A plant (the pink flower) in its natural habitat in Mina, Nuevo Leon, among dried mud
(Photo by: Marco Antonio Arroyo, Mexico)

Ariocarpus kotschoubeyanus is a wonderful specie with beautiful looks but extremely slow growing on its own roots. All its forms and varieties are worthy of cultivation and sought after by collectors.

It is very flat and does in most cases not reach more then only a few centimetres above the ground. Although they can form clumps, often only a small disc of tubercles can be seen flat at the soil surface, however these plants grow a large tap root below the surface of the compost.
 

A. kotschoubeyanus var. albiflorus (Tula Tamaulipas, Mexico)


A. kotschoubeyanus (var. elephantidens)


A. kotschoubeyanus (form Rioverde)

 

Description: They are geophyte plants that produce small star-shaped rosettes. They are usually solitary, rarely giving rise to side shoots from old areoles, flattened on top, depressed centrally. The tubercles are deltoid dark olive green  with no spines and lie flat on the soil surface. They are more long than wide, closely packed and divergent, sharply angled apically;    Areoles forms a central longitudinal areolar groove extending to the tips on the adaxial surfaces of the tubercles, woolly, 1-3 mm wide, 5-10 mm long.  Each plant has a large turnip-like taproot, which lies below the soil surface and serves for water storage. These plants have a  woolly  crown, from which emerge bright pink-violet flowers up to 2.5-5 cm, 2 times wider than long when fully expanded. Flowers arte diurnal and last for 3 to 4 days. Blooming time from mid-September onwards. Fruits white or green with lots of seed. The white-flowered variety was described as var. albiflorus.

A. kotschoubeyanus is a variable species:

As with most other widely distributed species of this genus there appears to be geographical clines, in this case a north - south cline and a west - east cline.
The plants in northern populations (known as A. kotschoubeyanus. var. macdowellii) are smaller than the type, with small beak-like tubercles and pale mauve flowers, often with a high white content in the outer petals.
In contrast the southerly form ( known as A. kotschoubeyanus var. elephantendens) are much larger with larger, highly textured, triangulate tubercles, and a deep purple flower with little or no white content.
A. kotschoubeyanus ssp. sladkovskyi differs from the other red flowering A. kotschoubeyanus (that have a dull and rough epidermis) for having a smoother and shiny epidermis.
A small growing form with white flowers (known as A. kotschoubeyanus var. albiflorus) has been described in Tamaulipas.
The type species is intermediate between all the above forms and is to be found off highway 80, between El Huisache Junction and Santo Domingo.
 

Cultivation  The plants need deep pots to accommodate the napiform unit formed by the stem base and the rootstock , and a loose mineral soil with a well-drained substrate. They need a good amount of light, a place near the roof of the greenhouse helps drying the pot after watering. This can be done weekly during summertime, if the weather is sunny enough, with a little fertilizer added. Kept this way, plants will show a healthy, although slow growth. They are frost hardy to -10°C
Propagation: By seeds, remembering that  seedlings dislike strong light and dry conditions  and need to be repotted frequently. Eventually, as they become mature, they attain a maximum size of 5 to 9 cm. But plants are often grafted to accelerate growth as they would generally take at least a decade to reach maturity on their own, but the grafted plants are typical rather tall growing, compared with plants on their own roots that are usually very flat to the ground.

Conservation status: Listed in CITES appendix I

Original Publication: Anhalonium kotschoubeyanum Lemaire, (1842) [Bas.] Bull. Cercle. Confer. Hort. Dep. Seine.

Synonyms:

• Ariocarpus sulcatus Schumann K. (1894) in Engler & Prantl, Nat. Pflanzenfam. 3, 6a:195

• Roseocactus kotschoubeyanus (Lemaire) A. Berger

Origin: Mexico, This species is widely distributed as a large number of small, isolated populations in a big area extending over 600 km, from central Coahuila in the north to Queretaro in the south, and the species is also found in the states of Zacatecas, San Luis Potosi, Nuevo Leon and Tamaulipas.
 

Habitat and Ecology:  Commonly called "living rocks," they are widely distributed as a large number of small, isolated populations, generally on limestone derived gypsum silt plains and on hills, at elevations of around 1000-1400 metres, The area where they grow must be quite wet during the rainy season (Summer). This plants are extremely cryptic and  are very difficult to spot as they blend in well with the terrain around them resembling dried mud. When they are found, it is usually due to their pinkish flowers. In times of severe drought the whole above-ground portion of these plants can shrink and be covered by mould, but the taproot remains alive.

The crown of the plants flush with the muddy It is quite possible (indeed inevitable) that they get walked on which doesn't seem to harm them at all!

(Photo by: Marco Antonio Arroyo, Mexico)

Another  mud dweller Lophophora williamsii

Photo of conspecific taxa, varieties, forms and cultivars of Lobivia (Echinopsis) pentlandii .
 of plants belonging to the Lobivia... complex (This Taxon has lots of synonyms (like most Lobivia) whit several controversial varieties and subspecies):

• Ariocarpus kotschoubeyanus
• Ariocarpus kotschoubeyanus forma mostruosa
• Ariocarpus kotschoubeyanus forma prolifera
• Ariocarpus kotschoubeyanus var. albiflorus
• Ariocarpus kotschoubeyanus var. elephantidens
• Ariocarpus kotschoubeyanus var. macdowellii
• Ariocarpus kotschoubeyanus var. sladovski