Obregonia denegrii large specimen:

Obregonia is among the most famous of all cacti for is unique artichoke-shaped stem. It is the only representative of its monospecific genus and is related to Ariocarpus. It grows almost always as a solitary plant levelled with the ground, with a sunk and woolly apex. It is considered an intermediate form between Ariocarpus and Lophophora. This is a very large and old hard-grown specimen.