The stem-tip cyathia of Euphorbia caerulescens grow on the ridges halfway between the old spines here. Euphorbia cyathia or false flowers have evolved in many diverse ways among the many members of this large genus.
Five petal-like glands or bracteoles surround the female flowers, the pistils in the photo, each having a greenish-yellow globular ovary at its base and three conspicuous creamy style branches at the top. Smaller brown male “flowers” can be seen growing in the same clusters with the tall yellow female ones. Male Euphorbia cyathia often consist of just one anther on a filament (Wikipedia).