Euphorbia mammillaris branching at a stem-tip

This young branched tip of a Euphorbia mammillaris stem has been very busy. It produced yellow cyathia, some of which have already reddened with age or turned brown. There are fleshy green nectar glands in a ring of discs around each cyathium and bracts below those. The cyathia emerge from the seams between the tubercles, the leaves from the tubercle centres to slightly higher up.

The compact rosette of tiny, inner, stem-tip leaves is dull green with creamy yellow margins in picture. Their fleshy blades angle out with smooth margins and pointed tips. The outer, red leaves are soon more widely spaced as the tubercles on which they grow singly expand. By the time the leaves reach the sides of the stem in its elongation, new tubercles having succeeded the older ones in the centre on the top, the time of the ephemeral leaves is up. They take their leave, leaving only whitish tubercle tip scars when they fall.

The angular bulges of the stem surface sections, the tubercles, form a neat stem pattern resembling roof tiles. The pattern is retained lower down as the stem-tip moves further up. The old spines are short, thick and whitish when dry, tapering to menacing hard tips (Euston-Brown and Kruger, 2023; Frandsen, 2017; Smith, et al, 2017; Vlok and Schutte-Vlok, 2010; iNaturalist; Wikipedia).