Origin of the Diplazium hachijoense complex (Athyriaceae)

Abstract

We analyzed the phylogeny of theDiplaziumhachijoensecomplex using plastidtrnL-Fand low-copy nuclear markerAK1DNA sequences. Based on allele constitution, triploid apogamous species of theD.hachijoensecomplex appeared to have originated from the hybridization of triploid apogamous species and diploid sexual species by recurrent hybridization events. These results suggested that triploid apogamous ferns can achieve hybridization with diploid sexual species by producing diploid spores with irregular meiosis in sporogenesis. Furthermore, the present study predicted the involvement of several unknown species associated with hybridization. More sampling ofCallipterisspecies from China and adjacent areas is required to determine the relationships among unknown species and theD.hachijoensecomplex.