Background: The species-rich genus Impatiens is mainly distributed throughout much of tropical Africa, India, southwest Asia, southern China and Japan. There are more than 270 species recorded in China, most of which are restricted to the southwest. An unknown species of Impatiens was collected from Yunnan, southwest China.
Results: Impatiens pandurata Y. H. Tan & S. X. Yu, a new species of Balsaminaceae from Jinping County and Malipo County, Yunnan, China is similar to I. apalophylla and I. clavigera in having racemose inflorescences, 4 lateral sepals, hammer-shaped capsules and ellipsoid seeds, but differs in having leaves with oblanceolate blades aggregated at the top of the stem, 3-5-flowered racemes, a yellow lower sepal without reddish patches, yellowish flowers, and a dorsal petal with stalks at the base. Molecular phylogenetic analyses of sequences from both nuclear ribosomal and plastid genes confirm that this new species is distinct from morphologically similar species previously recorded.
Conclusion: With the support of careful morphological studies and phylogenetic analysis, I. pandurata is a species new to science.
Keywords: Balsaminaceae; Impatiens; Morphology; New species; Phylogeny.