Tree at the Howick Hall Arboretum [C.J. Earle, 2010.06.20].
Bark on the tree shown above [C.J. Earle, 2010.06.20].
Foliage on the tree shown above [C.J. Earle, 2010.06.20].
Map showing distribution of C. chengiana (yellow), C. fallax (green), and C. gansuensis (blue), based on sites listed in Li (2020) and on GBIF download https://doi.org/10.15468/dl.4z5543 (2024.12.10), taxa in C. chengiana sensu latu, assigned to species based on geographic location. See Google My Maps for more detail.
Cupressus chengiana
岷江柏木 Min Jiang baimu [Chinese, lit. "Min River cypress"] (Fu et al. 1999).
Type: China, Sichuan, N.W. Wenchuan Xian, W.C.Cheng 2066, 1930.11.02. Sister taxa include Cupressus fallax and C. gansuensis. C. funebris and C. tonkinensis may in turn be sister to these three taxa, forming the "Tonkinensis" major clade of Terry et al. (2018). Synonyms: Chamaecyparis chengiana (S.Y.Hu) Gaussen (1968), Cupressus chengiana var. wenchuanhsiensis Silba (1994).
Earlier authorities took a broad view of this taxon, including trees from most of northern Sichuan and southern Gansu (Fu et al. 1999, Farjon 2005, Farjon 2010), but molecular and morphological studies (Hao et al. 2006, Xu et al. 2010, Feng et al. 2017, Li et al. 2020) have shown that it includes three clearly distinct and spatially disjunct taxa, each one native to a different major watershed. Li et al. (2020) assembled an exceptionally large molecular dataset from 82 individuals of all three taxa and found that C. chengiana originated as a hybrid of C. fallax and C. gansuensis (with 38% of material from the former species and 62% from the latter). A molecular clock suggests that C. fallax and C. gansuensis diverged about 4.5 million years ago, i.e. in response to topographic changes associated with uplift of the Qinghai-Tibet Plateau; conversely the hybridization event that produced C. chengiana was about 1.34 million years ago, i.e. during an early Pleistocene glacial/interglacial cycle (Li et al. 2020). These three taxa appear to be sister to each other and they could be treated at subspecies rank, but the current fashion in Cupressus, Hesperocyparis and Juniperus is to assign species rank to sister taxa when they are morphologically distinct and spatially disjunct.
Trees to 20 m tall, branches are smooth or slightly compressed. Twigs 1.25 mm diameter, 4-sided with scale leaves. Leaves carinate, ovate, obtuse, 1 mm long. Pollen cones 2-3 mm long, broad-ovate, with 3 or 4 microsporangia. Seed cones globose, 5-10 mm diameter, comprised of 6-8 scales, each scale suborbicular, 4-6 mm diameter, wrinkled and papillate, with 5 ovate, brown seeds (Hu 1964). However, Feng et al. (2017), in a detailed morphometric study, found a mean seed cone length of 14.7 mm, a mean cone diameter of 14.0 mm, and an average of 9.06 scales per cone; although these numbers are significantly larger than those given by Hu (1964), they still indicate significantly smaller cones than on either C. fallax or C. gansuensis.
China: Sichuan: the Min He watershed (Maerki and Hoch 2020). Elevation ca. 1800 m ( GBIF 2024).
Hao et al. (2006) describe human impacts as the primary cause of decline in C. chengiana. The IUCN lists this taxon as "Vulnerable" based on "an area of occupancy of 700 km2, fewer than 10 locations, and a continuing decline in the number of mature individuals." That assessment is unduly optimistic because it dates to 2010 and conflates C. chengiana, C. fallax, and C. gansuensis. Each of the component taxa is currently (2024) likely to meet criteria for "Endangered" or "Critically Endangered", but the necessary quantitative analysis has not been done.
No data as of 2024.
The wood is regularly used for house construction and furniture production (Li et al. 2020).
No data as of 2024.
The epithet honors Chinese botanist W. C. Cheng (1908-1983).
Feng, Qiuhong, Zuomin Shi, Zhengjingru Xu, Ning Miao, Jingchao Tang, Xingliang Liu, and Lei Zhang. 2017. Phenotypic variations in cones and seeds of natural Cupressus chengiana populations in China. Chinese Journal of Applied Ecology 28:748-756, https://doi.org/10.13287/j.1001-9332.201703.001.
Gaussen, H. 1968. Les gymnospermes actuelles et fossils. Les Cupressaceés. Trav. Lab. Forest. Toulouse, Tome II, Sect. I, Vol. 1, partie II 2, fasc. 13:58, 70.
Hao, Bingqing, Wang Li, Mu Linchun, Yao Li, Zhang Rui, Tang Mingxia, and Bao Weikai. 2006. A study of conservation genetics in Cupressus chengiana, an endangered endemic of China, using ISSR markers. Biochemical Genetics 44(1–2):29–43. https://doi.org/10.1007/s10528-006-9011-8.
Hu, S.Y. 1964. Notes on the Flora of China IV. Taiwania 10: 57. Available: Cupressus Conservation Project, accessed 2019.03.01.
Li, Jialiang, Richard I. Milne, Dafu Ru, Jibin Miao, Wenjing Tao, Lei Zhang, Jingjing Xu, Jianquan Liu, and Kangshan Mao. 2020. Allopatric divergence and hybridization within Cupressus chengiana (Cupressaceae), a threatened conifer in the northern Hengduan Mountains of western China. Molecular Ecology 29(7):1250–66. https://doi.org/10.1111/mec.15407.
Maerki, Didier, and Jean Hoch. 2020. Taxonomy of the cypresses of Sichuan and Gansu. Bulletin of the Cupressus Conservation Project 9(1):3–12.
Silba, John. 1994. J. Int. Conifer Preserv. Soc. 1:25.
Terry, Randall G., Andrea E. Schwarzbach, and Jim A. Bartel. 2018. A molecular phylogeny of the Old World cypresses (Cupressus: Cupressaceae): evidence from nuclear and chloroplast DNA sequences. Plant Systematics and Evolution 304(10):1181-1197.
Xu, Tingting, Richard J. Abbott, Richard I. Milne, Kangshan Mao, Fang K. Du, Guili Wu, Zhaxi Ciren, Georg Miehe, and Jianquan Liu. 2010. Phylogeography and allopatric divergence of cypress species (Cupressus L.) in the Qinghai-Tibetan Plateau and adjacent regions. BMC Evolutionary Biology 10(1):194. https://doi.org/10.1186/1471-2148-10-194.
No data as of 2024.
Last Modified 2024-12-10
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