Mammillaria dioica (fish hook cactus) (viejitos)

It has unusual reproductive morphology as suggested by its species name. Populations having normal bisexual flowers, while other individuals display only female flowers. It is distributed along the western margin of the Sonoran Desert east of the Peninsular ranges and then in coastal sage scrub and maritime succulent scrub along the coast of southern California from Del Mar south into northwestern Baja California-where it is often abundant. Of the three species of fish hook cactus, this is the only one that can form multi-stemmed clumps, although solitary stems are also found."California Desert Plants, Philip W Rundel, Robert J Gustafson, Micahel E Kauffmann."