Fig. 3

The occurrence rates of chloroplast genomic variation during speciation in Dendrobium. A Overall length of InDels for different lineages of Dendrobium with B. inconspicuum as reference; B Accumulation rates of InDels lengths every million years along branches of the Dendrobium phylogeny. Pies of 11 Dendrobium species are scaled proportionally to InDel lengths. Divergence times (myr) of 1–9 branches are estimated by Yang et al. [32]. Major branches of insertion and deletion lengths every million years are shown