Schnabeliajiuzhaigouensis (Lamiaceae, Ajugoideae), a new species from Sichuan, China.

Schnabeliajiuzhaigouensis C. Liu, F. Zhao & C.L. Xiang, a new species from north-eastern Sichuan, China, is described, based on both morphological and molecular phylogenetic evidence. Morphologically, the new species is mostly similar to S.terniflora, but can be readily distinguished by its habit, ovate to lanceolate-ovate leaf blades, the presence of 5-8 lateral veins on each side of the mid-rib and distinct characteristics of the floral structure, including oblong upper lip and lateral lobes of the lower lip, with the middle lobe being cuneate. In addition, the nutlets are puberulent and lack reticulate venation. Molecular phylogenetic analyses place the new species at a basal position within the genus Schnabelia. The new species is categorised as Data Deficient (DD) according to the IUCN Red List Categories and Criteria. A key to all species of Schnabelia is also provided.