Euphorbia heptagona stems curving up

The stems and branches of this Euphorbia heptagona, in Afrikaans klipnoors (stone spurge), are erect, angled or curve up with straight or rounded vertical ridges, scalloped instead of angular in cross-section. Stem colour is a dull pale green here, the surfaces covered in a powdery coating. Some plants may display angular stem ridges and the coating or bloom not always present. 

Previously called E. atrispina var. atrispina, one of the swartdoringnoorse of the Oudtshoorn to Ladismith region, the young spines are black in this form, as the common name suggests. The other discarded variety, var. viridis, suggests greenness at least in parts (Euston-Brown and Kruger, 2023; Smith, et al, 2017; Vlok and Schutte-Vlok, 2015; Smith, et al, 1997; JSTOR; iNaturalist; iSpot).