Hydrangea medogensis (Hydrangeaceae), a new species from Xizang (Tibet), China.

Based on field surveys, examination of herbarium specimens, and molecular phylogenetic analyses, the present study described a new species, Hydrangea medogensis sp. nov. (Hydrangeaceae), from Medog County, Xizang Autonomous Region, China. Phylogenetic analyses indicated that H. medogensis was placed in Clade 1 as a distinct lineage, sister to the remainder of the clade. Morphologically, the new species is most similar to H. stylosa but can be distinguished by the following key characteristics: fertile flowers with a globose calyx tube constricted at the mouth; calyx teeth triangular, occasionally oblong-ovate, 0.6-1 mm long; adaxial leaf surface covered with two types of soft hairs (long and short); ovary more than 4/5 inferior, nearly completely inferior; and seeds with a very narrow wing around the margin. The taxonomic status of the new species was established based on integrated morphological and molecular evidence.