银杉 yin shan (Wu and Raven 1999).
Synonymy (Wu and Raven 1999):
Cathaya nanchuanensis Chun et Kuang 1958;
Cathaya argyrophylla (Chun et Kuang) Greguss;
Tsuga argyrophylla (Chun et Kuang) de Laubenfels et Silba 1984.
"The original description was by Chun & Kuang, Bot. Zhurn. (Moscow & Leningrad) 43: 464. 1958. However, the name was not validly published there because two species were described simultaneously and the type species was not indicated" (Wu and Raven 1999).
Genetics work by Ge et al. (1998) and Wang and Ge (2006) indicates that compared to other conifers, Cathaya has rather low genetic diversity, but there are significant differences between populations that support the existence of at least four refugia where the species occurred during the last Pleistocene glaciation, and that indicate the populations have remained isolated since that time.
Monoecious evergreen trees. Monopodial trees to 20 m tall and 40 cm DBH with a columnar, straight trunk. Bark on mature trees dark gray, irregularly flaking. Shoots both long and short, as in Larix, the long shoots with alternate rapid and slow growths that result in sets of leaves alternating with denser tufts; the lateral short shoots bear solitary leaves packed densely, appearing clustered. Shoots are yellow-brown, initially densely gray-yellow pubescent, aging dark yellow and glabrous; short shoots topped with pale, orbicular or subsquare leaf scars. Winter buds are light yellow-brown, ovoid or ovoid-conical. Leaves are dark green, 4-6 cm × 2.5-3 mm on long branchlets, but nearly clustered into a whorl on short branchlets where usually not longer than 3 cm. They are spirally arranged, radially spreading, linear-oblanceolate with entire, slightly revolute margins and a rounded apex, slightly curved or straight, longitudinally grooved adaxially, with 2 white abaxial stomatal bands separated by an elevated midvein, having 1 vascular bundle 1 and 2 resin canals. Leaf surface puberulent, densely pubescent along grooves. Pollen cones 1-3 from axillary buds on branchlets. Pollen 2-saccate, with visible cap on pole. Seed cones are green, maturing a dark brown, ovoid or ellipsoid, 3-5 × 1.5-3 cm. They are axillary, sessile, initially erect but becoming pendulous, maturing in the first year but often persistent for many years. They each have 13-16 woody, stiff, suborbicular or compressed seed scales. The scales are orbicular-ovate, 1.5-2.5 × 1-2.5 cm, densely pubescent on exposed part, dehiscent at maturity, persistent. The bracts, 1/4-1/3 as long as the scales, are spatulate with a tapering apex. Seeds are dark green mottled with light green, slightly appressed, obliquely ovoid, 5-6 × 3-4 mm with a membranous yellow-brown wing that is obliquely ovate or elliptic-ovate, 1-1.5 cm × 4-6 mm. Cotyledons 3 or 4. Germination epigeal. 2n = 24* (Wu and Raven 1999).
China: SE Sichuan (Nanchuan Xian, Wulong Xian), N Guizhou (Daozhen Xian, and Tongzi), S Hunan, NE Guangxi (Jinxiu Yaozu Zizhixian, Longsheng Gezu Zizhixian), at 900-1900 m elevation in mountains, usually on open slopes and ridges (Wu and Raven 1999). The populations described as nanchuanensis occur in Yunnan, mostly in the Kunming area and SE (Vladimir Dinets email 1998.01.02). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).
McNamara (2001-2005) provides an engaging account of his visit to these trees in the Jinfu Shan south of Nanchuan, Sichuan.
The discovery of this species in 1955 caused a minor scientific sensation, similar to that which accompanied the discoveries of Metasequoia glyptostroboides in 1945, Wollemia nobilis in 1994, and Cupressus vietnamensis in 2001. The first group of 1,040 trees was discovered in the Huaping Nature Reserve in Sanmen, a town in Longshen Gezu Autonomous County (Xinhua 2004).
Chun and Kuang. 1962. Acta Bot. Sin. 10(3): 245-246.
McNamara, William A. 2005. Three conifers south of the Yangtze. http://quarryhillbg.org/Articles/Three%20Conifers/Three%20Conifers.htm, accessed 2007.10.23, now defunct.
Xinhua. 2004. More ancient pine trees discovered in Guangxi. People's Daily, 2004.11.25. http://english.peopledaily.com.cn/200411/25/eng20041125_165101.html, accessed 2007.10.23.
Zeng, Xiaolian. Stamp, issued 1992.03.10. Image formerly available at http://www.bupt.edu.cn/stamp/plant/92_3.htm, accessed 1999.04.12, now defunct.
The species account at Threatened Conifers of the World.
Farjon, Aljos. 1990. Pinaceae: drawings and descriptions of the genera Abies, Cedrus, Pseudolarix, Keteleeria, Nothotsuga, Tsuga, Cathaya, Pseudotsuga, Larix and Picea. Königstein: Koeltz Scientific Books.
- Provides a detailed account, with illustrations.
Fu, L.G. and Chen, S.Z. 1981. Discovery and designation of Cathaya argyrophylla. Plant Journal (Zhiwu Zazhi) 4: 1-42.
Hou H.Y. 1983. The geographical distribution of natural and cultural vegetation in the humid subtropics of China. P. 311-316 in W. Holzner, M.J.A. Werger and Ikusima I. (eds.), Man's Impact On Vegetation no. 5.
Hu, Y.S. and Wang, F.H. 1984. Anatomical studies of Cathaya (Pinaceae). American Journal of Botany 71(5): 727-735.
Li-kuo, F. and Jian-ming, J. (eds) 1992. China Plant Red Data Book. Rare and Endangered Plants 1. Beijing: Science Press.
Pant, D.D., and N. Basu. 1977. A comparative study of the leaves of Cathaya argyrophylla Chun & Kuang and three species of Keteleeria Carriere. Botanical Journal of the Linnean Society 1975(3): 271-282.
Last Modified 2017-12-29