Juniperus saltuaria (Sichuan juniper, 方枝柏) description

Juniperus saltuaria

Rehder et E.H. Wilson 1916

Common names

Black seed juniper, Sichuan juniper, 方枝柏 fang zhibai [Chinese].

Taxonomic notes

This is one of the central Asian turbinate-cone junipers, a taxonomically complex group subdivided mainly on the basis of molecular studies that have almost all been performed by R. P. Adams and coworkers; the principal such studies were by Adams and Schwarzbach (2012, 2013); see the cladogram of Juniperus for a summary of relationships in the group. Although the cladogram places J. saltuaria as sister to J. fargesii, there is limited confidence in this result, as the two taxa have not been otherwise conflated in the long and confusing record of names for central Asian junipers. Indeed, J. saltuaria has been regarded as a good and distinct species ever since its 1916 description.

Syn: Sabina saltuaria (Rehder et Wilson) Cheng et Wang 1961 (Farjon 1998). Type: China, Sichuan, Min River, Songpan, mountains N of town, E. H. Wilson 3013.

Gene-flow work comparing J. tibetica with three closely-related other junipers of the Qinghai-Tibetan Plateau, J. convallium, J. saltuaria and J. przewalskii, has given us a glimpse of the complex evolutionary history of the turbinate-cone juniper clade, finding evidence of "both incomplete lineage sorting and gene flow after species divergence" (Li et al. 2011; see this source for considerable further insights regarding this group).

Description

Monoecious shrubs, or trees to 20 m tall and 100 cm dbh; with one or several stems, and spreading branches of dense foliage forming a rounded or irregular crown. Bark on larger stems exfoliating in longitudinal strips, weathering grey-brown or grey. Foliage-bearing twigs, curved or drooping, the ultimate branchlets quadrangular, 1.0-1.7 mm thick, covered with appressed scale leaves. Leaves decussate or 3-whorled, imbricate, decurrent, 1-2 × 0.7-1 mm, triangular-rhombic, obtuse, ridged abaxially with an ovate gland near the base; weakly amphistomatic, with adaxial stomata in two bands separated by an inconspicuous midrib; leaves green, without cuticular wax. Pollen cones solitary, terminal on short twigs, subglobose, 2-3 mm diameter; microsporophylls 6-8, decussate, peltate-orbicular, with entire hyaline margins, bearing 2-3 pollen sacs near lower margin. Seed cones terminal on short erect twigs, globose or ovoid, maturing in the second season 5-8 × 4-8 mm, lustrous blue-black or purplish black and soft. Bract-scale complexes 6, decussate, entirely fused; bract tips usually hidden or minute; surface smooth; scale tissue succulent, resinous. Seeds 1 per cone, irregularly ovoid-globose, 3.5-7 × 3-5 mm, grooved, with resin pits, yellowish to light brown (Farjon 2010).

Distribution and Ecology

China: Gansu, Qinghai, Sichuan, NW Yunnan; E Xizang (Tibet). It grows in rocky areas on sites that are not subject to severe periodic drought, at elevations of 2100 to 4600 m in high montane to subalpine conifer forest, usually with Abies, Larix potaninii, or Picea over an understorey of Rhododendron, Sorbus, and Salix; also in more or less pure groves or with J. convallium, J. pingii, or J. squamata, and Rhododendron, in the forest-tundra econtone; also in mixed shrub communities with Rhododendron, Salix, Cotoneaster, Berberis, Lonicera, Spiraea, etc. (Farjon 2010). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).

Remarkable Specimens

The oldest reported living tree was 272 years old (crossdated) in 2016, growing in the Wolong Nature Reserve of Sichuan at 3700 m elevation (Liu et al. 2019, citing Li et al. 2015).

Ethnobotany

Not much is known. It may be used for firewood or locally used for timber; it is unknown in horticulture (Farjon 2010). Wilson (1913) stated that "it is valued for building purposes."

Observations

Remarks

Saltuarius is Latin for "forester," so the epithet means it is a juniper of the forests.

Citations

Farjon, Aljos. 2010. A Handbook of the World's Conifers. Leiden, Netherlands: Brill Academic Publishers.

Li Zhonghu, Jiabin Zou, Kangshan Mao, Kao Lin, Haipeng Li, Jianquan Liu, Thomas Kallman, and Martin Lascoux. 2011. Population genetic evidence for complex evolutionary histories of four high altitude juniper species in the Qinghai–Tibetan Plateau. Evolution 66(3):831-845, doi:10.1111/j.1558-5646.2011.01466.x.

Li Z., Liu G., Wu X., and Wang X. 2015. Tree-ring-based temperature reconstruction for the Wolong Natural Reserve, western Sichuan Plateau of China. International Journal of Climatology 35:3296–307.

Liu, Jiajia, Bao Yang, and David B Lindenmayer. 2019. The oldest trees in China and where to find them. Frontiers in Ecology and the Environment 17(6): 319–22. https://doi.org/10.1002/fee.2046.

Rehder and E. H. Wilson. 1916. Juniperus saltuaria. P. 61 in Sargent, C. S. (ed.), Plantae Wilsoniae, Publications of the Arnold Arboretum No. 4. Cambridge: University Press. Available at the Biodiversity Heritage Library, accessed 2020.01.22.

Wilson, E. H. 1913. A Naturalist in Western China, V. 2. London: Methuen & Co. Ltd. P. 13, available at the Biodiversity Heritage Library, accessed 2020.01.22.