Rebutia canigueralii subs. rauschii
Sulcorebutia rauschii is a well known miniature clustering species, that readily forms clumps of many heads with characteristic short pectinate spines. The crested form is very rare and nice.
Stems are up to 5 cm in width. .The stem is covered by flat tubercles (5mm wide) which vary in colour between dark green and violet. Flowers are 20 - 50 mm long, 35 - 50 mm wide; floral tube funnel-shaped yellowish green with tan coloured scales, tepals deep magenta with a clearer throat.
Sulcorebutia is a mountainous cactus with a thick taproots and is susceptible to overwatering, it grows rather slowly and need a very good drainage to avoid rotting. It requires also an appropriate air circulation and is sometime grafted to avoid root problems.It loves a very permeable, coarse mineral soil. Water moderately in the growing season, keep dry during the winter rest. Needs a full sun, or half shaded exposure (light shadow may be useful in the hottest summer days)
Give an occasional high potassium liquid feed during the active growing period.
It is a fine plant for a rock garden or container, contrasts well with agaves, yuccas, and low-growing flowering Cactus.
For watering cacti, the golden rule is to make sure the soil is completely dry before watering! This will stop the roots from rotting. It is advised to always use a pot with a drainage hole so that excess water can get drained out. If kept in a sunny area, you will need to water it once every week. If it is in a semi shaded or filtered light area, you might need to water it once in 2 weeks.
Cacti like soil that is well aerated and fast draining. You can fertilise the cactus in the summer months when it is in its growing season. During the winters it is best to cut back on any fertiliser and let the plant rest.