Luck in full colour

This week we introduce our new series, Local and lovely’. Learn about our natural heritage and the links between cultural and biological diversity with the SA National Biodiversity Institute.

Umsintsi the Coral Tree Name: Erythrinacaffra Thunb. Family: Fabaceae (legume or pod-bearing family) Common names: English: Coral tree Afrikaans: Koraalboom Xhosa:Umsintsi

Spring has sprung and so has our bright red-coloured coral tree. Enjoy its shade while gazing at its beauty!

E caffra is a medium-sized to large deciduous tree about 9-12m in height with spreading rounded crown. Under favourable conditions the tree reaches about 20m. tall. The bark of stem is grey in colour often with short sharp prickles or knobs. Leaves are trifoliate scattered or clustered at the ends of the twigs, unarmed and hairless; leaflets are egg-shaped (ovate) to elliptic, the top one is 80-60 x 80-180mm. The ones on the side are slightly smaller, without hairs and prickles.

Flowers are orange-scarlet, occasionally cream, dense, showy, hanging downwards in terminal raceme up to 100mm long, usually appearing before the new leaves; standard petal relatively short and broad, opening slightly to expose the stamens. Fruit is a cylindrical pod, up to 65mm long, dark coloured and deeply constricted between the seeds and with these constrictions frequently elongated, densely cottony hairs when young and becoming hairless when old. Seeds are bright red, elliptic with black spot at the point of attachment. Flowering from August to September.

You will find E caffra in coastal forest, often near rivers, from Humansdorp in the Eastern Cape to Port Shepstone in KwaZulu-Natal. It also grows along the Western Shores, Lake St Lucia, in swamp forest at North Maputaland and Inhaca Island.

How Erythrina caffra got its name

The Genus name Erythrina is derived from a Greek word erythros meaning “red” referring to the colour of the flowers. The Latin species epithet is derived from Caffraria; this genus comprises 130 species, which are distributed in tropical and subtropical regions worldwide.

Cultural links

Xhosa people name their calendar months according to the stars and plants that flower during certain months, eg July is known as eyeKhala because the aloes are flowering, and November as eyeNkanga, when African ragworts are flowering. September in the Xhosa calendar is known as eyoUmsintsi because the flowering of this tree is an indicator to Xhosa people to sow sorghum and maize. In Xhosa there is a proverb about the coral tree that says “Ukubambelela esebeni lomsintsi” which literally means “to hold on to the branch of coral tree”, that is to entertain false hope because the branches of the coral tree are deceptively brittle.

According the Kumbula Nursery website the various parts of the tree are used medicinally: the bark to treat sores, wounds, abscesses and arthritis; infusions of the leaves for toothache and earache; and decoctions of the roots for sprains. Traditional uses suggest antibacterial, anti-inflammatory and analgesic effects. The seeds of all Erythrinas are said to be poisonous. http://kumbulanursery. co.za/plants/erythrina-caffra

Seeds are commonly known as “lucky beans”. These beans represent luck and many people put these in their wallets, and some make charm necklaces and earrings. Coral tree wood is light and cork-like when dry and has been used for making canoes, rafts and floats for fishing net floats.

How to grow

Soak the seed in water. Sometimes the seeds are parasitised by larvae of beetles and other insects. Soak them overnight and select only those that are sunk to the bottom. The water is very important because it helps to soften the hard seed coat so that germination takes place easier. Other method used to help germination is rubbing or scraping, which involves the use of sandpaper to remove the part of the seed coat. You can also cut and remove a small section of the seed coat with a sharp knife. The black spot on the seed is removed to provide an opening for the water to enter. Pre-emergence fungicide such as Apron is good to help to prevent the seed decay and seed-borne diseases such as dumping-off, root rot and mil- dew on young seedlings. After germination seedlings grow fast and then might contract fungal diseases. This problem of fungal diseases should be then treated with systemic fungicides such as Fongarid. It is a good idea to drench the germination medium with boiling water before sowing. Use a well-drained medium consisting of two parts coarse wash river sand and one part milled pine bark. Seed’s space must about 2-3cm apart and do not cover too deep.

Water well and store in a well ventilated, sheltered area away from direct sunlight. Water seeds daily with fine mist spray. Please do not water late in the afternoon or early evenings because it’s an ideal time for fungus to develop. Sow the seed in October or November.

A second method and the best quickest way of growing a coral tree is to plant the whole branch. Cut branches measuring at least 40mm/diam. The cutting must be made just before the trees come out of dormancy, which is late winter or early spring. After the cuttings allow the wound to dry for 1-2 days, then bury one-third of the branch in the soil, while leaving two thirds to produce the new growth.

Caffra prefers full sun and warm climate and should be planted in sunny places and in well-drained soil. This tree will also put up with dry conditions and poor soils and does respond well to excessively cold conditions.

ecology

According to SANBI staff, both birds and flying insects pollinate coastal coral trees.

The flowers of Erythrina caffra do not produce any fragrance, and only colour, in combination with the reward of nectar, which the tree produces in abundance, is used to attract pollinators. Birds such as red winged starlings, bulbuls, yellow weavers, sunbirds, orioles and many others feed on the nectar and red blossoms and can be seen by the hundreds visiting these trees in the early spring.

The flowers appear before the leaves and this may well be a strategy for visible ad- vertisement to attract as many nectar-feeding birds as possible.

The shape and design of each flower is in such a way that the stamens are exposed and therefore pollen transfer by birds and insects takes place with ease. It is estimated that each flower may hold as many as 7-10 drops of nectar and each flower head may hold up to 80 florets.

The red seeds are also an important food source to many seed-eating birds. Birds therefore not only pollinate the flowers but also aid in seed dispersal, which ultimately impacts on the natural distribution of the species throughout its entire habitat range. The seeds are also eaten by developing larvae of many winged beetles, which lay their small yellow eggs inside the immature pods. Borers also sometimes attack trees and do considerable damage, particularly to young trees. The dead wood of the coral tree is soft and is an ideal nesting place for birds such as the pied barbet (and cardinal woodpecker) while the hollow trunks are often inhabited by swarms of bees.

The branches are armed with prickles, which might serve as protection to herbivores especially when trees are still young. Fully grown trees are fairly drought resistant and can withstand several degrees of frost. In areas where there is severe frost, it may well grow but chances are that they won't flower. See www.plantzafrica.com/plantefg/erythrinacaff.htm

Conservation status

EAccording to the SANBI Red List of South African Plants, caffra has been given an automated status of Least Concern (LC); meaning that it hasn’t been selected for any of the four screening processes to highlight its potential threat status; it is therefore not a species of conservation concern currently, until a full assessment has been conducted. http://redlist.sanbi.org

• Someleze Mgcuwa is a plant digitiser for the Karoo Bio gaps project, based in the Schonland Herbarium