Chris Mattison / Pencil milkbush (Euphorbia mauritanica) growing among Quiver trees (Aloidendron dichotomum), near Leliesfontein, Namaqualand, South Africa

Chris Mattison / Pencil milkbush (Euphorbia mauritanica) growing among Quiver trees (Aloidendron dichotomum), near Leliesfontein, Namaqualand, South Africa

RHONDA KLEVANSKY / Elephants bush (Euphorbia dregeana) in flower, Richtersveld National Park and World Heritage Site, Northern Cape, South Africa, August.

Gerry Ellis / Milkbush (Euphorbia damarana) in sandstone desert, Huab River Valley, Damaraland, Namibia