Tuber is a botanical term. It is a kind of metamorphosis of plant stems, which is lumpy, hence the name. Since it is a stem, it has the main characteristics of plant stems, such as buds and leaf scars. The potato we often eat is the most typical tuber. One of the underground abnormal stems is a transverse stem with short internodes, which has different shapes and often has an irregular mass of meat, and stores certain nutrients to survive adverse climatic conditions. The root system occurs from the bottom of the tuber, and the nodes are sunken downward, such as eye sockets, and buds are born in them, but they are not obvious, and the scales degenerate or fall early, such as Pinellia ternata, Gastrodia elata, and potatoes.