Fig. 1

a The occurrence records of Tristaniopsis collina and T. laurina in eastern Australia, and their distributional extent indicated by the red box (inset map). Areas of significance are shown, including a number of known biogeographic barriers: the Clarence River Corridor (CRC), Manning River Valley (MRV), Hunter River Corridor (HRC), Cumberland Plain (CP), Shoalhaven River (SR), and Southern Transition Zone (STZ). b The study area in eastern New South Wales is indicated by the red box. Sample sites (n = 6) and their average population assignment proportions are represented as pie charts. Each colour represents a lineage identified by sNMF, assuming K = 4 for T. collina and c assuming K = 3 for T. laurina