This cactus is native to the highlands of central and northern Mexico, growing at 750-1500 metres above sea level. It needs stony, calcareous or lime soils, so it is usually found on on scrubby alluvial plains on steep and slopes, or on foothills of mountain ranges. Agave lecheguilla acts as a nurse plant to A. myriostigma.
This cactus grows usually solitary, or with very few basal branches. The stem is globular to cylindric, and it has a bright green epidermis with a chalck-white look, due to the little hairy scales that cover it. It has a star shaped section, giving the plant a bisghop’s mitre appearance. Ribs are regular, prominent and acute; usually they are five and can increase to eight or more, aging. Glossy-yellow, funnelform flowers bloom on the tip of the stem, reaching up to 7cm lenght.
This Astrophytum is a relatively easy-to-grow species. It needs a mineral, well-draining soil, with little humus. Water sparingly from March till October, letting the soil getting dry before watering again. To avoid root rot, keep it dry from the beginning of autumn to the end of winter. It is theorically hardy to -5°C, but during cold months keep it in a cool place. It does well from full sun to light shade: with a good amount of light, plant’s colours will get brighter and richer.
Propagation is almost enterily done by seeds.
The name of the genus Astrophytum derives from the Greek words “astèr” which means “star” and “phytòn” which means “plant”, as these particular cacti have many ribs, which, seen from above, look just like stars.
Beacause of its peculiar shape, A.myriostigma is commonly called Bishop’s cap. Many varieties and breeds of A.myriostigma are available nowadays.