| Two key phases in the evolution of South Chinese tracheophyte leaves can be recognized. |
| This indicates an expansion of CPK gene family after the divergence of flowering plants from the remainder of the tracheophyte lineage. |
| A well-documented fossil assemblage includes acanthodian, placoderm, chondrichthyan, and cephalaspid fishes, tracheophyte remains, eurypterids, ostracods, and molluscs. |
| Our findings suggest that tracheophyte leaf disparity and diversity were decoupled, and that they were under different selective regimes. |
