Oak (genus Quercus),comprising approximately 469 species of ornamental and timber trees and shrubs in the beech family (Fagaceae), is a dominant woody lineage in forest ecosystems across the Northern Hemisphere.
During their herbarium specimens survey of Fagaceae in 2021, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) and Yunnan University found some oak materials with characteristics not seen in any known species of Quercus. After consulting relevant literature and herbarium specimens from major herbaria in China and key international herbaria, they determined that the specimens differ from all published species of Quercus, and represent a new species.
The new species is named Quercus zhekunii in honor of Prof. ZHOU Zhekun of XTBG, a distinguished botanist who has dedicated his career to the systematics, biogeography and fossil history of East Asian Fagaceous plants and has made significant contributions to understanding Cenozoic flora changes in East Asia.
The new species was published in Nordic Journal of Botany.
Quercus zhekunii is an evergreen small tree or shrub, 2.0–4.0 m tall. The dense fused fasciculate and uniserate trichomes on the leaf abaxial surface of Q. zhekunii resemble those of Q. kingiana. However, its distinctively concave primary and lateral veins on the leaf adaxial surface, along with the prominent backward-recurved leaf blade and leaf margin, make it morphologically distinct from any known species in Q. sect. Ilex.
The new plant fruits biennially (pistillate flowers to acorns requiring two years to mature). It flowers in March and fruits in the next October to early November, and acorns are scarce.
Quercus zhekunii grows on open limestone hills with brown lime soil at elevations of 450–830 m above the sea level. It is found at four known locations on open limestone rocky cliffs, tops or ridges in the northern tropical region of East Asia. It is scattered across western to northwestern Guangxi
“Given its vulnerability to habitat degradation, which significantly impacts its populations in the karst regions of southwestern China, we recommend that Q. zhekunii be classified as ‘Endangered' (EN) according to the current IUCN red list categories and criteria,” said HUANG Jian of XTBG.
Quercus zhekunii M.Deng & J.Huang, sp. nov. (A, C) Fresh leaves and a current year young twig with the young male catkins and pistillate flowers from herbarium collection of J. Huang et al. K71-56 (HITBC), (B, D) fresh twigs with cupules and acorns on secondary year branches (type specimen:M. Deng & Y, Tu 27503 [HITBC]), (E) open limestone habitat. (Image by HUANG Jian)
HUANG Jian Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: huangjian@xtbg.ac.cn
Published: 01 October 2024
