Say it: jim-noh-kuh-LISS-ee-um. Common names: chin cactus. The name means “naked calyx” — the flower buds are smooth, with no spines or wool.
Where it grows
Across southern South America: Argentina, Bolivia, Paraguay, Uruguay and southern Brazil, often in grassland and among rocks at altitude. G. bruchii, G. baldianum, G. curvispinum and G. altagraciense are all Argentine.
Size and growth
Small, flattened globes with rounded ribs that bulge into “chins” below each areole. Most stay under 4 inches across; bruchii forms clusters of inch-wide heads. Moderate growth, and quick to flower — often 2–3 years from seed.
Flowers
Funnel-shaped flowers from the crown through spring and summer: pink in bruchii, deep red (or white in the form we grow) in baldianum, white to pale pink in most others. They repeat for months and are big for the plant.
Care
- Light: bright light with some protection from harsh afternoon sun. Many Gymnocalycium redden or scorch in full desert sun.
- Water: regular in warm weather, dry and cool in winter.
- Soil: gritty with some organic matter.
- Cold: bruchii is one of the hardier cacti, to around 15–20°F if dry; the others are safer above freezing.
From seed
Easy. Germination in 7–21 days. A good genus for windowsill growers, since the plants stay small and flower young.
G. bruchii pavlovskyi seeds · G. baldianum seeds · G. curvispinum seeds · G. altagraciense seeds · G. bruchii plant