The stem of Euphorbia sekukuniensis is marked by vertical bands and scars from old spine shields on the whitish, leafless surface. The spines that had once grown there have dropped off long ago. While young lateral stems are angled with flat sides, the old trunk gradually loses the flat surfaces, becoming cylindrical.
Branched, curved stems, up to 2 cm in diameter, form a rounded crown at the stem top; green above where the branchlets are live, pale grey below where they have become desiccated, but not yet dropped off. In this way the small crown on the sturdy, lengthening stem appears continually more out of proportion as the tree ages.
This photo was taken at the De Hoop Dam in Sekhukhuneland, Limpopo, during September (Frandsen, 2017; Smith, et al, 2017; Coates Palgrave, 2002; iNaturalist; Wikipedia).