Barleria

Barleria is a genus of shrublets forming part of the Acanthaceae family. The species growth habits vary much. Some species have spines or thorns growing from leaf axils.

The mostly sessile leaves are opposite (and decussate), simple with entire margins.

The flowers grow solitary, in cymes or thyrses from axils or stem-tips. Bracts and bracteoles are present below the flowers, spiny in some species. The calyx has four lobes that are not identical, from leaf-like to spiny and two usually larger.

The tubular corolla ends from strongly two-lipped to nearly radially symmetrical, either four- or five-lobed. In the two-lipped flowers the upper lip is four-lobed. Flower colours differ widely among white, pink, lilac, purple, scarlet, blue, yellow and orange. The tube is longer than the lobes, widening towards its tip.

There are two or four stamens with long filaments, often twisted and crossing, arising from the central part of the corolla tube. In some species some of the stamens are sterile. The disc is cup-shaped, sometimes with two awns or extended to one side. The ovary has two ovules per locule. The cylindrical style is sometimes branched into two.

The fruit capsule comprises different locules and is beaked in some species. The seeds are flat, hairy discs.

There are about 250 Barleria species worldwide, mainly in the tropics. About 60 of them occur in South Africa. Some, particularly of the spineless species feature in horticulture.

The plant in picture is Barleria obtusa (Leistner, (Ed.), 2000; Vlok and Schutte-Vlok, 2015; Manning, 2009).