Researchers from the Wuhan Botanical Garden of the Chinese Academy of Sciences have discovered a new species of Impatiens during a plant diversity survey in Zayu County, Xizang, China. The new species, named Impatiens zayuensis S. Peng, G. W. Hu & Q. F. Wang, was published in Phytotaxa on April 15.

The genus Impatiens, belonging to the Balsaminaceae family, comprises over 1,000 species worldwide, including more than 300 species recorded in China. Most of these species are found in the mountains of southwestern China, particularly in Yunnan, Sichuan, Guizhou, and Xizang.

The discovery dates back to 2017, when a research team led by Associate Professor CONG Yiyan from Hunan Normal University encountered a spurless Impatiens plant during a field survey of plant resources in Zayu County. Although no specimens were collected at the time, photographs of the plant prompted further discussions with the research group of Professor HU Guangwan from the Wuhan Botanical Garden. The researchers suspected that the plant might represent a previously undescribed species of Impatiens.

In 2024, members of Professor HU's team revisited the survey site to conduct detailed investigations and collect specimens. Through careful morphological comparison and molecular phylogenetic analysis, the plant was finally confirmed as a new species.

This new species belongs to I. sect. Racemosae Hooker & Thomson of subgenus Impatiens. It is morphologically similar to I. margaritifera Hook.f. and I. casseabriae Y.H.Tan, S.S.Zhou & B.Yang. However, I. zayuensis differs from the latter two in that it has glands on the upper stem, ovate lateral sepals with a dentate margin, a sub-dolabriform or oblong lower petal, and an oblique lower sepal mouth.

Phylogenetic analysis further revealed that I. zayuensis does not cluster with the two morphologically similar spurless species, suggesting that the spurless character may have evolved several times within the I. sect. Racemosae.

The discovery of this new species not only enriches the species diversity of Impatiens in Xizang, but also provides new material for studying the evolutionary history, adaptive radiation, and biogeographic patterns of the genus on the Qinghai-Tibet Plateau.

This study was supported by the Science and Technology Major Project of Xizang, the Second Tibetan Plateau Scientific Expedition and Research Program, the National Natural Science Foundation of China, etc.

Impatiens zayuensis. A. habitat; B. inflorescence; C-D. front view of flower; E-F. lateral view of flower; G. dissected flower (a. dorsal petal; b. lateral sepals; c. lateral united petals; d. lower sepal; e. stamens and pedicel); H. capsule and fruit stalk. I. seeds; J. leaves; K. root (Image by YUAN Taohua)

Morphological comparison of Impatiens zayuensis (A1-I1) and I. margaritifera (A2-I2). A. inflorescences; B. the upper part of the stems (showing glands); C. leaves (showing glands at the base of the leaf blade); D. front view of flowers; E. lateral view of flowers; F. lateral sepals; G. dorsal petals; H. lateral united petals; I. lower sepals (1-I1 photographed by YUAN Taohua; B2-E2 by HUANG Wen; F2-I2 by PENG Shuai)