Monsonia spinosa long stalked leaves

When the Monsonia spinosa leaf blades drop off their long stalks, what remains becomes hard and sharp enough in spine mode to do damage to intruder flesh.

The spines serve as a deterrent in defence of the plant. Living things live off other living things, therefore tend to develop defences for ensuring survival of the species. Defences take a great many forms in nature.

Pale grey once they dry out, these spines brought the species its name of spinosa.

The contrast between long and short-stalked leaves on the stem is visible in the photo (Le Roux, et al, 2005; iNaturalist).