How to understand GRID refences I use in Haworthia and Gasteria sections? You find them in the section Haworthia (or Gasteria) species - under a concrete species name - the last section "Known localities" in the brackets behind locality name.
To show you an example:
The picture below shows an map with scale 1:250000 - Oudsthoorn 3322.
Example of coordinates "Matjiesvlei (3322BD)":