T he Astrophytum myriostigma Fukuryu Hakujo Type B is a highly unusual collector’s cactus valued for its intricate rib structure, smooth green body, and distinctive surface texture. It is a cultivated form of Astrophytum myriostigma. Unlike the typical species, this nudum form has little or none of the characteristic white flecking, allowing its green epidermis and unusual sculptural growth to stand out.
The Fukuryu Type B form is particularly distinctive because it develops irregular wart-like structures between and across the ribs, while Haku-Jo characteristics can add woolly lines connecting the areoles along the ribs.
This cactus is popular among collectors because it combines several unusual characteristics in one plant. The Fukuryu Type B form is considerably rarer and more irregular than Type A, with prominent surface growth that gives the body a highly textured appearance. The nudum characteristic means the plant has very few or no white flecks, while Haku-Jo refers to the woolly connections between the areoles.
The plant has a rounded to slightly columnar, spineless body with prominent ribs, but its exact appearance can vary considerably as it develops.
Type B is distinguished by numerous irregular raised structures or “warts” between and on the ribs, while the nudum form has a mostly green surface rather than the dense white flecking seen on typical A. myriostigma.
Haku-Jo forms are recognized by woolly lines that visually connect neighboring areoles. The cactus remains slow-growing and usually solitary, although older plants can gradually become taller and more cylindrical.
The flowers come from the growing point near the top of the cacti and are one of the most attractive features of mature Astrophytum myriostigma.
They are generally yellow to creamy yellow, sometimes showing orange or reddish tones toward the center, and can reach several centimeters across. Flowering usually occurs during the warmer growing season once the plant reaches maturity, and Astrophytum flowers are known to attract bees and other flower visitors.
When growing indoors, use a well-drained cactus mix for optimal growth. Water thoroughly only after the soil has dried completely, then allow excess water to drain away; constant moisture around the roots is one of the main risks for this cactus. Place it in the brightest available location, ideally beside a south- or west-facing window where it can receive several hours of direct sunlight, while acclimating it gradually to intense sun. Keep it warm during active growth, generally around 65–85°F, and provide good air circulation. Humidity should remain low to moderate, and there is no need to mist the plant.
Outdoors, this cultivar should be grown in a warm, frost-free climate similar to the conditions preferred by its parent species.
Place it around USDA Zones 9–11, although protection from prolonged cold and wet conditions is still important.
Give it bright light to full sun, preferably with gradual acclimation if it has previously been grown indoors.
During spring, feed lightly with a diluted, low-nitrogen NPK fertilizer; heavy feeding can produce softer growth and detract from the compact form.
Fertilizing should be reduced or stopped during the cool dormant period. Pruning is normally unnecessary because the plant naturally maintains its sculptural form; simply remove damaged or diseased material when needed.
The Bottom Line
Overall, the Astrophytum myriostigma HakuJo (Type B) is an exceptionally distinctive collector cactus with a green nudum body, unusual Type B wart-like structures, and characteristic Haku-Jo woolly connections between its areoles. Its slow growth, sculptural appearance, yellow flowers, and rarity make it particularly attractive for specialist cactus collections. Give your plant bright direct light, very fast drainage, completely dry periods between waterings, low humidity, light feeding, and protection from prolonged cold and wet conditions for the best growth.
Bloom Season
Flower Color
Growth Rate
Hardiness Zone
Mature Size
Plant Type
Resistance
Sun Exposure
Watering Needs
| Attribute | Value |
|---|---|
| Bloom Season | Summer |
| Botanical Name | Astrophytum myriostigma Fukuryu |
| Common Name | Bishop's cap cactus |
| Dormancy | Winter |
| Family | Cactaceae |
| Flower Color | Yellow |
| Genus | Astrophytum |
| Growth Habit | Globular |
| Growth Rate | Slow |
| Hardiness Zone | 9, 10, 11 |
| Mature Size | 12 in. tall, 6 in. wide |
| Native Area | Japan |
| Plant Type | Cactus |
| Propagation | By seeds, stem cuttings |
| Resistance | Extremely drought-tolerant, heat resistant, pest resistance, disease resistant |
| Soil PH | 6.5, Acidic, Neutral |
| Soil Type | specialized cactus potting soil |
| Special Features | Easy to grow |
| Sun Exposure | Full sun (6+ hrs.), Partial shade (3–6 hrs. sun) |
| Toxicity | Mild toxic for humans, mild toxic for pets |
| Watering Needs | Low |
Growers Quick Reference Guide - Key Features
| Attribute | Value |
|---|---|
| Bloom Season | Summer |
| Botanical Name | Astrophytum myriostigma Fukuryu |
| Common Name | Bishop's cap cactus |
| Dormancy | Winter |
| Family | Cactaceae |
| Flower Color | Yellow |
| Genus | Astrophytum |
| Growth Habit | Globular |
| Growth Rate | Slow |
| Hardiness Zone | 9, 10, 11 |
| Mature Size | 12 in. tall, 6 in. wide |
| Native Area | Japan |
| Plant Type | Cactus |
| Propagation | By seeds, stem cuttings |
| Resistance | Extremely drought-tolerant, heat resistant, pest resistance, disease resistant |
| Soil PH | 6.5, Acidic, Neutral |
| Soil Type | specialized cactus potting soil |
| Special Features | Easy to grow |
| Sun Exposure | Full sun (6+ hrs.), Partial shade (3–6 hrs. sun) |
| Toxicity | Mild toxic for humans, mild toxic for pets |
| Watering Needs | Low |
- Description
- Key Plant Features
T he Astrophytum myriostigma Fukuryu Hakujo Type B is a highly unusual collector’s cactus valued for its intricate rib structure, smooth green body, and distinctive surface texture. It is a cultivated form of Astrophytum myriostigma. Unlike the typical species, this nudum form has little or none of the characteristic white flecking, allowing its green epidermis and unusual sculptural growth to stand out.
The Fukuryu Type B form is particularly distinctive because it develops irregular wart-like structures between and across the ribs, while Haku-Jo characteristics can add woolly lines connecting the areoles along the ribs.
This cactus is popular among collectors because it combines several unusual characteristics in one plant. The Fukuryu Type B form is considerably rarer and more irregular than Type A, with prominent surface growth that gives the body a highly textured appearance. The nudum characteristic means the plant has very few or no white flecks, while Haku-Jo refers to the woolly connections between the areoles.
The plant has a rounded to slightly columnar, spineless body with prominent ribs, but its exact appearance can vary considerably as it develops.
Type B is distinguished by numerous irregular raised structures or “warts” between and on the ribs, while the nudum form has a mostly green surface rather than the dense white flecking seen on typical A. myriostigma.
Haku-Jo forms are recognized by woolly lines that visually connect neighboring areoles. The cactus remains slow-growing and usually solitary, although older plants can gradually become taller and more cylindrical.
The flowers come from the growing point near the top of the cacti and are one of the most attractive features of mature Astrophytum myriostigma.
They are generally yellow to creamy yellow, sometimes showing orange or reddish tones toward the center, and can reach several centimeters across. Flowering usually occurs during the warmer growing season once the plant reaches maturity, and Astrophytum flowers are known to attract bees and other flower visitors.
When growing indoors, use a well-drained cactus mix for optimal growth. Water thoroughly only after the soil has dried completely, then allow excess water to drain away; constant moisture around the roots is one of the main risks for this cactus. Place it in the brightest available location, ideally beside a south- or west-facing window where it can receive several hours of direct sunlight, while acclimating it gradually to intense sun. Keep it warm during active growth, generally around 65–85°F, and provide good air circulation. Humidity should remain low to moderate, and there is no need to mist the plant.
Outdoors, this cultivar should be grown in a warm, frost-free climate similar to the conditions preferred by its parent species.
Place it around USDA Zones 9–11, although protection from prolonged cold and wet conditions is still important.
Give it bright light to full sun, preferably with gradual acclimation if it has previously been grown indoors.
During spring, feed lightly with a diluted, low-nitrogen NPK fertilizer; heavy feeding can produce softer growth and detract from the compact form.
Fertilizing should be reduced or stopped during the cool dormant period. Pruning is normally unnecessary because the plant naturally maintains its sculptural form; simply remove damaged or diseased material when needed.
The Bottom Line
Overall, the Astrophytum myriostigma HakuJo (Type B) is an exceptionally distinctive collector cactus with a green nudum body, unusual Type B wart-like structures, and characteristic Haku-Jo woolly connections between its areoles. Its slow growth, sculptural appearance, yellow flowers, and rarity make it particularly attractive for specialist cactus collections. Give your plant bright direct light, very fast drainage, completely dry periods between waterings, low humidity, light feeding, and protection from prolonged cold and wet conditions for the best growth.
Bloom Season
Flower Color
Growth Rate
Hardiness Zone
Mature Size
Plant Type
Resistance
Sun Exposure
Watering Needs
| Attribute | Value |
|---|---|
| Bloom Season | Summer |
| Botanical Name | Astrophytum myriostigma Fukuryu |
| Common Name | Bishop's cap cactus |
| Dormancy | Winter |
| Family | Cactaceae |
| Flower Color | Yellow |
| Genus | Astrophytum |
| Growth Habit | Globular |
| Growth Rate | Slow |
| Hardiness Zone | 9, 10, 11 |
| Mature Size | 12 in. tall, 6 in. wide |
| Native Area | Japan |
| Plant Type | Cactus |
| Propagation | By seeds, stem cuttings |
| Resistance | Extremely drought-tolerant, heat resistant, pest resistance, disease resistant |
| Soil PH | 6.5, Acidic, Neutral |
| Soil Type | specialized cactus potting soil |
| Special Features | Easy to grow |
| Sun Exposure | Full sun (6+ hrs.), Partial shade (3–6 hrs. sun) |
| Toxicity | Mild toxic for humans, mild toxic for pets |
| Watering Needs | Low |
Growers Quick Reference Guide - Key Features
| Attribute | Value |
|---|---|
| Bloom Season | Summer |
| Botanical Name | Astrophytum myriostigma Fukuryu |
| Common Name | Bishop's cap cactus |
| Dormancy | Winter |
| Family | Cactaceae |
| Flower Color | Yellow |
| Genus | Astrophytum |
| Growth Habit | Globular |
| Growth Rate | Slow |
| Hardiness Zone | 9, 10, 11 |
| Mature Size | 12 in. tall, 6 in. wide |
| Native Area | Japan |
| Plant Type | Cactus |
| Propagation | By seeds, stem cuttings |
| Resistance | Extremely drought-tolerant, heat resistant, pest resistance, disease resistant |
| Soil PH | 6.5, Acidic, Neutral |
| Soil Type | specialized cactus potting soil |
| Special Features | Easy to grow |
| Sun Exposure | Full sun (6+ hrs.), Partial shade (3–6 hrs. sun) |
| Toxicity | Mild toxic for humans, mild toxic for pets |
| Watering Needs | Low |
