The name of this genus comes from the Greek and literally means "curved", probably referring to the curved and climbing course of its stems. They consist in wonderful caudices, formed by a woody and rough tuber, of spherical shape but sometimes also completely asymmetrical, ovoid or elongated. This is just one of the characteristics that collectors love the most, because this allows each plant to be absolutely unique, never exactly identical to another! The caudex also assumes the important function of water reserve, allowing the plant to survive even long periods of drought. Every year, during the vegetative period, new thin and very long stems are generated from the tuber which develop with contorted and bushy course, often climbing character. Perhaps not many people know that this genus presents, inside the stems, a latex consisting of many substances including caffeic acid, useful to slow down the oxidative stress of the human body!