Achyrocalyx

Achyrocalyx is a genus of flowering plants in the family Acanthaceae. It is native to Madagascar.
Taxonomy.
It was first described by Raymond Benoist in 1930 (in a publication dated to 1929). 
Description.
They are said to be shrub-like and are found at elevations of .
Species.
The African Plant Database recognises the following four species as of 2012: