In the mountains in the southeast of Yunnan Province, botanists have described a new species of maple — Acer wenshanense. So far it is known from a single adult tree about 12 metres tall. The researchers found neither saplings nor young plants nearby, so every tree is now very valuable to science.
The path to the description stretched over a quarter of a century. In 2001, botanist Chen Yusheng of the South China Botanical Garden (Chinese Academy of Sciences), while examining the herbarium of the Institute of Botany in Beijing, noticed several fruiting specimens collected in Wenshan. The leaves and reticulate venation resembled those of Acer lofuense, but the samaras were unusual: the two wings curved inward and crossed. At the time, the researcher considered the plant a distinct variety of a known species. In 2019–2020, he searched for it during a survey of the flora of Wenshan but did not find it. The turning point came in September 2024: He Deming, an employee of the Wenshan Nature Reserve who had taken part in earlier fieldwork, managed to find the tree again and collect specimens with fruits. It was precisely these materials that made it possible to confirm that the species is distinct.
The new maple differs from its close relative Acer sino-oblongum in several features: its sepals are shorter, about 2,5 millimetres versus roughly 4, and its samaras diverge not at an angle of 70–120 degrees, as in its relative, but are curved inward. The paper with the description was published in the journal Phytotaxa in early November 2026. Its authors are Chen Yusheng and colleagues from the South China Botanical Garden and the Wenshan Reserve. The scientists propose assigning the species to the category of plants with extremely small population sizes, and in the journal it is called critically endangered.
Wenshan is not the only place in Yunnan where rare maples have survived. In 2022, new populations of the maple Acer yangbiense Acer yangbiensewere found in the Laojunshan Reserve in Wenshan, on whose earlier finds the researchers had relied. Previously this species was known only in Dali Prefecture, where all the plants numbered about 746 individuals. Such finds show how small the populations of Yunnan's rare maples are and how important it is to take every locality into account.
Propagating the species and subsequent plantings in the natural environment will be the next step, if healthy planting material can be obtained.
