Turbinicarpus jauernigii
| Light | Bright light; a little shade from the harshest afternoon sun |
|---|---|
| Water | Sparingly; let the soil dry fully between waterings, keep bone-dry in winter |
| Soil | Very open, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; give a cool, dry winter rest |
| Propagation | Seed (primary); grafting to speed young plants along |
| Toxicity | Not known to be toxic to cats or dogs |
Turbinicarpus jauernigii is a small, usually solitary cactus of the genus Turbinicarpus, known from a restricted area in Mexico and prized among specialist collectors. It is a modest, slow-growing plant, notable for the neatly spiralled tubercles and short spines of its firm greyish-green body and for its pale, delicately coloured flowers. Some authorities treat it as a subspecies of Turbinicarpus schmiedickeanus (as T. schmiedickeanus subsp. jauernigii).
Description
Turbinicarpus jauernigii forms a small, mostly solitary body, typically globular to shortly cylindrical and only a few centimetres across. The skin is a dull greyish-green, sometimes with a brownish cast, divided into low tubercles arranged in the neat spiralling pattern characteristic of the genus.
Each areole typically bears a single short spine — occasionally a few — that is erect to slightly up-turned and whitish to pale with a darker tip; young plants sometimes also carry several fine radial spines that are lost with age. As with many of its relatives, the spination is somewhat variable from plant to plant.
Flowers open from the woolly crown in the growing season and are pale — soft whitish to gently tinted tones — small and funnel-shaped, opening in bright light over a few days. They are fairly large relative to the modest size of the plant.
Distribution and habitat
The species is known from a very restricted area of San Luis Potosí, Mexico, where it grows on rocky or gravelly ground among sparse vegetation. Like many Turbinicarpus, it tends to grow tucked into crevices and gritty pockets, often contracting into the substrate during drought so that little more than the crown is visible.
Because such narrowly distributed cacti are vulnerable to over-collection and habitat disturbance, the whole genus is listed on CITES Appendix I, giving it a high level of international protection. Nursery-propagated plants are widely and legally available; wild collecting is neither necessary nor lawful.
Cultivation
As with the genus generally, T. jauernigii is undemanding once its need for sharp drainage and a dry winter is respected. Grow it in a very open, mostly mineral mix in a small pot, in bright light with just a little shade from the fiercest afternoon sun. Water thoroughly only when the soil has dried right out during the growing season, then allow it to dry again; keep the plant completely dry and cool through winter to prevent rot and to encourage flowering. See Watering and Repotting for general technique.
The species is naturally slow, so many growers graft seedlings onto a vigorous rootstock to build them up quickly, later growing them on their own roots for a more natural look.
Propagation
Seed is the standard and most reliable method. The fine seed germinates on a warm, mineral surface kept humid, and seedlings are grown on carefully in their first seasons. Because the plant is typically solitary, offsets are seldom available, so vegetative increase is uncommon outside of grafting. See Propagation — seed for a full walkthrough.
Common problems
- Rot — by far the commonest cause of loss, almost always from overwatering, a slow-draining mix, or moisture during the winter rest; the body softens and discolours from the base.
- Etiolation — too little light makes the body swell and pale, and the neat spination loosens and distorts.
- Pests — red spider mites (fine webbing, bronzed skin) and mealybugs (white fluff in the areoles and among the roots) are the usual offenders. See Pests and diseases.
See also
- Turbinicarpus — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · CITES