Origin and Habitat: Argentina (Catamarca Province)

• Gymnocalycium venturianum Backeb.
• Gymnocalycium venturi Frič ex Backeb. & F.M.Knuth

• Gymnocalycium baldianum Speg.
• Echinocactus baldianus Speg.
• Gymnocalycium platense var. baldianum Speg.
• Gymnocalycium baldianum f. cristata hort.
• Gymnocalycium baldianum subs. sanguiniflorum (Werderm.) C.A.L.Bercht
• Echinocactus sanguiniflorus Werderm.
• Gymnocalycium sanguiniflorum (Werderm.) Werderm.
• Gymnocalycium venturianum Backeb.
• Gymnocalycium venturi Frič ex Backeb. & F.M.Knuth

• Gymnocalycium baldianum cv. Yellow

Description: Small usually unbranched,
Stem: Flat to globose depressed, up to 13cm in width, greyish-brown to blue-green (rather variable in colour in cultivation, and in some specimens it is almost blue-black). The 9 to 10 broad ribs are divided by deep grooves into tubercles.
Areoles: deep-set
Spines: 5 to 7 thin radial spines that are straight or curved toward the stem, short, curved, pale brown or grey, tinged with red at the base.
Flowers: on the crown, measuring 3 to 4 cm in length and the same across, open wide in sunlight, and commonly of a most rich purple-red colour, sometimes pinkish-purple (but also white, pink or orange). The stamens are purple, the anthers and the 6 lobed stigma whitish yellow. This plant blooms in early summer when it is only 2.5 cm. It is fast growing and can bloom one year after being sown.
Fruits: The ripened ovary is green, long and dehisces (splits) down its length.
Remarks: The synonym name Gymnocalycium venturianumSN|11974]]SN|11974]] is very common in collections, and even at cactus nurseries. It is a very variable species in its general appearance. There are also many hybrids with a wide range of flower colours.

Notes: It is one of the hybridparent of: Gymnocalycium × pazoutianum Halda Acta Mus. Richnov., Sect. Nat. 5(4): 164 (1998).

Cultivation and Propagation: Very easy to grow, these plants offer no cultivation difficulties. Watering Needs: Moderate to copious in summer, keep dry in winter.
Frost Tolerance: Quite frost resistant if kept dry -10° C (Temperature Zone: USDA 8-10 )

Cultural Practices: Feed with a high potassium fertilizer in summer.
Sun Exposure: Full sun to light shade
Propagation: Seeds (seldom produces offsets)