Cytotype coexistence leads to triploid hybrid production in a diploid–tetraploid contact zone of <i>Chamerion angustifolium</i> (Onagraceae)

Abstract

Our results indicate that tetraploids regularly coexist with diploids in the contact zone and that this coexistence is likely promoted by both strong reproductive isolation and asymmetric intercytotype mating between diploid and tetraploid C. angustifolium.