Resolving a nearly 90-year-old enigma: The rare Fagus chienii is conspecific with F. hayatae based on molecular and morphological evidence

Dan-Qi Li; Lu Jiang; Hua Liang; Da-Hai Zhu; Deng-Mei Fan; Yi-Xuan Kou; Yi Yang; Zhi-Yong Zhang

doi:10.1016/j.pld.2023.01.003

Resolving a nearly 90-year-old enigma: The rare Fagus chienii is conspecific with F. hayatae based on molecular and morphological evidence

Plant Divers. 2023 Jan 12;45(5):544-551. doi: 10.1016/j.pld.2023.01.003. eCollection 2023 Sep.

Authors

Dan-Qi Li^{1

2

3}, Lu Jiang^{1

2}, Hua Liang^{1

2}, Da-Hai Zhu⁴, Deng-Mei Fan², Yi-Xuan Kou^{2

5

6}, Yi Yang², Zhi-Yong Zhang^{1

2

5

6}

Affiliations

¹ College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China.
² Laboratory of Subtropical Biodiversity, Jiangxi Agricultural University, Nanchang 330045, China.
³ Lushan Botanical Garden, Jiangxi Province and Chinese Academy of Sciences, Jiujiang 332900, China.
⁴ Longxi-Hongkou National Reserve, Chengdu 611830, China.
⁵ Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin 541004, China.
⁶ Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilization in Lijiang River Basin, Guilin 541006, China.

Abstract

Taxonomic uncertainties of rare species often hinder effective prioritization for conservation. One such taxonomic uncertainty is the 90-year-old enigma of Fagus chienii. F. chienii was previously only known from the type specimens collected in 1935 in Pingwu County of Sichuan Province, China, and has long been thought to be on the verge of extinction. However, morphological similarities to closely related Fagus species have led many to question the taxonomic status of F. chienii. To clarify this taxonomic uncertainty, we used the newly collected samples to reconstruct a molecular phylogeny of Chinese Fagus species against the phylogenetic backbone of the whole genus using seven nuclear genes. In addition, we examined nine morphological characters to determine whether F. chienii is morphologically distinct from its putatively closest relatives (F. hayatae, F.longipetiolata, and F.lucida). Both morphological and phylogenetic analyses indicated that F. chienii is conspecific with F. hayatae. We recommended that F. chienii should not be treated as a separate species in conservation management. However, conservation strategies such as in situ protection and ex situ germplasm preservation should be adopted to prevent the peculiar "F. chienii" population from extinction.

Keywords: Conservation; Conspecific; F. hayatae; Fagus chienii; Morphology; Phylogenetics.