Gymnocalycium gibbosum subsp. borthii (Koop ex H.Till) G.J.Charles

🌱 Morphology
Cactus with a globose-flattened to slightly elongated body, with a grayish-green epidermis that can take on brownish or violet tones. It reaches approximately 9 cm in diameter and up to 10 cm in height. It features 9–16 vertical, low, and rounded ribs, deeply divided into tubercles that give it a characteristic appearance of a succession of small buttons. The areoles, slightly sunken, are initially covered by a fine yellowish-gray tomentum. It usually produces 5–7 radial spines, occasionally up to 9, straight and flexible, with the bottom one generally being longer. It lacks central spines.

🌍 Distribution, habitat, and family
It is endemic to San Luis, Argentina, especially from the two slopes of the Sierra de San Luis, in the vicinity of Quines, where it grows at approximately 600 to 800 m altitude. It is part of the highly variable *Gymnocalycium gibbosum* complex. The former *Gymnocalycium borthii* is currently considered a synonym of this subspecies.
Cactaceae family · Cactoideae subfamily · Cereeae tribe

❄️ Temperature · USDA Zone 9a
It tolerates minimum temperatures of up to −7 ºC for short periods and with the substrate completely dry. Some specialized sources place its potential resistance at around −12 ºC under conditions of absolute dryness, but for safe cultivation in Spain, the more restrictive value of −7 ºC is adopted.

☀️ Lighting
We recommend bright semi-shade, with protection from the most intense sun during the central hours of summer. It tolerates very high light levels, but progressive exposure promotes compact growth and prevents burns. An approximate DLI PAR of 20–30 mol·m⁻²·day⁻¹ is suitable.

💧 Growth cycle and watering
Winter dormancy. During active growth, it is recommended to water abundantly and allow the substrate to dry completely before the next watering. In autumn, the supply is gradually reduced until kept dry during winter. It is a species with relatively rapid summer growth and easy flowering.

🌸 Flowering
The flowers appear laterally, near the apex, and reach approximately 5 cm in diameter. They are white or pinkish-white, with a pink to violet-pink throat and a characteristic pink venation on the tepals. It is an easy-flowering Gymnocalycium.

🌿 Nutrition
During active growth, Desert CHOICE® Cactaceae NPK (Ca-Mg) 4-4-7 (4-4) is recommended once a month along 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 high-tech square pot and with the substrate activated with mycorrhizal fungi and biofungicides.

* As this is an online purchase, the appearance of the specimen sent may vary slightly from the product image. The measurements of the plant are specified in the photo description, but this may also vary slightly, because it is a living being! Each of the Desert CITY plants has unique characteristics.