Cacti of the Month (December 2005) Ariocarpus retusus

A more in depth look at individual cactus species, a new one is added each month -managed by Hob
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Cacti of the Month (December 2005) Ariocarpus retusus

Post by templegatejohn »

Ariocarpus retusus Scheidweiler
Ariocarpusretusus.jpg (52.91 KiB) Viewed 1359 times
Growth Habits: The plant is the largest in the genus and also one of the fastest growing. It is almost always solitary, very slowly growing up to 10 inches in diameter (25 cm) The tubercle size and shape can vary enormously and a terminal areole may or may not be present. The plant has a large tap root. The amount of wool at the apex varies from plant to plant.

Scientific name:
Ariocarpus retusus

Common names: Most of the Ariocarpus genus are called Living Rocks.

Synonym: Ariocarpus pulvilligeris, Anhalonium areolosum, Anhalonium elongatum, Ariocarpus confusus, Anhalonium trigonum, Mammillaria prismatica, Anhalonium pulvilligerum, Ariocarpus elongatus, Anhalonium elongatum, Anhalonium prismatic, ,Ariocarpus elongates.

The generic name "Ariocarpus" is derived from the Greek Aria meaning “Sorb” (Sorbus aria – Rosaceae - is the white-beam tree) and the Greek word karpos meaning “fruit.” (The Genus name implies: "fruit similar in appearance to that of the white-beam").

Origin: Mexico (San Luis Potosi, Coahuila, Nuevo Leon)

Light: Will take light shade or full sun.

Compost: Because of the tap root the plant needs to be in very well drained compost with more grit than normal. It also requires a fairly deep pot.

Water: Needs to be watered carefully at all times. This plant can be killed with kindness.

Flower: The flowers 4 to 5cm in diam., 2-4 2cm long; outer perianth parts white, occasionally with reddish midribs, up to 2 cm.long, 5-8mm broad; inner perianth parts white or rarely magenta, to 2cm long, 5-9mm broad; pistil not exerted above the stamens; style up to 2cm. long; stigmas 7-16, 2.5-9mm long.

Fruit: Fruit white, green, or rarely pinkish, 1025mm long, 3-10mm in diam.

Min. temp: Average minimum temperature, 50°f. (10°c). It will stand down to 27°f (-3°c), for short periods.

Cultivation: The plant is sometimes grafted, but it will grow quite happily on its own roots as long as the plant is cared for correctly. It is no good trying to push the plant too hard, trying to acquire a larger plant in a short space of time.

Habitat: It ranges from north of Saltillo, Coahuila southwards to San Luis Potosi, SLP, the easterly limits of the species occur in Tamaulipas, populations are also found in Zacatecas and Nuevo Leon. A retusus ssp. retusus is a plant of the high Chihuahuan desert occurring at altitudes of between 1300 and 2000 metres, on calcareous hillsides and occasionally gypsum plains.

Comments: Not everybody’s cup of tea, but a very nice and unusual plant. For those who like to see their cacti offsetting and flowering profusely, perhaps not the one to buy. For those who have acquired a reasonable collection of cacti and are looking for something a little more unusual and challenging anything from this genus would be ideal. Although it is one of the fastest growing in the genus, it can still take seven or eight years to reach flowering size. This species is one of the easier Ariocarpus to keep fit and healthy.
Photograph by David Angus from