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Discocactus catingicola

Catinga Disc Cactus

Overview

Discocactus catingicola is a highly sought-after, rare, slow-growing succulent subshrub belonging to the family Cactaceae. Known for its disc-like flattened-globose shape and its distinctive woolly cephalium, this species is prized by collectors but demands meticulous care due to its extreme sensitivity to cold and overwatering.

Taxonomy and naming

This species belongs to the genus Discocactus within the Cactaceae family. The specific epithet catingicola translates to "inhabitant of the Caatinga," referencing the seasonally dry tropical thorn-forest biome of northeastern Brazil where it was discovered 1. Taxonomic synonyms and close relatives include various local forms and subspecies within the broader Discocactus complex 2.

Distribution and habitat

Endemic to Brazil, Discocactus catingicola is native to states including Bahia, Minas Gerais, Goiás, Mato Grosso, and Tocantins 1. It thrives in seasonally dry tropical biomes, primarily growing on sandy flats, quartzitic soils, and rocky outcrops between elevations of 400 and 1000 meters 2.

Appearance

The stem is solitary, globose-depressed, dark green to grayish-green, reaching up to 15 cm in diameter. It features prominent ribs armed with strong, recurved spines that hug the plant body. Upon reaching maturity, it produces a terminal cephalium covered in white wool and dark bristles. From this cephalium, large, nocturnal, highly fragrant white flowers emerge during the warm season.

Cultivation

Cultivating Discocactus catingicola is challenging. It is strictly cold-sensitive and requires a minimum winter temperature of 12°C 3. The growing medium must be highly porous, acidic, and mineral-based. Watering should be thorough but infrequent during the summer, followed by a dry dormancy in winter.

Common cultivation mistakes

Excessive watering during cool periods or winter dormancy is the leading cause of root rot and plant loss 3. Providing inadequate light will lead to etiolation and prevent the formation of the cephalium, which is essential for blooming.

Bibliography

References

  1. Plants of the World Online (POWO), Royal Botanic Gardens, Kew. ↩
  2. Taylor, N.P. & Zappi, D.C. (2004). Cacti of Eastern Brazil. Royal Botanic Gardens, Kew. ↩
  3. Anderson, E.F. (2001). The Cactus Family. Timber Press. ↩
Light

Filtered Sun

Bright, filtered sunlight with protection from intense midday summer sun.

Watering

10-30 Days

Water moderately in summer when dry; keep almost entirely dry in winter.

Soil

Excellently draining, quartz-sand and pumice-heavy, slightly acidic mineral substrate.

Highly porous mineral mix, rich in quartz sand and pumice, low organic matter.

Safety

Pet Friendly

Non-toxic to pets, but possesses sharp, rigid spines that can cause injury.

Difficulty

Hard

Expert level due to extreme sensitivity to cold, moisture, and root disturbance.

Native Habitat

Brazil

Native to the interior arid and semi-arid regions of Brazil, particularly within the sandy, quartz-rich soils of the Caatinga vegetation zones in states like Bahia and Minas Gerais.

Frequently Asked Questions

Can Discocactus catingicola be grown in a pot?
Yes, but it must be grown in shallow, well-draining pots using a highly porous, purely mineral-based soil mix.
What temperature does it need in winter?
This cactus is extremely cold-sensitive. Winter temperatures should never drop below 12°C (54°F), with 15°C (59°F) being ideal.
What is a cephalium and why is it important?
A cephalium is the woolly, bristly structure at the top of mature plants. Flowers only emerge from this structure once it develops.
When does it bloom and is it fragrant?
It blooms during summer nights. The white flowers emit a highly intense, sweet fragrance to attract nocturnal moth pollinators.
Is it toxic to pets?
It is non-toxic to pets. However, its sharp, stiff spines can cause physical injury, so keep it out of reach.
How often should it be watered?
Water only after the substrate has dried out completely during summer. In winter, withhold water entirely to prevent root rot.
What soil mix is best?
Avoid standard peat-heavy soils. Use a mix dominated by quartz sand, pumice, lava grit, and a tiny fraction of acidic organic matter.
What is its growth rate?
It is a very slow-growing cactus. It takes several years from seed to reach maturity and produce its first cephalium.
What happens if the cephalium gets wet?
The woolly cephalium acts like a sponge. If it gets wet, the risk of fungal infections and apical rot increases dramatically.
Why is the stem turning pale or yellow?
It may be receiving too much direct, scorching midday sun, or the roots may have rotted from excess moisture. Check roots and adjust light.