The early evolution of the flowering plant order Apiales is discussed based on information from morphology and DNA sequences from four genes (ndhF, rbcL, atpB and matK). A model-based approach of analysis, Bayesian inference, is used to analyse the data and the results are compared with those from parsimony analysis. In particular, a new family of the order, the monogeneric Pennantiaceae from New Zealand and Australia, aids in the understanding of how the order originated. The ancestor of Apiales was probably a shrub or small tree with alternate, simple leaves, paniculate inflorescences, five-merous flowers with free petals, and drupes. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 141, 1–24.