Syn: J. tetragona Schlechtendal var. osteosperma Torrey 1857; J. californica Carrière var. utahensis Engelmann; Sabina osteosperma (Torrey) Antoine; S. utahensis (Engelmann) Rydberg (Adams 1993), J. utahensis (Silba 1986). It is reported to hybridize with J. occidentalis in northwestern Nevada (Vasek 1966).
"Shrubs or trees monoecious, to 6(-12) m, multi- or single-stemmed; crown rounded. Bark exfoliating in thin gray-brown strips, that of smaller and larger branchlets smooth. Branches spreading to ascending; branchlets erect, 3-4-sided in cross section, about as wide as length of scalelike leaves. Leaves light yellow-green, abaxial glands inconspicuous and embedded, exudate absent, margins denticulate (at 20×); whip leaves 3-5 mm, glaucous adaxially; scalelike leaves 1-2 mm, not overlapping, or, if so, by less than 1/10 their length, keeled, apex rounded, acute or occasionally obtuse, appressed. Seed cones maturing in 1-2 years, of 1-2 sizes, with straight peduncles, globose, (6-)8-9(-12) mm, bluish brown, often almost tan beneath glaucous coating, fibrous, with 1(-2) seeds. Seeds 4-5 mm" (Adams 1993).
Similar species: J. scopulorum has similar range but is generally found at higher elevations. It is dioecious, usually single-stemmed, generally a darker (sometimes glaucous) green, and the leaf margins are entire at 20X magnification.
USA: Arizona, California, Colorado, Idaho, Montana, New Mexico, Nevada, Utah and Wyoming at 1300-2600 m elvation on dry, rocky soils and slopes. It is the dominant juniper of Utah (Adams 1993). See also Thompson et al. (1999). Hardy to Zone 5 (cold hardiness limit between -28.8°C and -23.3°C) (Bannister and Neuner 2001).
Diameter 221 cm, height 9 m, crown spread 8 m, located in Duchesne County, Utah (American Forests 1996).
I know of no data, but based on observations, I am fairly confident that it occasionally exceeds 1,000 years.
Preliminary studies found a high frequency of absent rings and poor circuit uniformity (that is, a ring varies in width around the circumference of the tree). Consequently, the species has been little used in dendrochronology.
Common and easily seen at Arches, Canyonlands, Capitol Reef, Bryce Canyon, and Zion National Parks in Utah, and Great Basin National Park in Nevada. In fact, it is difficult to travel in the Great Basin or Colorado Plateau without seeing landscapes covered with this tree, usually in pure stands or accompanied only by Pinus monophylla.
The epithet osteosperma means "bony seed."
Farjon (2005) provides a detailed account, with illustrations.
Last Modified 2012-11-28