Multiple origin of the tropical forest tree family Icacinaceae.

Analyses of DNA sequences from four genes (ndhF, rbcL, atpB, and 18S rDNA) and morphological data show that the members of the tropical forest tree family Icacinaceae do not have a common origin. All of the genera earlier placed in Icacinaceae are euasterids but placed in the following three different orders: Garryales, Aquifoliales, and Apiales. Icacina and related genera are members of Garryales and, pending more data, are still best treated as Icacinaceae (sensu stricto). The genera related to Aquifoliales are placed in Cardiopteridaceae and a new family, Stemonuraceae. The genus Pennantia is a member of Apiales and the family Pennantiaceae is recognized. Morphological characters delimiting these groups are discussed. Twenty-six new ndhF sequences were obtained for the study (25 from former Icacinaceae and 1 from Cardiopteris).