Origin and Habitat: Argentina (La Rioja)

• Gymnocalycium ubelmannianum Rausch

Description: Plants are usually solitary, or form clusters with age. Stems are flattened, globose, often pulling into the ground, glaucous grey-green, up to 1 cm high and 7 cm in diameter. With 8-12 ribs, forming distinct tubercles with chin-like protrusions and grooves between the areoles.
Spines: Spine clusters have a characteristic spider-like shape, Spines (all radials): 5-7, chalky white, flexible, somewhat curved and often twisted, one pointing downward, 0.5-1.5 cm long.
Flowers: Cream-white, sometime with a darker pinkish-red throat, up to 3.5 cm in length and in diameter.
Fruits: broadly globose, green, up to 6 mm in diameter.
Remarks: The length of the spines is quite variable, even in seedlings of the same batch - from 5 to 20 mm.

Cultivation and Propagation: It is a summer-growing species that offers no cultivation difficulty. Water regularly in summer (but do not over-water). Keep rather dry in winter. Feed with a high potassium fertilizer in summer. It is quite frost resistant if kept dry (hardy to -5° C). Sun Exposure: Light shade.
Propagation: Direct sow after last frost. (seldom produces offsets).