Origin and Habitat: Unknown, probably horticultural.

• Rebutia krainziana cv. brevispina

Description: Rebutia krainziana cv. brevispinaSN|15968]]SN|15968]] is a mutant cultivar with very sort spines. The specially notable characteristics of this cactus are the dark stem colour, emphasized by small white areoles and the bright orange flowers. But the most peculiar trait of this plant are the vestigial leaves subtending the small areoles on each tubercle. This is an ancestral trait not manifested in the normal plant. This trait is revealed thanks to a mutation that permits this odd cultivar to show the characteristic of bearing leaves, reminding us of an ancient era when its cacti ancestors were normal leafed plants.
Habit: It is a clumping globular cactus forming clusters up to 15 cm tall and wide.
Stem: Individual stems up to 6 cm tall, globose, dark green, that begins to offset in about its third or fourth year, eventually making a moderately tight clump, with the individual stems standing out a little on their own.
Tubercles: In two downward spirals, in ratio 8-13.
Spines: Extremely reduced, straw-coloured, very thin, very short, and soft, but they can still poke.
Flowers: Orange or yellow, 3,5 cm wide, develops from the base of each head, resulting in a superb display in mid season.
Blooming season: it is usually one of the earliest rebutias to flower in spring.

Cultivation and Propagation: Full sun to light shade. Water regularly in summer but do not over-water. Keep dry in winter. Hardy down to -4°C. It is better that they be repotted regularly. Repotting will increase the number and size of stems, and will increase the number of flowers produced. Repot yearly until it reaches about 100 mm in size, then every two or three years will suffice. Repotting is best done at the end of winter, but it can be done at other time, too. Do not water for a couple of weeks after repotting, in order to reduce risk of root rot via broken roots.
Propagation: Offsets, seeds