Linaceae is a family of flowering plants. The family is cosmopolitan, and includes approximately 250 species. There are 14 genera, classified into two subfamilies: Linoideae and Hugonioideae (often recognized as a distinct family, the Hugoniaceae). Leaves of Linaceae are always simple; arrangement varies from alternate (most species) to opposite (in Sclerolinon and some Linum) or whorled (in some Hesperolinon and Linum). The hermaphroditic, actinomorphic flowers are pentameric, or very rarely tetrameric (e.g. Radiola linoides, Linum keniense).