Abstract
Sileneophioglossa Huan C. Wang & Feng Yang, a new species of Caryophyllaceae, is here described and illustrated based on morphological and molecular evidence. The new species was found in Sichuan and Yunnan provinces, southwest China. Phylogenetic analysis based on ITS sequences showed this new species belongs to section Cucubaloides. Morphologically, it resembles S.phoenicodonta and S.viscidula, which were also found in the southwest China, but clearly differs from the latter two species by having 5-7 mm long calyces with sparsely hirtellous and short glandular hairs, white petals, linear limbs and lobes, and absent or oblong-linear coronal scales. A distribution map and a table with morphological diagnostic characters of new species and its closest relatives are provided, as well as a preliminary conservation assessment of S.ophioglossa under the IUCN criteria.