The genus and species combination commemorates two Mexican politicians: Alvaro Obregon and Señor Denegri, President and Minister of Agriculture, respectively, at the time the plants were discovered in 1923 by Alfred Frec. The genus is comprised of a single species which is unique in appearance with respect to that of other cactus species, and, therefore instantly recognizable. Stems are solitary, as well as flattened and globose and have triangular tubercles, which are arranged in a spiral and give the plant an appearance similar to an artichoke. Areoles are small at the apex of the tubercles and weakly defended by 3 or 4 small spines. Flowers are funnel-shaped, white with yellow stamens and come from the top-centre of the plant. Several authors have studied the relationship existing between Obregonia and other cactus genera, such as Ariocarpus and Strombocactus, but DNA sequencing confirmed it is only related to Lophophora. Not difficult to grow, if you have a little patience.