Pot: 6,5 cm.
The crested shape of this cactus has a very particular fan crest as it will never be found identical in two or more different plants; making each one unique and for this reason highly sought after by collectors around the world. In its normal form, it is a cactus with a tuberculate globose stem and with large fluffy white areolas. The name comes from the Greek and means "ash", in reference to its usual color tending to greyish, but probably also for the spontaneous growth of several species on the ashes of volcanoes. During the flowering period, in spring, its beautiful flowers bloom in colors ranging from white to yellowish.