Family Acanthaceae > Subfamily Acanthoideae > Tribe Justicieae.
There are 6 species with 3 from Madagascar and 3 from E. & S. Africa.

They are herbs with a woody base or shrubs.
The opposite leaves have linear cystoliths (calcium carbonate on a cellulose stalk inside a cell).

Inflorescences are long or short cymes with few to many flowers.
(Cymes have the terminal flower on each branch opening first and new flowers can only open below them.)
There are small bracts under the peduncles (inflorescence branches) and bracteoles under the pedicels (flower stalks).

The calyx has a tubular base with 5 long narrow lobes.
The bell-shaped corolla has a short basal tube then a slightly wider throat.
Flowers are bi-labiate or 2-lipped with 2 lobes in the upper lip and 3 in the lower.
The upper lip may have 2 discrete lobes, have 1 lobe with a shallow to deep notch or form a hood.
Two of the 3 lower lobes curve back and the middle one curves down and forwards.

There are 2 stamens and 2 tiny to long staminodes (infertile stamens).
The filaments are inserted onto the throat under the upper lip.
The anthers have 1 pollen sac or theca that may have a short spur at the base.

The superior ovary has 2 locules each with 2 ovules.
The style has 2 short stigma lobes.

The fruit are a club-shaped capsule with seeds only at the swollen end.
Seeds are attached by strong hooked jaculators or retinacula (the hardened ovule stalks).
When the capsule opens the jaculators throw the seeds some distance away.
The smooth flattened seeds have a wide ridge on one side.