Parodia ottonis (Notocactus ottonis)

Clumping globose cactus. More or less globose stems, 2-15 cm in diameter, dark green in colour, with 6-12 well-defined ribs. On the ribs there are numerous areoles from which several yellow-brown thorns develop, tending towards the stem. Apical flowers 3-6 cm in diameter, yellow with purple stigma. Flowering occurs in spring. Native species of the subtropical prairies of South America: southern Brazil, Uruguay, north-eastern Argentina and southern Paraguay. It grows both in the grass and between stones or on rocks. It requires well-drained soil but with a small percentage of humus and a position in full sun (especially in winter) or partial shade (especially in summer). Water every 10-15 days from March to April but leave dry in winter. Hardy up to -5°C (for short periods). Flowering is stimulated by a winter period with relatively low temperatures.