Vachellia seyal (Delile) P.J.H. Hurter
Acacia seyal Delile.
Eng.: Red acacia, white galled acacia. Spa.: Acacia. Fre.: Mimosa épineux, seyal. Ara.: Soffa, elalk, seyal, sayyal, hankich, thalhaïe (Choua), sedra ebéda (Hassanía). Tam./Tamahaq: Tefi, talakh, thala, tamat, tarmat, talh, turreuft, hurfé, uref, uref, oroff, orffan.
Tree or shrub up to 12 m in height, spiny, hermaphrodite, deciduous, with a thick trunk and crown umbrella-shaped in adult specimens. Trunk and main branches with bark thin, smooth, greyish-green, that peels into rectangular strips exposing a greenish yellowish or reddish-orange farinaceous layer. Young branches smooth, pale yellowish to greyish, glabrous but with small reddish-brown green glands. Stipular spines, to 6(8) cm —shorter than the leaves—, paired, divergent, straight, narrow, white or grey. Leaves 4-8 cm, alternate, pinnate, with petiole up to 1 cm, and rachis with 3-6(8) pairs of pinnae —with 1 gland at the insertion of the upper pinnae—, each with (8)10-20(25) pairs of leaflets 3-6 × 0.75-1.5 mm, oblong, rounded at the apex, subsessile, glabrous or ciliate on the margins, a dark green. Inflorescences in spherical capitula, 10-15 mm in diameter, axillary, solitary or in fascicles of 2-3(5), pedunculate —peduncle up to 3.5 cm—, with numerous minute flowers, bright yellow. Calyx c. 2 mm, with puberulous teeth. Corolla 3.5-4 mm. Stamens numerous. Pod 7-22 cm × 3-10 mm, linear, pendulous, curved, ± constricted between the seeds, chestnut in colour, glabrous, dehiscent with 6-10 seeds. Seeds 6-9 × 4-5 mm, ellipsoid to obovate, compressed, yellowish-brown, smooth.
Flowering:
Before the leaves appear, right at the end of the dry season (February to March).
Fruiting:
3-4 months after Flowering.
Habitat:
Diverse terrains in desert and subdesert environments, usually in depressions and valley bottoms where the edaphic moisture is higher. It can survive in temporarily flooded land (the word “seyal” comes from Arabic, meaning “stream”, referring to its association with water). It often forms thickets, sometimes impenetrable. In the wettest areas of tropical Africa (above 400 mm per year) it can grow away from watercourses.
Distribution:
Southern Sahara, Sahel, the driest parts of eastern Africa (from Egypt to Mozambique) and the Arabian Peninsula. In North Africa, it reaches towards the N to the S of the Anti-Atlas (Morocco), the Ahaggar Massif (Alegria) and the S of Egypt (Aswan, Qena).
Observations:
In eastern Africa (S of the 10 parallel, from Somalia to Zambia, and Mozambique) var. fistula (Schweinf.) Kyal. & Boatwr. (Acacia fistula Schweinf. A. stenocarpa Hochst. ex A.Rich.) is represented, characterised by the base of the spines, swollen and adnate, that are used by ants as nests.Its resin is marketed in Sudan under the name of “Talh”.
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 Algeria it is included in the List of protected non cultivated flora (Executive Decree 12-03 on 4-Jan-2012). In Mali it is included in its List of species that need authorization for commercial use (Decree 07-155/P-RM of 2007).