Large Plants.

The Astrophytum myriostigma 'Nudum', often affectionately known as the "Bishop's Cap" or "Star Cactus," is a highly prized variant that strips away the typical white flecks to reveal a pure, unadorned green canvas. This extraordinary cactus is a masterclass in sculptural beauty, promising to add a serene, architectural statement and a touch of the stark, refined desert to your collection.

1. Origin of Name

The genus name, Astrophytum, is derived from the Greek words "astron" (meaning "star") and "phyton" (meaning "plant"). This beautifully descriptive name perfectly captures the distinctive star-shaped, often five-ribbed appearance of these cacti when viewed from above. The genus was formally established by Charles Antoine Lemaire in 1839. The specific epithet, myriostigma, is also rooted in Greek, combining "myrios" (meaning "many") and "stigma" (meaning "spot" or "mark"), referring to the dense covering of tiny white flecks (trichomes) that characterize the typical form of the species. However, the special designation 'Nudum' is Latin for "naked" or "bare," and it is precisely this characteristic that defines this prized variant. 'Nudum' varieties lack the white flecks found on other A. myriostigma forms, presenting a smooth, clean, unblemished green surface that highlights its pure form and sharp lines. This deliberate distinction emphasizes its unique, minimalist aesthetic.

2. Origin of Plant

Astrophytum myriostigma is native to the deserts and semi-arid regions of Mexico, primarily found in the states of Coahuila, Nuevo León, San Luis Potosí, and Tamaulipas. It typically grows on rocky hillsides, limestone soils, and open plains, often seeking protection under larger shrubs from the intense desert sun. Its spherical shape and thick epidermis are adaptations to efficiently store water and minimize surface area exposed to evaporation. The 'Nudum' form is a naturally occurring genetic variant found within populations of Astrophytum myriostigma in the wild, though it is often selectively propagated in cultivation due to its high ornamental value and unique appearance. Botanical expeditions into Mexico during the 19th century were crucial in bringing these distinctive "star cacti" to the attention of the scientific world and eager collectors.

3. Description

The Astrophytum myriostigma 'Nudum' is a uniquely structured and wonderfully geometric cactus, highly valued for its striking, unspotted appearance. It typically grows as a solitary, spineless, globular plant when young, gradually becoming more columnar with age, eventually reaching up to 25 cm (10 inches) in height and 10-20 cm (4-8 inches) in diameter. Its body is defined by usually five prominent, deeply separated ribs (though forms with three, four, or up to ten ribs can occur), which give it its characteristic star-like or "Bishop's Cap" shape. The surface of the 'Nudum' form is a pristine, smooth, and often glaucous (bluish-green) green, devoid of the white flecks found on the typical A. myriostigma. This unblemished surface accentuates its architectural form and clean lines. In spring and summer, mature plants produce large, vibrant, funnel-shaped flowers from the apex. These blooms are typically a bright, silky yellow, sometimes with a reddish throat, and can be quite striking against the plain green body, opening during the day and closing at night.

4. Conservation Status

The species Astrophytum myriostigma is generally considered to be of Least Concern on the IUCN Red List of Threatened Species. While relatively widespread, localized populations can be vulnerable to habitat degradation due to agriculture, development, and particularly to illegal collection for the horticultural trade, as it is a highly sought-after species. The 'Nudum' form is a specific variant, and while occurring naturally, its desirability can put pressure on wild populations if not sourced responsibly. Supporting cultivated specimens from reputable nurseries helps to reduce pressure on wild plants and supports the long-term conservation of this unique species.

5. Care

Caring for Astrophytum myriostigma 'Nudum' is straightforward, making it a rewarding plant for both beginners and experienced cactus enthusiasts.

• Watering: As a desert native, it requires sparse watering. Water thoroughly only when the soil is completely dry, typically once every 2-4 weeks during its growing season (spring to early autumn). Reduce watering significantly in winter; a light misting once a month or even no water at all is often sufficient to prevent rot. Overwatering is the quickest way to kill this plant.
• Soil: Absolutely essential is an extremely well-draining, gritty, mineral-based cactus mix. A blend of pumice, perlite, coarse sand, and a small amount of potting soil (e.g., 80-90% inorganic) is ideal.
• Light: Provide full sun to bright indirect light. It thrives in intense light. In very hot climates, some afternoon shade can prevent scorching, but generally, good light is crucial for compact growth and abundant flowering.
• Temperature: Prefers warm temperatures during its active growth period. Protect it from frost, as temperatures below -4°C (25°F) can be damaging. Good air circulation is also beneficial.
• Tips: Ensure adequate ventilation to prevent fungal issues. Avoid overpotting; a pot only slightly larger than the plant is best. Its slow growth rate means it rarely needs repotting. A cool, dry winter rest can encourage more prolific flowering in spring.

6. Engaging Anecdote

The Astrophytum myriostigma, particularly the 'Nudum' form, holds a special place in the hearts of cactus enthusiasts, not just for its beauty but for its common nickname: the "Bishop's Cap." This moniker stems from its distinctive five-ribbed, star-like shape, which bears a striking resemblance to the traditional miter (hat) worn by bishops. This subtle connection imbues the plant with a quiet dignity and an almost sacred aura, making it more than just a succulent – it's a living symbol. The 'Nudum' variant, with its unspotted, smooth epidermis, further refines this elegance, presenting a clean, almost minimalist interpretation of the "Bishop's Cap," highlighting the pure geometry of its form. Its slow, deliberate growth reminds us of patience and the passage of time, making it a meditative presence in any collection. Owning an Astrophytum myriostigma 'Nudum' is not just cultivating a plant; it's inviting a piece of quiet, elegant sculpture into your home, a serene reminder of nature's geometric perfection and its capacity for understated grandeur.