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 gansuensis
None are listed, but for consistency with Cupressus chengiana, it would logically be called 白龙江柏木 Bailong Jiang baimu [Chinese], the Bailong River cypress.
Type: China, Gansu, "opposite Hanban village, Zhugqu county, Gannan pref.", T.P.Wang 14286, 2000 m elevation, 1951.07.11. As shown by molecular and morphological studies (Hao et al. 2006, Xu et al. 2010, Feng et al. 2017, Li et al. 2020), sister taxa include Cupressus chengiana and C. fallax. 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). C. funebris and C. tonkinensis may in turn be sister to these three taxa, forming the "Tonkinensis" major clade of Terry et al. (2018). No synonyms.
Plants, form not described, presumably trees. Bark not described. Twigs not described. Foliage not described. Pollen cones not described; pollen released in January. Seed cones glaucous when young, maturing brown and opening in one year (Maerki and Hoch 2020). Feng et al. (2017) found the seed cones to average 16.2 mm long and 15.5 mm diameter, significantly larger than C. chengiana and smaller than C. fallax. The seeds are also significantly larger, average 1.6 mm long, vs. 1.3 mm in the other two species.
China: Gansu and Sichuan, the Bailong River watershed (Maerki and Hoch 2020). One specimen has a stated elevation: 1000 m ( GBIF 2024).
Hao et al. (2006) describe human impacts as the primary cause of decline in C. gansuensis. The IUCN lists C. chengiana 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. Li et al. (2020) assert that C. gansuensis would satisfy the IUCN classification of “Endangered”, but do not offer a rationale for this determination.
No data as of 2024.
No data as of 2024.
No data as of 2024.
The epithet refers to Gansu, which holds most of the species' known distribution.
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.
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.
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.
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 2024-12-14
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