Family Acanthaceae > Subfamily Acanthoideae > Tribe Justicieae.
There are 59 or 60 species from tropical areas of Australia, Africa, Asia, and New Guinea.

They are shrubs or herbs with opposite leaves.
Leaves almost always have a smooth edge and rarely a toothed one.

Terminal or axillary inflorescences are a spike or a raceme.
Racemes have solitary flowers, on a pedicel along a midrib with the lower ones opening first.
Spikes are like a raceme except the flowers have no, or almost no pedicel.
There are large or small bracts, and bracteoles that are typically very small.

The calyx has a short tubular base and 5 lobes with one longer than the others.
The corolla has a tubular base and a longer funnel-shaped throat with 5 lobes.
The lobes may be slightly or markedly in 2 lips with 2 in the upper and 3 in the lower.
In either case the middle petal in the lower lip is slightly larger and typically has a wrinkled area.

The 4 stamens, usually of two different lengths are inserted onto the base of the throat.
The anthers, with 2 pollen sacs or thecae usually lie within the throat.
The base of the sacs have 1 (2 or 3) spur.

The superior ovary has 2 locules each with 2 ovules.
The style may have some hairs at the base.
It has 2 stigma lobes that may be of different sizes.

The fruit are a club-shaped capsule with up to 4 seeds in the swolllen end.
Capsules open explosively and the seeds are ejected by their jaculator or retinaculum.

The flattened roughly circular seeds have a nodular or wrinkled surface.
They may have an irregularly lobed edge.