No officially recognized synonyms.

Astrophytum myriostigma cv. Fukuryu nudum is a nursery-origin cultivar, selected by growers and not found in nature. Its parent species, Astrophytum myriostigma, grows on the arid highlands of north-central Mexico, where it inhabits calcareous or gypsum-rich rocky slopes that are highly draining and low in nutrients. These areas are characterized by dry air, infrequent rainfall, and intense sunlight for most of the day, along with marked temperature fluctuations between day and night.

The name Astrophytum comes from the Greek ástron (“star”) and phytón (“plant”), referring to the genus’ characteristic star-shaped cross section. The epithet myriostigma combines myrios (“countless”) and stígma (“dots, spots”), describing the dense covering of white trichomes typical of the species, greatly reduced or absent in the nudum forms, which instead display a smooth, green epidermis. The Japanese term Fukuryu, used among collectors, refers to the presence of additional, irregular ribs.

Astrophytum myriostigma cv. Fukuryu nudum belongs to the genus Astrophytum and to the family Cactaceae. It is a rather rare form associated with the Type B Fukuryu phenotype, characterized by a usually solitary stem and an overall irregular appearance. In addition to the typical five ribs of the species, this cultivar develops extra ribbing and small lateral protrusions, conspicuous and distributed between the main ribs, and lacking areoles. The epidermis, as in all nudum forms, is smooth and glabrous, showing none of the white trichome dusting that normally characterizes Astrophytum myriostigma in nature.

Flowers appear at the apex during the warm season, especially on sunny days. They are identical to those of the species, large and bright yellow. Mature, well-grown plants tend to bloom regularly. After pollination, small rounded fruits form, covered with tiny scales that dry and split open at maturity, releasing numerous shiny black seeds.

This is a slow-growing plant but relatively easy to cultivate.

It prefers a very well-draining substrate that dries quickly after watering. A mostly mineral mix—such as pumice, lava rock, coarse sand, or fine gravel—with minimal organic matter is ideal.

Water sparingly, only when the substrate is completely dry. During summer, watering can be spaced out widely, while in autumn it should be gradually reduced and nearly suspended in winter.

It thrives in very bright locations with several hours of direct sunlight. In summer, a bit of shade during the hottest hours can help protect the smooth nudum epidermis from sunburn. In winter, it can tolerate brief drops down to about 41°F (5°C), as long as it is kept in a cool, dry environment.

A cactus fertilizer low in nitrogen and higher in potassium is sufficient, applied once a month and at low doses. Fertilization should be suspended in autumn and winter.

Repot every 2-3 years, using a slightly larger pot with excellent drainage. Early spring is the best time, allowing the plant to adjust more easily to the fresh substrate.

This plant is not considered toxic to humans or pets and can be grown without any particular precautions.

It is fairly resilient, but it can suffer if the soil remains wet for too long, with a risk of root or basal rot—especially in nudum forms. Among pests, the most common are mealybugs, which often hide in the folds between the ribs, and spider mites in very hot, dry conditions.

This species is propagated almost exclusively from seed, as it normally does not produce offsets. Sowing is done in spring, using a very well-draining and slightly moist substrate, with mild temperatures and bright, diffused light. Seedlings grow slowly, and the Fukuryu traits appear only over time, with noticeable variation among individuals.

The stem color of Astrophytum myriostigma cv. Fukuryu nudum becomes noticeably darker when the plant is grown in light shade.