Vachellia flava (Forssk.) Kyal. & Boatwr.
Mimosa flava Forssk., Acacia flava (Forssk.) Schweinf., A. ehrenbergiana Hayne, A. seyal auct., non Delile
Eng.: Desert acacia. Spa.: Acacia. Fre.: Acacia. Ara.: Hardha, salam, seram, tamaya (sing.) tamate (plural). Tamahaq: Tamat, tamāt, temat.
Spiny shrub up to 4 m in height, highly branched from the base —shaped in V—, or a tree up to 6(7) m in height, hermaphrodite, deciduous, very ramose. Trunk and main branches with bark brown-greenish or dark brown, smooth, with many lenticels, that peels into papery laminas —then yellow-green—, ± glabrous. Young branches puberulent, brown or greenish. Stipular spines (2)4-6(7) cm —longer than the leaves—, paired, divergent, straight, white, hairy at the base. Leaves 3-5(8) cm, alternate, bipinnate, glabrous or puberulent, with petiole 0.5-1.5 cm, with 1 gland and ± hairy, and rachis with 1-2(4) pairs of pinnae —with 1 gland at the insertion of the upper pinnae—, each with (5)8-12 pairs of leaflets 2-4 × 0.75-1(1.5) mm, oblong or narrowly obovate, rounded at the tip, subsessile, entire, ciliate, dull light green in colour. Inflorescences in spherical capitula, 10-15 mm in diameter, with numerous minute flowers, bright yellow, axillary, solitary or in fascicles of 2-5, peduncle long 1-3 cm, longer than the leaves. Calyx 1-1.5 mm, glabrous except for the puberulous teeth. Corolla c.
2.5 mm. Stamens very numerous. Pod (3)4-10(12) cm × 4.5 mm, pendulous, linear, straight or curved —in spiral when mature—, compressed, ± constrained between the seeds, glabrous, red at first turning brownish, dehiscent, 6 -8 seeds. Seed (3.5)4-6.5 × 2-3 mm, ovoid, compressed, brown-blackish, smooth.
Flowering:
January to March N of the Sahara, in summer in tropical areas S of the Sahara, just after the rainy season.
Fruiting:
February to April or August to October.
Habitat:
Semidesert and desert areas, on sandy or stony soils, in depressions and watercourses, in areas with 50-400 mm of annual precipitation.
Distribution:
North Africa (Sahara and Sahel), Arabian Peninsula and Iran. In North Africa, it is less common than V. tortilis but also widely distributed, from the coasts of the Atlantic to the coasts of the Red Sea. It is present in the Sinai Peninsula but it seems to be missing from Tunisia.
Observations:
Together with V. tortilis, it is one of the most ecologically valuable species in the Sahara, due to its importance as protector of soils, humidity and biodiversity. It is also of significant direct value to humans as it produces gum and resins, used as gum Arabic and in traditional medicine for its anti-inflammatory and diuretic properties. Unfortunately, like other Saharan and pre-Saharan tree species, it is disappearing and it has barely regenerated, not so much due to climate change, but as a direct result of human actions. Trees are cut and/or uprooted, or they are slowly but progressively eliminated over decades because their roots and bark have numerous medicinal properties. Its wood is also used for coal and as fuel. Its spiny branches are cut to build fences. However, the main cause of the decline of the species is overgrazing, which prevents regeneration.
Conservation status:
A relatively common and widespread species, but becoming every day scarcer in spite of its economic and ecological value. In the IUCN Red List of Threatened Species, it is listed as Least Concern (LC) at global level (Contu, 2012). In Mali it is included in its List of species that need authorization for commercial use (Decree 07-155/P-RM of 2007).