Juniperus mucronata

R.P.Adams (2000)

Common names

No data as of 2026-04-14.

Taxonomic notes

Type: near Maicoba, Sonora, elev. 1180 m (Adams 2000). Syn. J. blancoi var. mucronata (R.P.Adams) Farjon, Sabina mucronata (R.P.Adams) Y.Yang & K.S.Mao.

Some authorities (e.g. Farjon 2005) treat this taxon as a variety of J. blancoi. However, Adams (2000) shows that J. blancoi and J. mucronata have highly disjunct ranges, substantially different terpene makeups, and slightly different morphology (heartwood color and presence/absence of mucronate leaf tips). The RAPD data presented by Adams (2000) distinguish J. blancoi and J. mucronata and indicate that they are both distinct from J. scopulorum. Adams et al. (2006) return to the problem and present a cladogram based on RAPD data for the two varieties of J. blancoi, J. mucronata, and J. scopulorum. The data indicate that the two varieties of J. blancoi are sister, and are in turn sister to J. mucronata.

Description

Evergreen, dioecious, shrubby tree 8-10(-15) m tall and 50 cm diameter. Bark smooth, soon exfoliating in small flakes, on larger stems fissured, rough, exfoliating in thin strips; red-brown or purple, turning grey. Branches spreading or ascending, forming a pyramidal crown that becomes broad or irregular in older trees. Ultimate branchlets lax, 4-25 × 0.8-1.3 mm, quadrangular, covered with scale leaves. Leaves decussate, imbricate, 1.3-2 × 0.7-1 mm, free, margins (hyaline-)entire, apex mucronate, glands conspicuous, large, usually inactive; leaves grey-green to yellow-green. Seed cones terminal on short (3-6 mm) branchlets, green maturing in 1-2 years to a glaucous purple-red, dark blue or tan, subglobose to reniform or bilobed, 5-7 × 5-9 mm, interior soft-pulpy, seeds 1-2(-5) per cone, 3-5 × 2-4 mm, grooved and ridged with small resin pits near base, light brown with a darker hilum (Farjon 2005). The heartwood is bright purple rather than purplish brown (Adams 2000).

Distribution and Ecology

Mexico: only known from the Maicoba/Yecora area near the Sonora/Chihuahua border (a conifer hotspot; see also Pinus yecorensis), where it occurs on slopes 30-60 m above the Maicoba River and neighboring streams, growing on basalt with Hesperocyparis lusitanica, Juniperus deppeana and Quercus spp. (Adams 2000).

Remarkable Specimens

No data as of 2026-04-14.

Ethnobotany

No data as of 2026-04-14.

Observations

See "Distribution and Ecology", above.

Remarks

The epithet refers to the mucronate leaf tips.

Citations

Adams, R. P. 2000. Systematics of smooth leaf margin Juniperus of the western hemisphere based on leaf essential oils and RAPD DNA finger printing. Biochemical Systematics and Ecology 28:149-162.

Adams, R. P., M. S. González-Elizondo, M. González-Elizondo, and E. Slinkman. 2006. DNA fingerprinting and terpenoid analysis of Juniperus blancoi var. huehuentensis (Cupressaceae), a new subalpine variety from Durango, Mexico. Biochemical Systematics and Ecology 34: 205-211.

See also