Gymnocalycium ritterianum

A small rare cactus with a generally solitary habit. It takes the name 'ritterianum' from the explorer Rausch, who chose it to commemorate his colleague Ritter. Its globular and flattened stem is of a grayish-green color, which changes to reddish with the prolonged exposure to intense light or in dry cold conditions. It has very evident ribs, that form pronounced tubercles, where stiff curved yellow-brown spines are formed at the ends. From spring to autumn, it blooms, at the apex of the plant, with beautiful funnel-shaped flowers of a white-pink color.