Gymnosporia buxifolia, the common spike-thorn, is a spiny shrub or a small tree of up to 9 m (SA Tree List No. 399). The bark on old trees is deeply fissured, corky, dark and rough. Young branches are light brown, later becoming flaky. Moderate or very robust spines are characteristic.
The leaves grow in clusters on small spur-branchlets, sometimes on the green spines themselves. They are narrowly obovate, dull green with the midrib indented above. The margins are finely and irregularly toothed in the upper half only; on the lower half the margin is entire.
The flowers grow in many-flowered heads on spur-branchlets like the leaves. They are almost white, strongly fragrant, appearing mainly in the warmer months. The fruits are more or less spherical, three-lobed, fleshy and greenish-yellow, becoming almost white (Coates Palgrave, 2002).