“…a,b), even when they occur in sympatry and gene flow is evident (Hipp et al ., , ; Cavender‐Bares et al ., ; Eaton et al ., ). Numerous studies using nuclear DNA markers – including microsatellites, random amplification of polymorphic DNA markers, or low‐copy nuclear genes – present similar evidence (Craft et al ., ; González‐Rodríguez et al ., , ; Curtu et al ., ; Cavender‐Bares & Pahlich, ; Craft & Ashley, ; Holtken et al ., ; Zhang et al ., ). By contrast, chloroplast DNA, which is maternally inherited (Dumolin et al ., ), typically shows extensive introgression (Whittemore & Schaal, ), and haploptypes are shared across species (Fig.…”