Living Rocks of Mexico
The Aramberri Enigma
  home  [ species ] [ A. retusus ] [ A. trigonus ]  


Distribution (Map)

Populations of this variant of the Ariocarpus retusus complex exist in several locations around Aramberri, Nuevo Leon,  populations to the north of Aramberri tend to be predominantly white flowered, with occasional bicolored or pink flowers, those to the west are virtually all deep pink flowered. 

Arioocappus Aramberrii

Ariocarpus sp. Aramberri, classical form of the plant with deep pink flowers



Plants of the Ariocarpus retusus/trigonus complex in the Aramberri region are extremely diverse in body form, and also in flower color. Morphologically the plants can vary from the appearance of typical A. retusus to typical A. trigonus, with a range of intermediates between the two. The most interesting variation is in the flower color, which can range from white through to deep pink, a color not found in any other populations of A. retusus/trigonus. Bicolored flowers also occur. The exact status of these plants is not fully understood. A separate species, A. confusus, was erected by Halda & Horacek in 1998 for the Aramberri plants, but given the extreme variability of the population this would appear premature.

Anderson & Fitz Maurice in the 1997 review of Ariocarpus (Haseltonia 5) hypothesized that the population is the result of hybridization between the two sub-species of A. retusus, the meeting of the two being facilitated by the canyon which runs through the Sierra in this area, this theory whilst accounting for the morphological variation does not explain the pink flowered plants. Cultivated hybrids between the two have so far failed to produce other than the expected whit e/cream colored flowers as illustrated here.  An alternative theory on the origins of these plants proposed by the author of this piece (J. Miller) is that the population may represent an ancestral form of both A. retusus and A. trigonus, migration to the east having resulted in A. trigonus, whilst migration into the higher ground to the west has resulted in A. retusus.


Ariocarpus Aramberrii

Ariocarpus sp. Aramberri, form with bicolored flowers

Ariocarpus .retusus x triigonus

 An artificial hybrid of A. retusus x A. trigonus with characteristics intermediate between the two


Flower color in Ariocarpus species, with the exception of A. retusus/trigonus is pink with an occasional white variant. a factor which is taken as further evidence of the more primitive nature of the pink flowered plants, white/yellow flowers would appear to be derivative of pink. If the ancestral form theory is correct it gives further support to the unification of A. retusus and A. trigonus as one species, by providing a common ancestor for both forms. It may, of course, be that these plants represent no more than an extremely genetically diverse population of A. retusus. Much more study will be needed before the taxonomic problems posed by the Aramberri populations are fully resolved.

Field Numbers

A full listing of all associated field data can be found on our field number reference pages, some associated numbers include:.SB1426,  LH470, LH471, PP 416, PP420, PP421, PP581, PP585, PP957

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