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 fallax
大渡河柏木 Dadu He baimu [Chinese], the Dadu River cypress (Long and He 2022).
Although described by Franco (1969), the taxon was emended by Maerki and Hoch (2020), and a new type designated. Type: China, Sichuan, "valley of Tung River" (Dadu River), E.H.Wilson 2106, 1300-2600 m elevation, Jul-1908. 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. gansuensis. 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).
There is one hybrid--literally one, the "Jiange Cypress" a single tree planted several centuries ago 3.75 km northeast of downtown Hanyang, Sichuan (32.1534°N, 105.5370°E). Its name is Cupressus × wangii J.Hoch, Maerki & Rushforth (2020). Synonyms: C. jiangensis N.Zhao (1980), C. chengiana var. jiangensis (N.Zhao) Silba (1981), C. chengiana subsp. jiangensis (N.Zhao) Silba (2005). The pollen parent was C. funebris, which is abundant in the area; the ovuliferous parent was a C. fallax, likely a cultivated individual (Hoch and Maerki 2020).
Evergreen monoecious trees up to 30 m tall, strongly branched. Bark brownish-red. Foliage more or less pendant. Twigs 1-1.2 mm thick, quadrangular with scale leaves, brownish-gray, wrinkled. Leaves imbricate, monomorphic, gray-green, bearing a distinct gland, acute or obtuse. Pollen cones 2-3 × 1.2-1.5 mm with 8-12 scales. Seed cones subglobose to oblong, green when young, grayish brown at maturity, comprised of 8-10 woody scales, 15-25 x 15-20 mm (Franco 1969, Maerki and Hoch 2020). Feng et al. found the seed cones to average 18.6 mm long and 16.9 mm diameter, bearing an average of 10.05 scales with an average of 63 seeds per cone. These figures are all significantly different from the closely-related taxa C. chengiana and C. gansuensis.
China: Sichuan, the Dadu River watershed, in the following districts: Barkam, Jinchuan, Danba, Kangding, Luding and Xiaojin (Maerki and Hoch 2020). Elevations range from 1380-2640 m (GBIF 2024).
Hao et al. (2006) describe human impacts as the primary cause of decline in C. fallax. 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. Each of the component taxa is currently (2024) likely to meet criteria for "Endangered" or "Critically Endangered", but the necessary quantitative analysis seems not to have been done.
No data as of 2024.
Hao et al. (2006) report that forests of this species have been preserved in the Baiwan area "because this plant was a sacred tree for the minorities there", but provide no further detail.
No data as of 2024.
Fallax is Latin for "deceptive", so perhaps Franco (1969) named it for its similarity to another cypress.
Franco, J. D. A. 1969. On Himalayan-Chinese cypresses. Portugaliae Acta Biologica, Ser.B 9:183-195 (p.190).
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.
Long, Tinglun and Fei He. 2022. A Brief Discussion on the Minjiang and Daduhe Cypresses. Green Tianfu 10:20-27.
Hoch, Jean, and Didier Maerki. 2020. About Cupressus jiangeensis N.Zhao. Bulletin of the Cupressus Conservation Project 9(1):15–22.
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. 1981. Phytologia 49:394.
Silba, John. 2005. J. Int. Conifer Preserv. Soc. 12:58.
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.
Zhao, Neng. 1980. Species nova generis cupressi. Acta Phytotax. Sin. 18:210.
No data as of 2024.
Last Modified 2024-12-12
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