Isolated intermediates - products of long distance gene dispersal, phantom hybridity or convergent evolution? The case of the half-barked Eucalyptus amygdalina

Apparent intermediates between <i>Eucalyptus amygdalina</i> and <i>E. pulchella</i> occur well outside the recognized range of the latter species. Progenies of these isolated intermediates were grown in uniform conditions with progenies of trees of <i>E. pulchella</i>, <i>E. amygdaline</i> and apparent hybrids between these two species that are found where they occur parapatrically. The isolated intermediate population proved identical with <i>E. amygdalina</i> in seedling characteristics, while the parapatric intermediates were more variable than the other populations, this variability probably being partly the result of hybridization between <i>E. amygdalina</i> and either <i>E. tenuiramis</i> or <i>E. risdonii</i>. The allopatric intermediate population is more likely to have resulted from convergence of <i>E. amygdalina</i> in the direction of <i>E. pulchella</i> than from phantom hybridity or long distance gene migration.