DISCUSSION
Our population genetic analyses of the A. viridiflora complex within its main range across Northern China suggest a paraphyletic divergence scenario of the species complex with significant phenotypic divergence. These lineages show moderate levels of genetic differentiation and diverged from each other 168 to 239 Kya, a timing in the Middle Pleistocene that the most important climate transition has occurred, namely, the “mid-Brunhes transition” (MBT, ~400 Kya) (Ao et al., 2020). The results further indicate that both geographic isolation and selective pressures via environmental factors have contributed to the observed lineage differentiation. In the following, these findings will be discussed in more detail.