwicensis) has extraordinary variation in its flower colour, with orange, yellow, salmon, green and white all being found within natural populations. This striking color polymorphism is also found in Erythrina lysistemon and Erythrina caffra.
All species except the sterile hybrids E. × sykesii and E. × bidwillii have legume-type fruit, sometimes called pods, containing one or more seeds. The resilient buoyant seeds are often carried by the sea for large distances and are commonly called "sea beans".
Erythrina leaves are used as food plants by the larvae of some Lepidoptera species including the swift moth Endoclita damor and the woolly bears Hypercompe eridanus and Hypercompe icasia. The mite Tydeus munsteri is a pest on the coastal coral tree (E. caffra).
Many birds visit the nectar-rich Erythrina flowers. In the Neotropics, these are usually larger hummingbirds, for example the swallow-tailed hummingbird (Eupetomena macroura) and the black-throated (Anthracothorax nigricollis) and green-breasted mangos (A. prevostii) – though they seem not to be especially fond of E. speciosa at least, which they visit rather opportunistically. In Southeast Asia, the black drongo (Dicrurus macrocercus) which usually does not eat nectar in quantity has been observed feeding on E. suberosa flowers, and mynas and of course more specialized nectar feeders also utilize coral tree flowers. Lorikeets such as the collared lory (Phigys solitarius) and the possibly extinct New Caledonian lorikeet (Charmosyna diadema) are known to consume (or have consumed) large amounts of Erythrina nectar.