(Gymnocalycium oenanthemum)

Gymnocalycium oenanthemum is a species of flowering plant in the family Cactaceae, endemic to Argentina. A slightly flattened sphere growing to 12 cm (4.7 in), it has 10-13 ribs, each containing a row of tubercles with radial spines. In summer it bears a wine-red or pink daisy-like flower. In cultivation in the UK and other temperate regions it cannot survive freezing, so at least in the winter months it must be kept indoors in a bright, cool environment with minimal watering. It has gained the Royal Horticultural Society’s Award of Garden Merit. Gymnocalycium, commonly called chin cactus, is a genus of about 70 South American species of cactus. The genus name Gymnocalycium (from Greek, "naked calyx") refers to the flower buds bearing no hair or spines. Their main area of distribution is Argentina, part of Uruguay, Paraguay, southern Bolivia and part of Brazil. Most species are rather small varying from 4 to 15 centimetres in size. In cultivation they are popular for their easy flowering habits, and the flowers are generally brightly coloured. Where temperatures fall below 10 °C (50 °F) they must be cultivated under glass with heat.
