Pot: 10 cm.
Its name N. ottonis honors the German botanist Christoph Friedrich Otto. This is a dwarf cactus, that can be both solitary and grouped. Its stem has a more or less spherical shape, with a slight cavity at the apex. The epidermis takes on different shades of intense green, which tends to become purplish during the winter rest. The brown spines are sparse, thin and long. It is a plant easy to grow, that blooms in summer with beautiful yellow blooms. N. ottonis is perfect for decorating any windowsill.