Pot: 5,5 cm.
Cactaceae with a very particular look, formed by a globose stem in which emerge immediately prominent, sharp and turned upwards tubercles, of a beautiful very intense light green. Each stem does not reach remarkable size, but tends to light up with great facility, obtaining ample tufts of heads strongly shaggy due to the long white-yellowish and thin radial spines. They are arranged radially at the apex of each tubercle, contrasting with the single, even longer, brown central thorns, which turn outwards. In the complex, the plant is therefore strongly spiny and wild, with the spines crossing each other giving it that intertwined look that has earned the nickname of "bird’s nest". Only in spring M. decipiens "softens" showing wonderful white-pink funnel-shaped flowers.