The name Acanthocalycium is derived from the Greek words "ácantha" meaning "thorn/spine", and "cályx" that means "spiky chalice". The genus Acanthocalycium was first described by Curt Backeberg in the 1930s. These cacti that grow from the Argentine Andes to the Pampas, due to the climatic diversity (humid due to the proximity of the Parana River and the sea, dry for inland areas), have the characteristic of possessing a strong adaptability to a wide range of temperatures. The plants of this genus have a green-gray stem, initially globular which over time assumes a columnar habit. Acanthocalycium is a decorative species that is appreciated for its beauty and for the particular bright colors of its abundant blooms. It is not one of the most demanding cactus, regarding soil: use a well draining, sandy-clay one ( common cactus mix will be okay), and choose a pot deep enough to contain its taproot. You can place it inside or outside, but remember it needs a very bright and, if possible, airy place. During the vegetative season (spring and summer), water regularly without exceeding (or roots may rot); during winter, avoid watering: when kept dry, this cactus is hardy to freezing temperatures. Following these few instructions, you hardly will have to face mealybugs and red spiders, the most common parasites of this cactus. To sum up, Acanthocalycium can give you great satisfactions: not only it is a cactus of unique beauty, but you also will be able to grow it fast with minimal effort!