Reinstatement of Loxogramme yigongensis (Polypodiaceae), an endemic species from southeastern Xizang, China

Loxogramme yigongensis, so far known only from the type specimens collected in 1965 and treated as a synonym of L. grammitoides, is reinstated. Morphologically, these two species are closely related but L. yigongensis differs in having succulent lamina, becoming rugose when dry, lamina lanceolate with acute apex, widest near middle of lamina, and costa not or slightly raised on lower surface. Molecular analyses based on five plastid loci resolved these two species as sister to each other with distinct divergence. In addition, the ploidy level of the two species are reported for the first time.