RELATIONSHIP OF THE ORDER APIALES TO SUBCLASS ASTERIDAE: A RE-EVALUATION OF MORPHOLOGICAL CHARACTERS BASED ON INSIGHTS FROM MOLECULAR DATA

Abstract

Phylogenetic relationships involving the angiosperm order Apiales (Apiaceae and Araliaceae) are troublesome at nearly every taxonomic level and have eluded several generations of botanists. Because of difficulties in interpreting and polarizing morphological character states at deeper phylogenetic levels, most studies in Apiales have focused on relationships between the two families and among/within the apialean genera. In the present study, however, recent contributions from molecular analyses are reviewed and combined using a ‘supertree’ approach to test traditional hypotheses of relationships involving Apiales, and to re-evaluate assumptions of character-state evolution in the order. Results from this study confirm that Apiales form a monophyletic group with Pittosporaceae (along with Griselinia G. Forst., Melanophylla Baker, Torricellia DC. and Aralidium Miq.), and should be transferred out of subclass Rosidae (away from both Cornales and Sapindales) to the Asteridae (in a position close to Asterales and Dipsacales). These findings are also supported by several lines of morphological, anatomical, and phytochemical evidence, and provide a more satisfactory framework for interpreting relationships and character-state evolution within the major clades of Apiales.