Growth Habits: The body of the plant is usually solitary, a darkish green, sometimes almost brown. The plant slowly becomes columnar with age, and up to 4in (10 cm) or more in diameter, with a woolly apex. The ribs are numerous, usually 18 to 20 that bear the areoles. On new growth these are covered with wool and are very distinct, carrying spines up to ½in.. long, but these soon disappear with age. The whole of the plant is covered in a light grey ‘bloom.’ This will rub off if the plant is badly handled or watered from above.
Scientific name: Geohintonia mexicana
Common names: None that I am aware of at this time.
Synonym: None that I am aware of at this time.
Etymology: The genus name Geohintonia remembers its discoverer Georges Hinton. The species name mexicana derives from the state of "Mexico" the land of origin of this plant. (The specific name implies “Mexican”)
Origin: Mexico (Nuevo León: Sierra Madre)
Light: The plant can be placed in full sun, but if the plant is under glass, ensure good ventilation.
Compost: A well drained compost is essential, with a larger than normal mineral content because of the habitat of the plant. It is also suggested that a soil based, rather than for instance a peat based compost is preferable.
Water: Water normally during the growing season, but allow to dry out in winter. If the plant shows signs of distress a little water may be given to stop shrivelling. It is best to try to avoid getting water on the body of the plant. This method will eventually spoil the appearance of the plant.
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Flower: The flowers are deep pink to magenta, growing from the apex of the plant and are approximately 1½in. in diameter.
Fruit: Not known at this time by the author.
Min. temp: 50°f (10°c). It will stand lower temperatures for short periods if the soil is bone dry.
Cultivation: It is not a particularly difficult plant to keep if the above cultural requirements are adhered to, but like all living things it can die for no apparent reason. It is better for the plant if there is a high mineral content in the compost. The plant in habitat grows in what can amount to almost pure gypsum. The grower would be unwise to try to replicate these conditions, but a good open compost is essential to the well being of the plant.
Habitat: This plant grows on gypsum hills on vertical cliffs in the neighbourhood of Rayones. The plant is found close to the locality of Aztekium ritteri. Geohintonia mexicana is now considered endangered in the wild. Virtually the whole of the wild population of the plant has been wiped out by collectors. This has happened in the relatively short space of time since the plant was discovered in 1992.
Comments: There is always a buzz in the cactus hobby when a new plant unlike any other known species is discovered and a new genus is proposed. This cactus is probably the most beautiful of all the ones discovered in recent years. It is only now becoming fairly readily available as a commercially grown plant and can still be quite expensive. It is very slow growing and seedlings may only reach 2 cm. diameter after 8 years of growth.