Abstract
Sinosenecio yaanensis K.Huang & Z.X.Fu (Asteraceae) is described as a new species from Tianquan County, western Sichuan, China. It resembles S. chienii and S. homogyniphyllus in its scapigerous habit and palmately veined ovate to ovate-cordate radical leaves, but differs in several stable traits. Its leaves are subcoriaceous with whitish blotches adaxially and a purplish red abaxial surface, whereas S. chienii has submembranous blades that are pale green on the abaxial surface, while S. homogyniphyllus has smaller membranous leaves. Sinosenecio yaanensis produces 3-10 (vs. 2-9 in S. chienii and mostly solitary in S. homogyniphyllus) capitula, ca. 8 (vs. 10-12 and 8-17) ray florets, and lacks a pappus (vs. absent or rarely with short hairs). Phylogenetic analyses based on chloroplast genomes and ITS sequences place S. yaanensis within the Sinosenecio-tussilaginoid assemblage corresponding to the Tussilagininae subtribe, clustering with S. chienii and S. homogyniphyllus.