Synonyms: Pelecyphora valdeziana, Gymnocactus valdeziana
The name Turbinicarpus comes from the words ‘turbo’ meaning top and ‘karpos’ meaning fruit. This derives from the shape of the fruit produced by some of the plants in this genus (Fig 1).
The genus now has 36 species and now incorporates plants previously described as Gymnocactus and Rapicactus. The most recent discovery is Turbinicarpus graminispinus (Fig 2)
Turbinicarpus valdezianus grows in Saltilo, Coahuila, Mexico. The plants are usually solitary and attain a diameter of 15-25mm growing low to the ground supported by a significant tap root and, as with many Turbincarpus, most of the growth occurring below soil level.
In cultivation the plants usually remain solitary but may also form small clumps over many years. Fig 3 shows an old plant that has been in my collection since 1965. It now has 14 heads still growing happily in a 100mm pot.
All Turbincarpus species require a high mineral, very free draining compost and careful watering, allowing the compost to completely dry out in between. Full sun and hard treatment are essential to maintain the plants’ compact and natural appearance and a winter temperature of 5 – 7degC is ideal.
Turbinicarpus valdezianus is one of the first of the genus to flower, with buds very slowly developing through November and into the winter months (Fig 4) to open usually early-mid March, depending upon the amount of sun. Flowers are usually white with a magenta mid-stripe but a pure white form (albiflora) is also available.
There are many notable species within the genus Turbinicarpus, all relatively easy in cultivation, following the general principles regarding compost, light, temperature and watering. A collection of all the Turbinicarpus species can easily be accommodated in any small greenhouse and will reward with a succession of flowers from early March through to October.