Ixonanthaceae

This small family of 2 or 3 Old World rain-forest genera was already recognized as a separate suprageneric taxon by PLANCHON (1847) and PLANCHON & KLOTZSCH (1856), who relegated it to the affinity of Ochnaceae, later correctly referred to Linaceae as a subfamily Ixonanthoideae by HUB. WINKLER (1931) and finally recognized as a family of its own by EXELL & MENDONÇA (1951). As to the number of genera contained in the family, there is no unanimity of opinion. FORMAN (1965: 523) referred 8 genera to the family, but NOOTEBOOM (1967) argued that several belong to Simaroubaceae. After careful consideration 3 genera are admitted here in Ixonanthaceae sensu stricto: Cyrillopsis Kuhlm. from South America, Ochthocosmus BENTH. (incl. Phyllocosmus KLOTZSCH) from tropical America and Africa, and Ixonanthes JACK from Indo-Malesia. The three genera form a close-knit group. They are all small and the wide distribution in the tropics points to a high age of the group.