Characterizing and distinguishing the earliest woody euphyllophytes based on secondary xylem anatomy: method development and application

The metrics developed here for quantifying secondary xylem anatomy are effective in demonstrating conspecificity and in separating distinct woody taxa, especially in combination with data on the primary xylem and xylem rays. They provide a new method for assessing the taxonomic placement of fossils with incomplete preservation, opening up a new avenue for exploring fossil plant diversity and for characterizing anatomy, with implications for the evolution of plant development.