Amblyanthus chenii, a new species and generic record from Xizang, China

<p><em>Amblyanthus chenii </em>(Primulaceae; Myrsinoideae)<i>, </i>a new species discovered growing in the understory of primeval forests in Medog County, southeast Xizang, China, is described based on morphological evidence. This is also the first generic record of <i>Amblyanthus</i> in China. The new species is most similar morphologically to<i> A. multiflorus</i> based on its axillary inflorescence and connate filament, but it differs in its 2-4 cm long condensed panicle and up to half adnation of its sepals and petals. <i>Amblyanthus chenii</i> can also be easily distinguished from other congeneric species by various morphological differences. Phylogenetic analysis based on nuclear ribosomal ITS and six plastid markers indicates that <i>Amblyanthus chenii </i>and <i>Amblyanthopsis burmanica </i>form a clade that is nested within the large pantropical genus<i> Ardisia</i> and is sister to the <i>Ardisia</i> subgenus <i>Crispardisia</i>. The close relationships among <i>Amblyanthus</i>, <i>Amblyanthopsis,</i> and<i> Ardisia</i> subg. <i>Crispardisia </i>are strongly supported by their shared synapomorphy of crenulate leaves with marginal glands.</p>