Astrophytum myriostigma f. cristata
Astrophytum myriostigma f. cristata is a crested (fasciated) form of the bishop's cap cactus, Astrophytum myriostigma, in which the normal single growing point elongates into a line so that the plant builds up as an undulating, fan-shaped ridge rather than a single columnar body. The crest keeps the parent's soft white flecking, so a mature plant reads as a wavy wall of pale, spineless tissue — a much-loved oddity among collectors of the genus Astrophytum.
Crested growth is not a distinct species but a growth mutation (fasciation) that can arise spontaneously in seedlings or on established plants. Because the trait does not come true from seed, crested myriostigma is maintained vegetatively, and choice clones are passed around by cutting and grafting. Care follows the parent species; see Astrophytum myriostigma for the full picture.
Description
Where a normal myriostigma grows as a ribbed, geometric orb or short column, the crested form's growing tip stretches into a continuous line. As that line grows and folds, the plant develops into a brain-like or fan-like mass of contorted ridges. The surface is spineless and dressed in the same fine white woolly flecks (trichomes) that give the species its frosted, marbled look, so a well-grown crest can be strikingly pale and sculptural. The original rib pattern is largely lost in the crested tissue, though it may show near the base or where a section reverts. Plants sometimes throw normal (non-crested) offsets or growing points; these can be removed to keep the crest dominant, or left if you like the contrast. Flowers, when they appear, are the familiar pale yellow of the species, opening along the crest line.
Cultivation
Grow crested bishop's cap essentially as for the parent species: bright light with a little shade from the fiercest afternoon sun, a fast-draining mineral mix (see Soil and potting mix), sparing water with a full dry-out between soakings, and a dry winter rest to keep it hardy and in character (see Watering). Keep it above freezing.
A few points are specific to crests. The dense, convoluted surface traps moisture and shades its own hollows, so good airflow and careful watering matter more than with a plain plant — water into the mix, not over the crest, and let the folds dry quickly. Crests also tend to be greedier for light than their bodies suggest; a little more brightness helps keep the ridge tight and pale rather than soft and stretched. A wide, shallow pot suits the spreading, ground-hugging habit of an older crest.
Many crested and variegated Astrophytum are grown grafted onto a vigorous rootstock, which speeds growth and sidesteps the rot-prone root systems that fasciated plants sometimes have; see Grafting. A crest on its own roots is perfectly possible but slower and less forgiving of overwatering.
See also
- Astrophytum myriostigma — the parent species
- Astrophytum — the genus overview
- Grafting · Soil and potting mix · Watering