The Narcissus horticultural divisions are a system of classifying the cultivated varieties of the genus Narcissus (/nɑːrˈsɪsəs/), which are predominantly spring perennial plants in the Amaryllidaceae (amaryllis) family. Various common names including daffodil, narcissus, and jonquil are used to describe all or some members of the genus. The list of Narcissus horticultural divisions provided by the Royal Horticultural Society (RHS) is the standard method used to classify and describe cultivated varieties (cultivars) of Narcissus. It is widely used since the RHS is the international authority for the registration of such cultivars. For horticultural purposes, all Narcissus cultivars are split into 13 divisions, based partly upon flower form (shape and length of corona – the "trumpet" or "cup"), particularly the ratio of corona to length of perianth segments (tepals or "petals"), the number of flowers per stem, flowering period and partly upon the genetic background. Division 11 (Split-corona) with its two subdivisions was the most recent group to be described (1969). (Full list...)