Dryopteris × subdiffracta (Dryopteridaceae), a new natural hybrid fern from Guangxi, China

A new natural hybrid fern, Dryopteris×subdiffracta (Dryopteridaceae), is reported from Guangxi, China. Molecular phylogenetic analysis based on DNA sequences from the low-copy nuclear marker <i>Ak1</i> and plastid genome revealed respectively that <i>D.polita</i> and <i>D.diffracta</i> are parents of the new hybrid, with <i>D.polita</i> as the maternal parent. Cytometric analysis of the nuclear DNA content indicated that <i>D.×subdiffracta</i> might be a diploid hybrid. Morphologically, <i>D.×subdiffracta</i> shares a high degree of similarity with <i>D.×subreflexipinna</i> from Taiwan, especially in zigzag-shaped rachis and deflexed pinna stalks. However, <i>D.×subdiffracta</i> is distinguishable in the degree of lamina division and shapes of lamina and pinnulets. A comprehensive taxonomic description accompanied by line drawings are provided.