Species boundaries based on interfertility (<b>A</b>)<b>, relatedness </b>(<b>B</b>)<b>, genotypic similarity </b>(<b>C</b>) <b>and morphological similarity </b>(<b>D</b>) <b>criteria, represented on the map of the stand.</b>

<p>In A, B and C, individuals classified into the B1, P1 or G1 species, respectively, are represented by yellow triangles. Individuals classified into the B2, P2 or G2 species are represented by green diamonds. Intermediate individuals are represented by black crosses. In D, individuals classified into M1 are shown in red, individuals classified into M2 in blue and morphologically intermediate individuals are indicated by black crosses. Individuals of the M1 group are assigned to <i>Q. robur</i> and individuals of the M2 group to <i>Q. petraea</i> on the basis of current taxonomical practices.