Phylogenetic analysis of the genus Miscanthus and its relative genera (Poaceae) in China

Miscanthus is an important plant resource in China, which has energy plant value, bio-material value, and ecological value. However, the taxonomy of Miscanthus remains poorly defined. To clarify the phylogenetic relationships among the Miscanthus species found in China, here we describe their morphological characters, simple sequence repeats (SSRs), inter simple sequence repeats (ISSRs), and trnL-F and rpl16 gene sequences. We identified M. sacchariflorus and M. lutarioriparius as the closest relatives of M. sinensis and M. floridulus, all of which constituted a major group. At the molecular levels, M. lutarioriparius and M. sacchariflorus were always grouped to form a monophyletic group. M. floridulus appeared as a stable secondary clade of M. sinensis. M. nepalensis, M. nudipes, and M. paniculatus were separated from the major group and more closely linked to an outgroup. M. paniculatus fell into an isolated position outside of the major group. Therefore, our findings support placing M. sacchariflorus and M. lutarioriparius in Miscanthus, treating M. lutarioriparius as a variety of M. sacchariflorus, treating M. floridulus as a subspecies of M. sinensis. We do not support merging M. nepalensis and M. nudipes into Miscanthus and propose the recognition of Diandranthus as a standalone genus, which includes D. nepalensis and D. nudipes. We do not support merging M. paniculatus into Miscanthus, and we support the recognition of Rubimons as a separate genus, including R. paniculatus. These data should help with efforts to evaluate and use Miscanthus germplasms.