Mammillaria crinita
| Light | Bright light with a few hours of direct sun; some shade from the fiercest afternoon sun |
|---|---|
| Water | Moderately in the growing season, letting the mix dry fully between waterings; keep dry and cool in winter |
| Soil | Fast-draining, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; roughly USDA zones 9b–11 |
| Propagation | Seed and offsets |
| Toxicity | Non-toxic to cats and dogs |
Mammillaria crinita is a small, clustering cactus from central Mexico and one of the most variable members of the huge genus Mammillaria. Rather than a single tidy species, it is best understood as a complex — a swarm of closely related, intergrading forms that has swept up dozens of once-separate names. Plants are typically globe- to short-cylinder-shaped, freely offsetting into clumps, and armed with slender radial spines and one or more hooked central spines, above which appear rings of small cream to yellowish (sometimes pinkish) flowers. Its bewildering variability is exactly what makes it a favourite among collectors.
Description
Mammillaria crinita forms small, soft-bodied stems that are usually solitary when young but soon branch and cluster, building low mounds over time. Individual heads are generally a few centimetres across, globose to shortly columnar, and covered in conical tubercles arranged in the neat spirals typical of the genus. Between the tubercles the axils may carry a little wool or a few fine bristles.
Spination is the source of much of the complex's variability. Each areole bears a spreading ring of fine, pale radial spines, and one to several stouter central spines — at least one of which is characteristically hooked at the tip, often darker and reddish-brown to amber. Small, funnel-shaped flowers appear in a ring near the crown in spring and summer, ranging through cream, greenish-yellow and pale pink depending on the form. Pollinated flowers are followed by slender red or pinkish berries holding tiny seeds.
Distribution and habitat
The complex is widespread across the highlands of central Mexico, growing in a range of situations from rocky slopes and cliff crevices to gravelly flats and scrubby grassland. Across this broad range the plants vary enormously in body size, spine colour, hook strength and flower colour, which is a large part of why so many local forms were historically described as distinct species. Like all cacti, the genus is listed under CITES Appendix II, so wild collection and cross-border trade are regulated; nursery-raised plants are common and freely traded.
Cultivation
Mammillaria crinita is an accommodating, beginner-friendly cactus, asking little more than sharp drainage and plenty of light. Grow it in a very free-draining, mostly mineral mix and give it bright conditions with a few hours of direct sun to keep the body compact and the spines strong. Too little light causes soft, etiolated growth and stingy flowering.
Water moderately through the warm months, always letting the mix dry out completely before watering again, and then keep the plant dry and cool over winter — this winter rest both prevents rot and encourages the spring flush of flowers. The soft, clustering bodies dislike sitting wet, so err on the dry side. See Watering and Repotting for general technique, and lift and divide crowded clumps every few years.
Propagation
The complex is easily increased both ways. Seed is straightforward: sown on a warm, gritty surface and kept humid, it germinates readily, and because the group is so variable, seed-raised batches often show pleasing variation. Established clumps also give up offsets that can be teased away, allowed to callus, and rooted in a barely-moist mineral mix. See Propagation — seed and Propagation — offsets for full walkthroughs.
Taxonomy
Mammillaria crinita is a textbook example of a "species complex". Many plants once described under their own names — including forms circulated in the hobby under labels such as Mammillaria wildii and Mammillaria painteri — are now widely treated as part of this variable assemblage. Because the boundaries between forms are blurry and authorities disagree, collectors will encounter the same or similar plants under a range of older names. When buying, it is worth treating the label as a guide to appearance rather than a firm identification.
Common problems
- Rot — the usual killer, brought on by a slow-draining mix, overwatering, or watering during the cold, dark months; affected heads soften and discolour from the base.
- Etiolation — too little light produces pale, elongated growth and loss of the compact, tightly-spined habit.
- Pests — mealybugs (white fluff among the tubercles and in the roots) and red spider mites (fine webbing and bronzed skin) are the common offenders; see Pests and diseases.
See also
- Mammillaria — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — offsets · Pests and diseases