The Bachelor's button (Kerria japonica) belongs to Rosaceae (the Rose family). It is a small deciduous tree that is distributed throughout Japan, as well as the Korean Peninsula and China. This tree can reach about 2 m in height, and the stems are slender. The leaves are ovate and alternate. The bright yellow flowers come in April to May. The Japanese name "yama-buki" comes from the way its branches sway in the wind, and is said to be a corruption of the Japanese name "yama-buri". It is called "棣棠花" (di tang hua) in Chinese.