Euphorbia caerulescens young stem-tip

This plant, Euphorbia caerulescens, previously E. ledienii, shows young stem colour variations the species is capable of. The smooth green parts are yellow-green. Spine colouring starts off pale greenish brown on the stem tops where the young pairs emerge, turning red brown with dark tips as they mature, then grey as they dry on the lower stem parts. Spines on Euphorbia change colour with age almost greying as hair on humans.

The number of stem ribs, ridges or wings normally varies between four and six for the species, here clearly more. The yellow cyathia alternate with the spine pairs in the dips on the stem ridges. The cyathia or false flowers are small and greenish yellow, appearing in winter and spring. The fruits are lobed. 

The wide-angled spine-pairs have rounded bulges in the thick, shared connecting base that lends them the sturdiness for a fierce defence of their flowers and fruits. The spine-tips point down and outwards, not conspicuous on all plants (Euston-Brown and Kruger, 2023; Smith, et al, 2017; Vlok and Schutte-Vlok, 2015; Smith, et al, 1997; www.cactus-art.biz).