Euphorbia perangusta in marching formation

The Euphorbia perangusta stems are formed up erectly in a clump here, like a platoon of foot soldiers adapted to the constraints imposed by the surrounding rocks. Much of the branching must be taking place below-ground in plants like this.

Spaced sections of taller stem ridges and bigger spines characterise the stems. These periodic bursts of super-growth may be associated with rainy seasons, like year rings in trees. The effect of the possible constrictions in quiet times of reduced progress lends the stems resemblance to E. cooperi although not the tree-like, single trunk habit.

Porcupines sometimes eat parts of E. perangusta plants (Frandsen, 2017).