Obregonia denegrii is the only representative of its monospecific genus and is related to Ariocarpus. The stem is solitary, globular-squashed resembling an inverted pine cone with a woolly center, up to 6 inches (15 cm) in diameter and is grayish green to dark green in color. The flowers grow between the wool of the apex, in the center of the stem on young tubercles, they are funnel-shaped white diurnal, up to 1 inch (2.5 cm) in diameter. Fruits are hidden in the wool, pear-shaped, white naked, fleshy and edible.

Growing Conditions

Light: Requires ful sun to develop good compact growth.
Water: Use water sparingly from March till October and keep perfectly dry in winter.
Temperature: It is hardy to 25 °F (-4° C) for a short period.
Soil: Very well drained soil with little organic material (peat, humus).

Propagation

Almost exclusively by seeds. But the seedlings are tiny and very slow growing and at first they take one or two years to reach the diameter of 0.1 – 0.2 inch (3 – 5 mm).

Grower’s Tips

This slow growing cactus isn’t always the easiest species to cultivate, but can enlarge relatively fast when well grown. It is often seen as a grafted plant but grows very well on its own roots too. Needs a very well drained soil with little organic material (peat, humus). Requires full sun to develop good compact growth and watering should be rather infrequent, to keep the plant flat shaped and not become excessively elongated and unnatural in appearance. Use water sparingly from March till October and keep perfectly dry in winter, or when night temperatures remain below 50° F (10° C). It is hardy to 25 °F (-4° C) for a short period. In the rest period no high atmospheric humidity. Ensure a good ventilation.