Juniperus brevifolia (Azores juniper) description

Juniperus brevifolia

(Seub.) Antoine 1857

Common names

Azores juniper; cedro [Portuguese].

Taxonomic notes

Originally described in 1844 by Moritz August Seubert in Flora Azorica, Volume 26 as J. oxycedrus var. brevifolia Seub. In 1857, Franz Antoine elevated it to species rank. There are two homotypic synonyms, Juniperus oxycedrus var. brevifolia Seub. and Juniperus rufescens var. brevifolia (Seub.) Endl., but neither has been used for a long time.

Juniperus sect. Juniperus. Terpene and molecular analyses place J. brevifolia sister to J. navicularis, which occurs in coastal Portugal. J. deltoides of interior Europe is also in this clade (Adams 2014). All three species were originally treated within J. oxycedrus, but molecular data have shown otherwise, as well as helping to elucidate morphological and ecological differences; see J. deltoides for further discussion. Infraspecific genetic variation was assessed in 178 individuals from 18 populations, finding differences between coastal and mountain populations (Silva et al. 2011). This genetic evidence, combined with morphological and ecological evidence, has resulted in description of three infraspecific taxa:

J. brevifolia subsp. brevifolia;
J. brevifolia subsp. maritima R.B.Elias & E.Días (2014); and
J. brevifolia var. montana R.B.Elias & E.Días (2014).

Description

Dioecious evergreen shrubs or small trees with a broad pyramidal crown of erect branches. Bark purplish brown, exfoliating in strips. Leaves needle-like, 3-10 × 1-2 mm, strongly curved, the adaxial face with two broad, white stomatal bands. Pollen shed in spring. Seed cones ripening in 2nd year, subglobose, 7-9 mm diameter, green and pruinose maturing to dark coppery brown; 3 ovoid seeds per cone (Adams 2014).

Regarding the infraspecific taxa, subsp. maritima is an erect shrub or small tree with relatively large leaves, seed cones, and seeds. Within subsp. brevifolia, var. brevifolia is a small to medium tree, while var. montana is a small prostrate shrub. Elias and Dias (2014) offer this key to the infraspecific taxa:

1.	Leaves 5.6–7.5 × 1.4–1.9 mm; seed cones 7.9–9.5 mm diameter, ripening in the first year; seeds 4.9–6.3 × 3.6–5.1 mm; erect shrub or small tree; coastal areas.	subsp. maritima
2.	Leaves 4.5–6.7 × 1.0–1.5 mm; seed cones 6.9–8.8 mm diameter, ripening in the second year; seeds 4.0–5.2 × 2.2–3.7 mm; growing at elevations above 300 m.	subsp. brevifolia
2a.	Leaves acute, horizontal to perpendicular to stem, in 3–5 whorls of three/cm; small to medium tree, with elliptical crown; growing at elevations of 300-1000 m.	var. brevifolia
2b.	Leaves acuminate, erect to horizontal, in 5–7 whorls of three/cm; small prostrate shrub; growing at elevations of 850-1500 m.	var. montana

Distribution and Ecology

Portugal: Azores; Corvo, Faial, Flores, Pico, Santa Maria, Sao Jorge, Sao Miguel, and Terceira islands; it is most abundant on Pico and Terceira islands. Found on mountain slopes at (250-)250-800(-1500) m elevation on volcanic rock (Adams 2014); the climate is almost perennially damp due to the prevailing westerly winds. It is a constituent of the Macaronesian evergreen forest, a formerly extensive vegetation type that has been greatly reduced and fragmented since humans colonized the islands (Farjon 2010).

Regarding the infraspecific taxa, subsp. maritima grows on Flores, Terceira, Pico and São Jorge islands in coastal scrubs at <100 m elevation. Subsp. brevifolia occurs on all islands except Graciosa at 300-1500 m elevation. Within subsp. brevifolia, var. brevifolia grows at 300-1000 m elevation, while var. montana grows in mountain scrub and bog at 850-1500 m elevation. The populations of subsp. maritima are small and isolated from the (usually) much larger subsp. brevifolia populations. The varieties of subsp. brevifolia commonly have adjacent ranges with narrow contact zones (Elias and Dias 2014).

The IUCN conservation assessment has varied between "Endangered" and "Vulnerable" assessments. Currently it is "Vulnerable" due to the relatively large area of occupancy, over 500 km². However the extant populations are severely fragmented and in steep decline; large mature trees are now rare and most extant populations are comprised of young, shrubby trees. The primary threats to the species include land conversion for agroforestry and livestock ranching; timber harvest; competition from invasive weeds; and climate change. However, approximately 75% of the extant populations are now protected in various nature reserves, and plans are in place to preserve habitat, control invasive species, reduce habitat fragmentation, and otherwise contribute to species conservation (Thomas 2011).

Zone 9 (cold hardiness limit between -6.6°C and -1.1°C) (Bannister and Neuner 2001).

Remarkable Specimens

No data as of 2023.03.03.

Ethnobotany

No reported uses (Adams 2014) and rare in cultivation, excepting major botanical gardens (Farjon 2010).

Observations

See the collection records on iNaturalist.

Remarks

The epithet means "short-leaved."

Citations

Adams, Robert P. 2014. Junipers of the World: The Genus Juniperus, fourth edition. Bloomington, IN: Trafford Publishing. 415 pp.

Antoine, Franz. 1857. Die Cupressineen-Gattungen Arceuthos Juniperus und Sabina. Wein: Beck. p. 16, tt. 20-22.

Elias, Rui Bento, and Eduardo Dias. The recognition of infraspecific taxa in Juniperus brevifolia (Cupressaceae). Phytotaxa 188(5):241–50. http://dx.doi.org/10.11646/phytotaxa.188.5.1.

Silva, L., R. B. Elias, M. Moura, H. Meimberg, and E. Dias. 2011 Genetic variability and differentiation among populations of the Azorean endemic gymnosperm Juniperus brevifolia: baseline information for a conservation and restoration perspective. Biochemical Genetics 49: 715–734. http://dx.doi.org/10.1007/s10528-011-9445-5.

Thomas, P. 2011. Juniperus brevifolia (errata version published in 2018). The IUCN Red List of Threatened Species. https://www.iucnredlist.org/species/30326/136559787, accessed 2022.12.21.