The COM clade is non-monophyletic; constituent families should
be placed in malvids
The COM clade, as circumscribed by two studies
(Matthews &Endress, 2006; Zhu et al., 2007 ), contains approximately 19,000
species, or approximately one-fifth of all superrosids (APG IV,
2016 ). Despite rapid progress in elucidating the major branches of
superrosid phylogeny, the position of the COM clade has been a subject
of much debate. We found that the COM clade was non-monophyletic, and
the three constituent families appeared with malvids based on coalescent
and concatenation-based methods (Fig. 5, 6 ). The sister
relationship between Celastrales and Malpighiales was strongly
supported, and Oxalidales was sister to a clade comprising Sapindales,
Malvales, and Brassicales with strong support in concatenation
phylogeny, which was also reported by Zhao et al. (2016) . In
our coalescent tree, Celastrales and Malpighiales were also sisters with
strong support, and Oxalidales and Sapindales formed a clade with LPP =
0.89. Thus, the CM clade and Oxalidales should be members of malvids
rather than fabids, which is also supported by floral features shared
between the COM orders and malvids (e.g., the inner integument of the
ovule, contorted petals, Matthews & Endress, 2006 ).