Xerophyte

Plants of this genus grow low in the soil in their habitat of Northern-Central Mexico. In cultivation, the plants often exhibit a club-shape resulting from the transition between seedling and mature growth. Neither of the two species of this genus are mass-produced in cultivation, but they are much sought after by serious cactus enthusiasts.The species are both tuberculate, but easily distinguished from each other as well as from other cacti. The tubercles are either triangle-shields or ovals topped with strongly pectinate spines. Spines are few on P. strobiliformis, while numerous on P. aselliformis, although, they are hardly recognizable as spines in the later. Flower are dark pink and are borne at the top of the plant, pointing straight up with yellow anthers and stigma. Fruits are small berries with no spines and not dehiscent.