Youngia lushanensis, a new species of Asteraceae from Sichuan, China, inferred from morphology and nrITS phylogeny

<i>Youngia lushanensis</i> (Asteraceae), a new species of <i>Youngia</i>, is described and illustrated from Lushan in Sichuan, Southwest China. Its systematic position is evaluated based on a molecular phylogenetic analysis of the nuclear ribosomal <i>ITS</i> and on morphological comparison with related species. It is morphologically similar to <i>Y. purpimea</i> and <i>Y. szechuanica</i>, with purplish red abaxially leaves. But it differs from the latter two in that its caudex are glabrous, leaf margins are sparsely dentate, and being glabrous on both surfaces, 9-11 florets in each capitulum, and inner phyllaries are crested. Phylogenetic analysis based on ITS also showed this new species is closely related with <i>Y. purpimea</i> and <i>Y. szechuanica.</i> The three species <i>Y</i>. <i>lushanensis Y. purpimea</i> and <i>Y. szechuanica</i>, formed a basal group of <i>Youngia</i>, which is distributed in moist slopes in Southwest China.