Publication: Acta Mus. Richnov., Sect. Nat. 5(5): 185. 1998
Description
Ariocarpus kotschoubeyanus subs. albiflorus is a dwarf cactus with unique and remarkably beautiful shape. It is a small growing form of the variable Ariocarpus kotschoubeyanus and is distinguished for the white or pale pink flowers.
Habit: They are very flat geophyte cactus that produce small star-shaped rosettes. They in most cases don’t reach more than 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.
Stem: Usually solitary, rarely giving rise to side shoots from old areoles, flattened on top, depressed centrally.
Tubercles: 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: The tubercles 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.
Roots: Each plant has a large turnip-like taproot, which lies below the soil surface and serves for water storage.
Flowers: These plants have a woolly crown, from which emerge white or very pale pink (never magenta-violet), 2,5-5 cm, 2 times wider than long when fully expanded.
Blooming time: Mid-September onwards. Flowers are diurnal and last for 3 to 4 days.
Fruits: White or green with lots of seed.
Origin and Habitat
Around Tula, Tamaulipas, Mexico.
Altitude: It grows at elevations of around 1200-2000 metres.
Habitat: Commonly called “living rocks,” they are edaphic specialist plants that generally grows on limestone derived gypsum silt plains and on hills. The area where they grow must be quite wet during the rainy season (Summer).
Ecology: 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 white 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 main threats to this species are human settlements, illegal collecting, and local medicinal uses. Some localities have been partly depleted by illegal collectors.
Cultivation and Propagation
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 cm.
Bibliography
Major references and further lectures
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James Cullen, Sabina G. Knees, H. Suzanne Cubey “The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass” Cambridge University Press, 11/Aug./2011
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David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
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Edward F. Anderson “The Cactus Family” Timber Press, 2001
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Nathaniel Lord Britton, Joseph Nelson Rose “Cactaceae: Descriptions and Illustrations of Plants of the Cactus Family” Volume 3, 1922
Gómez-Hinostrosa, C., Sotomayor, M., Hernández, H.M. & Smith, M. 2013. Ariocarpus kotschoubeyanus. In: IUCN 2013. “IUCN Red List of Threatened Species.” Version 2013.2. <www.iucnredlist.org>. Downloaded on 18 February 2014.
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