[2] The range passes through the countries of Angola, Botswana, Ethiopia, Kenya, Mozambique, Namibia, Somalia, Sudan, Tanzania, Zambia and Zimbabwe.

The genus was originally established by William Jackson Hooker from one species found in South Africa, Pterodiscus speciosus.

[7] The leaves are sub-succulent and fleshy,[8] and very variable in shape,[7] ranging from linear to strap-shaped,[8] undulate to broadly oblong.

[7] They are dentate (toothed), pinnatilobed, pinnatifid (meaning pinnately dissected to the central vein) or pinnatipartite.

[7][8] The corolla is funnel-shaped or narrowly cylindrical, often slightly gibbous (rounded protuberance) at the base with a reduced spur.

[7][8] The fruit (or seed capsule) is indehiscent (does not split down the side),[7][8] instead it has 4 broad longitudinal, prominent wings (which are parchment-like).