This Rebutia of unknown species is hardly noticeable until it blooms. The intense, uniform red of the flowers makes it hard to capture a clear, detailed photo. Although the quality of this photo leaves something to be desired, I chose it to post because I love the way the flower seems to be floating in air.
Since the reclassification of five genera into the Rebutia genus, there are about 60 species. Many have red flowers, but orange, yellow and white flowers are also common. Some collectors avoid this genus because many of the species are finicky and require special care. This is not the case with this cactus. I do not give this particular cactus any special treatment other than occasionally adding a drop of vinegar to its water to increase the acidity levels and help the soil to release minerals.