Scientists have described Xua hongheensis in the dry-hot valleys of the Red River in China’s Yunnan Province. Differences in its structure and DNA evidence led them to place it in a separate genus within the dogbane family, Apocynaceae.
It is a perennial twining herb with hairy stems. Its small flowers, about a centimetre across, resemble yellow stars. The stems can reach three metres in length.
Researchers from the Xishuangbanna Tropical Botanical Garden and the Institute of Botany of the Chinese Academy of Sciences compared the plant with its close relatives. Alongside its physical features, they studied chloroplast DNA and regions of nuclear DNA. The findings were published in the Journal of Systematics and Evolution.
A genus groups together related species. In this case, the authors proposed a separate genus, Xua, containing one described species, Xua hongheensis. The genus honours botanist Xu Zaifu, a former director of the Xishuangbanna Tropical Botanical Garden.
So far, the plant is known only from scattered locations in the Red River basin. The researchers provisionally assessed it as Data Deficient: more field observations are needed before its extinction risk can be evaluated.
