Senegalia polyacantha

Senegalia polyacantha, commonly the white thorn or white-stem thorn, is an erect, deciduous tree growing a spreading to flat crown up to 20 m in height (SA Tree List No. 180). The yellowish bark peels in corky flakes, exposing whitish underbark, giving rise to the common name. Hooked thorns grow in pairs below each stem node on younger stems.

The bipinnate leaves are spirally arranged on the stems, from 13 to 40 pairs of pinnae on the rachis that becomes up to 20 cm long. The leaf petiole becomes 0,5 cm to 4 cm long, with a gland somewhere upon it. Every pinna bears 26 to 66 pairs of narrow to narrowly triangular leaflets. There are glands on the rachis at the base of the upper pair of pinnae.

The flowers appear with the spring leaves in elongated, white to yellowish spikes, up to 12 cm long and may be seen up to early summer. The brown, hairless pod is leathery, straight and flat, tapering at both ends. It becomes up to 18 cm long and 2,1 cm wide and is dehiscent.

In South Africa the white thorn only occurs in an easterly part of Limpopo, being widespread beyond the border in several tropical African countries. Its habitat is bushveld, usually on alluvial soils near rivers. The species is not considered to be threatened early in the twenty first century.

African S. polyacantha trees all belong to subsp. campylacantha; the typical subspecies being Asian, found in India (Coates Palgrave, 2002; Van Wyk and Van Wyk, 1997).