Astrophytum myriostigma 'Kikko'
Astrophytum myriostigma 'Kikko' is a curious mutant cultivar of the bishop's cap cactus, Astrophytum myriostigma, in which the normally smooth, continuous ribs break up into stacked, horizontally divided tubercles that resemble the overlapping plates of a turtle's shell — the trait that gives it the Japanese name kikko ("tortoiseshell"). It is prized by collectors for its strange, sculptural, almost carved-from-stone appearance.
The Kikko mutation has been selected and stabilised chiefly by Japanese Astrophytum enthusiasts, where it has long been a hobby favourite. It is not a single fixed clone but rather a heritable growth pattern that can be expressed to varying degrees, so plants range from lightly segmented to dramatically knobbly. Because A. myriostigma is naturally spineless, Kikko keeps that clean, spine-free look while adding heavily tuberculate texture.
Description
Where a typical bishop's cap forms clean vertical ribs, a Kikko plant has each rib interrupted by horizontal grooves, so the body appears built from tiers of rounded, wedge-shaped bumps stacked one above another — the tortoiseshell effect. The number of ribs (commonly around five, but variable) is inherited from the parent, and the flecking of tiny white woolly scales (myriostigma meaning "countless spots") is usually retained, giving the segmented tubercles a soft grey-green, felted appearance. Flowers, when they come, are the familiar Astrophytum yellow, sometimes with a red-orange throat, opening from the woolly crown. The mutation is often combined with other A. myriostigma variants; a Kikko carrying the near-spotless, smooth-skinned nudum trait is sometimes distinguished as Kikko-hekiran, showing bare green tubercles rather than white-flecked ones.
Cultivation
Care is essentially the same as for the parent species, Astrophytum myriostigma. Give it bright light with a little protection from the most intense afternoon sun, a fast-draining mineral-rich mix (see Soil and potting mix), and water sparingly, letting the pot dry out fully between drinks and keeping it dry and cool through winter dormancy (see Watering). Keep it above freezing.
One point worth noting: the deep grooves and stacked tubercles trap water, dust and debris far more readily than a smooth ribbed plant. Water at the roots rather than over the body, and take extra care that moisture does not sit in the crevices, especially in cool or humid conditions, as this is where rot most often takes hold. Generous airflow and a truly gritty, free-draining substrate go a long way.
Propagation
Kikko is most reliably propagated by Grafting onto a vigorous stock, which pushes fast, plump growth and is the usual way nurseries bulk up choice mutant forms. It can also be raised from seed (see Propagation — seed), though the tortoiseshell trait segregates and only a proportion of seedlings will show it strongly — part of the fun for hobbyists selecting their own plants. Offsets are rarely produced.
Common problems
- Rot — the greatest risk, driven by water pooling in the deep tubercle grooves. Water the soil, not the crown, and ensure fast drainage and good airflow.
- Etiolation — too little light causes stretching that blurs the crisp, stacked tortoiseshell segments; give bright light to keep the form tight.
- Pests — mealybugs love to hide in the shaded crevices between tubercles; inspect regularly, as they are easy to overlook on such a textured plant.
See also
- Astrophytum myriostigma — the parent species
- Astrophytum — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed