Pot: 5,5 cm.
The name of the species comes from the Greek and literally means "with one thorn”. It's a wonderful cactaceae with a very fast growth, which in nature can reach even two meters of height, whilst in pot it keeps much smaller dimensions. Like most species belonging to the genus Opuntia, it has segments that grow on each other and often branch; each of them is formed by flat and ovoid shape, enriched by irregular margin that makes the appearance of the specimen particularly wild. The epidermis is of a lively bright green, on which contrast the sparse areoles and, when present, the single or at the most two spines coming out from each of them, of grey-brownish color, extremely thin and rather long. At the beginning of the summer the charm of this cactus is amply accentuated by gigantic yellow flowers, very lively and showy.