Vachellia seyal, the red acacia, known also as the shittah tree (the source of shittim wood), is a thorny, 6–10 m (20–33 ft) high tree with a pale greenish or reddish bark. At the base of the 3–10 cm (1.2–3.9 in) feathery leaves there are two straight, light grey thorns, growing to 7–20 cm (2.8–7.9 in) long. The blossoms are displayed in round, bright yellow clusters approximately in 1.5 cm (0.59 in) diameter.
In Vachellia seyal var. fistula, which is more common on heavy clay soils, some of the thorns are swollen and house symbiotic ants.
It is distributed from Egypt to Kenya and west Senegal. In the Sahara, it often grows in damp valleys. It is also found at wadis in the Arabian Peninsula.