Spines, Thorns, and Prickles | The Huntington

To a botanist, however, not all spiny structures are the same… Spines are derived from leaf tissue and thorns from stem tissue. Prickles come from neither; they are simply corky projections from a plant’s skin, or dermal tissue. Plant anatomy comes into play here, as the internal structure of leaves, stems, and roots are unique in their arrangement.

About the photo - a different source

Solanum atropurpureum is a wild relative of potatoes that grows in Brazil. It has prickles so nasty that they’ve earned it two fearsome nicknames: “purple devil” and “malevolence.”