Euphorbia ephedroides is a much-branched succulent shrub reaching heights from 40 cm to 1 m. Smaller plants are more common, in some places found in large stands.
One form of the plant has stiff branches forming a rounded bush (sometimes called var. ephedroides), the other softer with branches tending to be prostrate or suberect, markedly constricted at irregular intervals (sometimes called var. imminuta).
The specific name, ephedroides, indicates resemblance to ephedra, a Greek name for a genus including plants known as horsetails.
The species is found in the north of the Northern Cape in the Richtersveld, southwards into Namaqualand to Steinkopf and eastwards into Bushmanland to Pofadder. Not endemic to south Africa, the species also occurs in southern Namibia.
The habitat is succulent Karoo and Nama Karoo on sandy flats and rocky slopes. The species is not considered to be threatened in its habitat early in the twenty first century (Frandsen, 2017; Williamson 2010; iNaturalist; http://redlist.sanbi.org).