Euphorbia rhombifolia on the gravel plains of the Tanqua Karoo under a sky with cloud formations signalling an approaching cold front, Western Cape, South Africa. [photo Colin Paterson-Jones ©]

Euphorbia rhombifolia flowering in late spring in the Tanqua Karoo, Northern Cape, South Africa. [photo Colin Paterson-Jones ©]

Pelargonium magenteum flowering freely in spring on a dolerite boulder between plants of Euphorbia rhombifolia in the northern Tanqua Karoo, Northern Cape, South Africa. [photo Colin Paterson-Jones ©]

The climber, Cyphia digitata, twined on a shrub of Euphorbia rhombifolia, both flowering in spring in the northern Tanqua Karoo Northern Cape, South Africa. [photo Colin Paterson-Jones ©]