Small is beautiful
Rebutia heliosa. Also known as Aylostera heliosa.
The smallest flowering cactus in my collection.
The most remarkable thing about this one is that it grows at between 2,500 and 3,000 metres in the Andes in Bolivia. Thats almost 10,000 feet.
That probably explains why it is so small. Like many high alpine plants it has a very low profile to better enable it to survive the gale force winds at that altitude.
There are more buds coming and it is said to flower very well