The thickly succulent Stapeliopsis saxatilis stems are four-angled, square in cross-section. They often grow downwards into the ground before curving up. New branches may begin underground, presenting themselves partly above-ground in various earth-loving postures in the manner of rhizomes. The stems are up to 30 cm long, although often shorter and from 1,3 cm to 2,5 cm wide.
The stem curves in or tapers to its rounded tip. The surfaces on the four stem sides are pale grey-purple and smooth, flat or slightly concave, sometimes covered in random, faintly darker blotches. There are acutely pointed, rigid teeth, broadly triangular and evenly spaced up the stems along the stem angles. The teeth are pale brown and may be slightly down-curved.
There is a tiny bud in the axil of every tooth, capable of growing into a stem branch. It is hairless, green or purplish and eventually grey. Only some of these buds on the lower side of the stem ever grow into branches, maintaining the plant’s burrowing habit (White and Sloane, 1937; Vlok and Schutte-Vlok, 2015; iNaturalist).