Juniperus rushforthiana
Rushforth's juniper.
As is common with all of the turbinate-seed-cone junipers, the circumscription of J. rushforthiana is based mainly upon molecular analyses. Molecular analyses are most reliable when multiple lines of evidence converge on a common endpoint, but, as all of the analyses to date have been performed by R. P. Adams and his co-workers (a 2020 review found no references to this taxon, excepting those authored by Adams), there is limited context with which to evaluate their significance. Described in 2008 as a variety of J. indica (Adams et al. 2008), Farjon (2010) reduced it to synonymy with that species. However, analysis using multiple regions of both nuclear and chloroplast DNA places it sister to J. recurva, in a clade sister to J. indica (Adams and Schwarzbach 2012, 2013). Adams et al. (2008), using multiple sources of molecular and essential oil data, placed it in a clade with J. indica. These analyses suggest that J. rushforthiana is about as different from J. indica and J. recurva as they are from each other, a reasoning that leads to species rank for this taxon. These three taxa all occur in the Himalaya, with J. recurva having the widest range, J. indica a more insular and disjunct range, and J. rushforthiana having the smallest range, restricted to western Bhutan, where it occurs with both of the other species. The taxa are readily distinguished by morphology.
Type: Bhutan, Soe, at Soe Tajitang campsite; a tree 15 m tall at elevation 3475 m, Rushforth 0802 (= Adams 8140).
Dioecious trees to 20 m tall and 70 cm dbh, usually single-stemmed with a crown of ascending branches. Bark on mature trees dark grey, but exfoliating to reveal an orange inner bark. Both decurrent (whip) and scale-like leaves, dark green, the whip leaves primarily on young plants, borne in whorls of 3, 3-8 mm long, acuminate, ascending. The scale leaves are decussate or in whorls of 3, 1.2-2 mm long, rhombic, closely appressed, with a central or basal gland bearing a narrow extension almost to the obtuse leaf tip. Seed cones erect, subglobose to turbinate, 10-13 mm diameter, brown maturing in 2 years blackish brown, with 1 seed per cone. Pollen is shed in April to May (Adams 2014).
The two collections have been in western Bhutan, where it occurs in dry open forests at 2800 to 4600 m elevation; speculated to occur in neighboring Tibet, India: Sikkim, and Nepal (Adams 2014).
The species has not been recognized by the IUCN and thus has no formal conservation status. Per IUCN criteria, it would likely be assessed as "Data Deficient" due to very limited knowledge of its distribution.
No data as of 2023.03.03.
Used for fuel and incense in Buddhist temples (Adams 2014).
The epithet honors British conifer botanist Keith D. Rushforth (b. 1953). He collected two trees from eastern Bhutan, and these were used for the molecular analyses reported by Adams et al. (2008).
Adams, R. P., J. A. Morris, and A. E. Schwarzbach. 2008. Taxonomic affinity of Rushforth’s Bhutan juniper and Juniperus indica using SNP’s from nrDNA and cp trnC-trnD, terpenoids and RAPD data. Phytologia 90(2):233–245.
Adams, R. P., and A. E. Schwarzbach. 2012. Taxonomy of the turbinate shaped seed cone taxa of Juniperus, section Sabina: sequence analysis of nrDNA and four cpDNA regions. Phytologia 94(3):388-403 (includes Adams' publication of J. rushforthiana).
Adams, R. P., and A. E. Schwarzbach. 2013. Taxonomy of the turbinate shaped seed cone taxa of Juniperus, section Sabina: Revisited. Phytologia 95:122–124.
Adams, Robert P. 2014. Junipers of the World: The Genus Juniperus, fourth edition. Bloomington, IN: Trafford Publishing. 415 pp.
Farjon, Aljos. 2010. A Handbook of the World's Conifers. Leiden, Netherlands: Brill Academic Publishers.
Last Modified 2023-03-03
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