Frailea pumila f. rubrispina is a morphological form of Frailea pumila distinguished from the latter by the red coloured young spines. The differences with other Frailea pumila are in reality very minimal and the two plants are not readily distinguishable, if not for the colour of the new spines. It has a well-developed contractile tuberous root system. These tuberose roots have the function of storing enough sustenance so that plants can survive the periods of drought that they have to endure. Tuberous roots also have the function of anchoring the plants into the ground.