Ceratonia siliqua L.
Eng.: Carob tree, locust bean. Spa.: Algarrobo, garrofera. Fre.: Caroubier. Ara.: Kharruba, kharruba, kharrub, slaghua, slirua, abemid. Tam.: Tikerrubl, tasligua, asriuia, sclarua, tikidat, tsitt, ikidu; the green fruit: abernid; the ripe fruit: tikida; the seed: tirbilt.
Tree up to 10 m in height, monoecious —rarely polygamous or hermaphrodite—, evergreen, with well defined trunk, short, thick, tortuous, with grey-brown or grey and smooth bark, rounded crown. Branches thick, extended, greyish, younger branches hairy. Leaves alternate paripinnate, with 2-4 pairs of leaflets of 2-5.5 × 1.6-4.2 cm, petiolulate, obovate to elliptic, with rounded or emarginate apex, sometimes apiculate and ± rounded base, coriaceous, dark green on the upper side and slightly lighter on the underside, hairy at first —as well as the rachis— and the whole leaf turning glabrous. Inflorescences racemiform, born directly on the branches and even on the trunk, male, female or hermaphrodite. Perianth monochlamydeous, cup-shaped, very small, with 5 triangular lobes, greenish or reddish, sericeous. Male flowers usually with 5 stamens, free, with greenish filament and anther yellow or reddish. Female flowers with sericeous pistil, ending in disc-shaped stigma, ± bilobed. Pod 8-25 × 2-3 cm —in wild specimens usually they do not exceed 15 × 2 cm—, compressed, linear-elliptical and often slightly curved, glabrescent or with applied scattered hairs, green at first, then red-brown and finally blackish and coriaceous, with 1-17 seeds. Seeds 8-10 × 6-7.5 mm lenticular, slightly compressed, brownish, smooth.
Flowering:
September to January.
Fruiting:
One year later.
Habitat:
Forests and thickets on various types of soil, though preferring calcareous soils. In semiarid to subhumid bioclimate, on inframediterranean and thermomediterranean floors. It does not withstand frosts.
Distribution:
Mediterranean region. In North Africa it is common in the lowlands of most of the Mediterranean region, from Morocco to Egypt and the Sinai Peninsula. It does not penetrate far inland, since it does not withstand the continental climate. However under favourable conditions it can reach the Saharan Atlas, reaching up to 1,600 m above sea level.
Observations:
Cultivated for its beans, it is a common tree in the Mediterranean area, and in some Saharan oases. It used to form dense forests throughout the territory, especially in Algeria and Tunisia, but now they have disappeared due to modern agricultural practices. These forests, of which some examples can still be seen in marabouts or Muslim cemeteries, are mainly composed of thermophilic trees and shrubs, such as Olea europaea, Phillyrea latifolia, Tetraclinis articulata, Rhamnus lycioides and Pistacia lentiscus. The fruits of the carob tree have several uses, often being used as human and livestock food, since their fleshy pods are highly nutritious, with up to 40% sugar. The seeds have a very uniform weight and therefore they have long been used for weighing drugs, precious stones and metals, etc. and continue to be used today. The Greek name of the carob tree and seed, keration, became the Arabic names karat and quirat, that gave origin to the word carat (or karat), the unit that is currently used to determine the purity of precious metals, such as gold, and also the unit that measures the mass of precious stones such as gems and pearls. From the seeds, locust bean gum can be obtained, which is used in pharmaceutical, cosmetic, textile and other industries.
Conservation status:
A relatively common and widespread species, not considered threatened. In the IUCN Red List of Threatened Species, it is listed as Least Concern (LC) at global level. In the Red List of vascular plants of Egypt (Flora Aegyptiaca Vol 1, 2000) it is listed as “Endangered”.