Astrophytum myriostigma var. nudum
Astrophytum myriostigma nudum is native to the state of San Luis Potosì (Mexico).
Astrophytum myriostigma var. nudum distinguishes from other myriostigma for its smooth epidermis: it lacks completely or mostly the characteristic white flecks of myriostigma. As a results, its stem, which can be spherical or shortly columnar, shows its colours: bright green, blue-green, gray-green or mauve-green. It can get up to 120 cm tall, and its section is star-shaped. Ribs are usually 5, but can be from 3 to 8. After 6 years of life, A. myriostigma nudum can bloom from spring to early summer, forming pale-yellow, silk-shining flowers.
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; you can also add a little fertilizer. To avoid root rot and frost damages, keep it dry from the beginning of autumn to the end of winter. It is theoretically hardy to -7°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, the plant will get beautiful and healthy.
Propagation is usually, easily done by seeds; anyway, this Astrophytum is sometimes grafted on other cacti.
This cultivar lacks the white flecks on its stem and its epidermis is smooth: from that, the name “nudum”.