🌱 Morphology
Small, slow-growing Gymnocalycium, generally solitary, with a globose-flattened body, with dark green, grey-green, or green epidermis with intense brown-purple hues. It can reach approximately 6–12 cm in diameter. It has 9–14 ribs that are relatively narrow, tall, and well-defined, with lighter transverse bands that create the characteristic geometric pattern of this origin. The areoles are small, whitish, and pubescent. In the LB 2178 clone, the colouring becomes more intense with bright light and contrasting temperatures.

🌍 Distribution, habitat, and family
The taxon originates from the Chaco of Paraguay and eastern Bolivia. The material marketed as ‘Agua Dulce’ LB 2178 comes specifically from Agua Dulce, Alto Paraguay, Paraguay, where Ludwig Bercht collected it in 2000. This is a low-altitude area, approximately between 10 and 500 m, with a warm, seasonal climate, Chaco vegetation, and clay soils. LB 2178 is a field number and not a cultivated variety.
Cactaceae family · Cactoideae subfamily · Cereeae tribe ·

❄️ Temperature · USDA zone 9b
Tolerates minimum temperatures of up to −4 ºC for short periods and with completely dry substrate. As it comes from a warm, low-altitude environment, it should be protected especially from the combination of cold and moisture.

☀️ Lighting
It needs plenty of light to maintain the contrasting bands and the green, purple, and brown hues of the epidermis. Soft direct sunlight or very bright partial shade is recommended, avoiding sudden exposure to the intense midday summer sun. PAR radiation of 20–30 mol·m⁻²·day⁻¹ (DLI) promotes compact colouring and good flowering.

💧 Growth cycle and watering
Winter dormancy. Growth is concentrated during the warm months. During the active period, it is recommended to water abundantly and let the substrate dry out completely before the next watering. In autumn, watering is gradually reduced until it is kept dry during the winter.

🌸 Flowering
It produces large flowers in relation to its small body, white in colour, sometimes with pink or brown hues towards the outside, measuring up to about 5 cm, which may open incompletely. Flowering occurs mainly from mid-summer to autumn. Adult plants may produce several flowers during the favourable season.

🌿 Nutrition
During active growth, Desert CHOICE® Cactaceae NPK (Ca-Mg) 4-4-7 (4-4) is recommended once a month with watering. Assimilable calcium promotes the formation of firm tissues and the maintenance of turgidity, while magnesium participates in chlorophyll synthesis. Before flowering, it can be supplemented with Desert CHOICE® Flowering.

🪴 Pot
9x9 cm gourmet black pot

This is an inimitable xerophyte grown in Madrid in a technological square pot with substrate activated with mycorrhizal fungi and biofungicides.