Euphorbia louwii

Euphorbia louwii, commonly in Afrikaans Wynand-se-noors (Wynand's spurge), is a spiny stem succulent reaching heights around 1 m. It may branch much at the base, less so higher up.

The slender, erect stems have five to seven vertical and intermittent dark ridges or ribs, although the stems may sometimes be nearly cylindrical. Young stems are usually green, the bluish hue appearing later. The stem bases on older plants lose their colour, becoming rough and corky with whitish bark. The narrow spine shields with paired spines on the stem ribs are not continuous but conspicuous. A smaller, single spine is positioned below each shield. 

The small, yellow or yellowish green inflorescences consist of three horizontally arranged cyathia. These closely spaced false flower clusters may almost cover upper stem parts in season. The involucre is funnel-shaped and the peduncle on each cyathium short.

The species distribution is very restricted to a small area in the Waterberg around Marken near Mokopane in Limpopo.

Although the plant is rare, it is not deemed threatened early in the twenty first century, as its habitat of rocky patches in open woodland remains little affected by prevailing farming activities (Smith, et al, 2017; iNaturalist; www.plantzafrica.com; http://redlist.sanbi.org).