Phylogenetic relationship of 16 asterids determined using 14 conserved mitochondrial protein-coding sequences. Posterior probability distributions calculated by the BLAST program are indicated at the branch points. Scale bar represents the number of nucleotide substitution per site. The following mitochondrial genome sequences were used for the phylogenetic analysis: A. reptans, A. syriaca, B. hygrometrica, C. annuum, C. paramensis, C. lanceolata, D. carota subsp. sativus, H. annuus, H. niger, I. nil, M. guttatus, N. tabacum, P. grandiflorus, R. stricta, S. miltiorrhiza, and V. macrocarpon.