DataSheet1_Youngia lushanensis, a new species of Asteraceae from Sichuan, China, inferred from morphology and nrITS phylogeny.docx

Youngia lushanensis (Asteraceae), a new species of Youngia, 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 ITS and on morphological comparison with related species. It is morphologically similar to Y. purpimea and Y. szechuanica, 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 Y. purpimea and Y. szechuanica. The three species Y. lushanensis Y. purpimea and Y. szechuanica, formed a basal group of Youngia, which is distributed in moist slopes in Southwest China.

产自中国西南地区四川庐山的黄鹌菜属（Youngia）一新种——庐山黄鹌菜（Youngia lushanensis），隶属于菊科（Asteraceae），本文对其进行了形态描述与图解。本研究通过对核核糖体内转录间隔区（ITS）序列的分子系统发育分析，并与近缘类群开展形态学比较，对该新种的系统位置进行了评估。该新种在形态上与紫花黄鹌菜（Y. purpimea）和四川黄鹌菜（Y. szechuanica）相似，叶背呈紫红色。但该新种与二者存在显著差异：其茎基无毛，叶缘具稀疏锯齿，叶两面均光滑无毛；每个头状花序含9-11枚小花，总苞片内层具鸡冠状突起。基于ITS序列的系统发育分析同样表明，该新种与紫花黄鹌菜（Y. purpimea）和四川黄鹌菜（Y. szechuanica）亲缘关系密切。庐山黄鹌菜、紫花黄鹌菜与四川黄鹌菜这三个物种构成了黄鹌菜属的一个基部类群，该类群分布于中国西南地区的湿润坡地。