This is one of the rarest and highly desirable of the living rock cactus, very characteristic and unmistakable. Somewhat similar to Ariocarpus, it resembles an inverted green pine cone with a woolly centre.
 

Two individuals showing the variable morphology of this species. The first (more typical) with broad large spaced tubercles and the second with densely packaged tubercles and numerous long yellow spines.

A young specime (5 years old)

Blooms

Scientific Name: Obregonia denegrii Fric

Synonym:

• Ariocarpus denegrii,
• Strombocactus denegrii
   

Vernacular name: Artichoke cactus

Conservation status: Listed in CITES appendix I

Origin: Mexico (Tamaulipas: Ciudad Victoria)

Habitat: Obregonia denegrii thrives among small stone in association with Agave lechuguilla, Ariocarpus trigonus, and Astrophtum myriostigma, in an area where erosion is a serious problem.   Sometimes plant are washed out of the ground by rain.

( Photo and © Copyright by Marco Antonio Arroyo - Mexico )
Photo in habitat

Cultivation: Obregonias are propagated by seeds. Seedlings are sometimes grafted to increase their growth speed. This slow growing plant isn't always the easiest species to cultivate, but can enlarge relatively fast when well grown. Light sun.