Euphorbia caerulescens four-angled stems

The stems of Euphorbia caerulescens may have as few as four vertical spiny ridges between flat, smooth surfaces as in the photo, resulting in a square appearance in cross-section. In some plants five or six stem ridges bring a star-shape in cross-section, the ridges protruding. Stems are about 5 cm in diameter. The stem colour is usually blue-grey as reflected in the specific name of caerulescens, but green or yellowish green stems are also seen. One of the plant’s common names is blue euphorbia.

Occasional above-ground branching does occur. The stems show intermittent constrictions indicating slow growth periods during adverse climatic conditions.

Tiny, short-lived leaves, only about 2 mm in length, are seen on new growth. Paired spines are spaced up the stems, angling sideways. 

This plant is not too often browsed in the veld, but cattle farmers cut stems, allow them to dry somewhat for use as a palatable drought fodder (Frandsen, 2017; Smith, et al, 2017; Vlok and Schutte-Vlok, 2015; iNaturalist; www.cactus-art.biz).