Ariocarpus scaphirostris
| Light | Bright light; a little shade from the fiercest afternoon sun |
|---|---|
| Water | Very sparingly; allow to dry fully, with a long dry rest in winter |
| Soil | Sharply draining, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep well above freezing; roughly USDA zones 9b–11 |
| Propagation | Seed (almost always) |
| Toxicity | Not considered a household toxicity risk, but see Legal status |
Ariocarpus scaphirostris is a rare, slow-growing "living rock" cactus endemic to a small area of Nuevo León, Mexico. It is distinguished from its relatives by narrow, keeled, boat-shaped tubercles — the name scaphirostris means "boat-beaked" — and by its comparatively bright magenta flowers. Like the rest of the genus it is a prized but demanding collector's plant, and one of the more difficult Ariocarpus to establish and grow well.
Description
Ariocarpus scaphirostris forms a low, mostly solitary plant that sits almost flush with the soil, its body largely hidden by a rosette of firm, fleshy tubercles. Unlike the broad, flattened, triangular tubercles of some relatives, those of this species are noticeably narrow, elongated and sharply keeled beneath, curving to a point so that each resembles a small boat or beak. The tubercles are a dull grey-green and lack functional spines, and woolly areole tissue is gathered toward the centre of the plant.
Flowers appear in autumn from the wool at the crown. They are a vivid magenta to purplish-pink, funnel-shaped and relatively large for the size of the body, and are among the brighter blooms in the genus. As with other Ariocarpus, the fleshy tap-rooted body can contract into the ground during drought, leaving little visible at the surface.
Distribution and habitat
The species is endemic to a very restricted area in the Mexican state of Nuevo León, where it grows on rocky limestone slopes among low scrub and grasses. Plants root in gritty, fast-draining substrate and are frequently shaded and camouflaged by surrounding vegetation and stone, making them hard to spot when not in flower.
Because its natural range is so small, the species is highly vulnerable to illegal collection and to habitat disturbance, and wild populations are considered seriously threatened. Nursery-raised, seed-grown plants are the only responsible source; plants should never be taken from habitat.
Cultivation
Ariocarpus scaphirostris has a reputation as one of the trickier members of an already exacting genus, and patience is essential. Grow it in a deep pot to accommodate the tap root, in a very free-draining, mostly mineral mix and in bright light. Water thoroughly only when the medium has dried out completely during the warmer months, then allow it to dry again; keep the plant entirely dry and cool through winter. Overwatering and poorly draining soil are the usual causes of loss, as the fleshy root rots readily if kept damp.
Growth is extremely slow, so avoid the temptation to push the plant with heavy feeding or frequent watering. See Watering and Repotting for general technique, and handle the shallow, brittle root system carefully when repotting.
Propagation
Seed is essentially the only practical method. Fresh seed sown on a warm, mineral surface and kept humid will germinate, though seedlings are slow and need careful, sparing watering to establish. The species does not readily offset, so vegetative propagation is uncommon; some growers graft seedlings onto a vigorous rootstock to speed early growth before returning them to their own roots. See Propagation — seed for a full walkthrough.
Common problems
- Root and body rot — almost always from overwatering or a slow-draining mix; the tap root softens and the plant collapses.
- Loss of the tap root — rough repotting or persistent damp can kill the root; keep the plant dry while it re-establishes.
- Pests — mealybugs (white fluff in the wool and around the roots) and red spider mites are the usual culprits; see Pests and diseases.
Legal status
Ariocarpus scaphirostris is a controlled species. The entire genus Ariocarpus is listed under CITES Appendix I, the strictest category, which tightly restricts international trade in wild-collected plants; artificially propagated, documented specimens may be traded under permit. The species has also been reported to contain trace alkaloids, in common with several other Ariocarpus.
This article is a horticultural reference only. It provides no information on consumption, preparation or extraction of any kind. Growers should be aware of the plant's protected status and comply with CITES rules and any applicable national and local laws when acquiring or trading specimens.
See also
- Ariocarpus — the genus overview
- CITES · Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting · Pests and diseases