Native to Paraguay, Gymnocalycium mihanovichii is commonly called the "Plaid Cactus" for the beautiful pattern of banding and ridges on the plants body. It also can turn a deep reddish purple in strong light or when cold. It produces white or pink flowers in spring and summer. A cultivar of G. mihanovichii called "Hibotan" is the ever popular "Moon Cactus". The bright red or yellow Hibotan lack enough chlorphyll to grow on their own so they are commonly grafted.
      The picture above is one in my garden. It was taken in winter and the purple color was outstanding! I also recently acquired a pinkish orange colored one from B & B Cactus Farm on it's own roots and I've successfully degafted a purple Hibotan. Update: The pink one is actually a G. Mihanovichi var friedrichii, though considered by some to be a completely seperate species known as Gymnocalycium stenopleurum.

Flowering in June	A white flowered one	A potted one flowering	Flower buds
Flower closeup	Cultivar "Hibotan"	Pink one from B & B