It produces yellow or orange flowers in autumn, that open at night, and have the aroma of cloves.

The ball shape is formed from the plant's leaf-pair having fused entirely, leaving only a tiny slit at the top, where the flower and the succeeding leaf pair pushes through.

calculus is restricted to the "Knersvlakte" region, in the far north-west of the Western Cape Province, South Africa.

The subspecies vanzylii occurs over 100 km to the north, in the western part of Bushmanland.

Therefore, in spite of the semi-arid climate and desiccating sun, the soil is typically quite cool (due to the reflective white of the quartz pebble-fields).