Juniperus coahuilensis (redberry juniper) description

Juniperus coahuilensis

(Martinez) Gaussen ex R.P. Adams 1993a

Common names

Roseberry juniper (Adams 1993b), redberry juniper.

Taxonomic notes

Formerly described as a variety of J. erythrocarpa Martinez, and elevated to species rank by Gaussen (1968). Gaussen failed to cite a basionym, thus his description was invalid, an error corrected by Adams (1993a). Leaf terpenoid and RAPD analysis by Adams (1994) indicate that hybridization and introgression with J. angosturana has occurred. Syn. J. erythrocarpa Cory var. coahuilensis Martinez 1946 (Farjon 2005). J. arizonica was formerly described as a variety, Juniperus coahuilensis var. arizonica R.P. Adams 1994.

"Hybridization with Juniperus pinchotii occurs in Big Bend National Park, Texas (Adams and Kistler 1991), and possibly near Saltillo, Mexico. Reports of hybridization with J. ashei have been refuted (Adams 1975)" (Adams 1993b).

Description

"Shrubs or trees dioecious, to 8 m, single-stemmed to 1 m or branched at base; crown flattened-globose to irregular to round. Bark gray to brown, exfoliating in long ragged strips, that of small branchlets (5-10 mm diam.) smooth, that of larger branchlets exfoliating in strips, or occasionally in flakes. Branches spreading to ascending; branchlets erect, 3-4-sided in cross section, ca. 2/3 as wide as length of scalelike leaves. Leaves green to light green, abaxial glands elliptic to ovate, at least 1/4 of glands (on whip leaves) with an evident white crystalline exudate, margins denticulate (at 20´); whip leaves 4-6 mm, glaucous adaxially; scalelike leaves 1-3 mm, not overlapping or if so, by less than 1/4 their length, keeled, apex acute, spreading. Seed cones maturing in 1 year, of 1 size, with straight peduncles, globose to ovoid, 6-7 mm, rose to pinkish but yellow-orange, orange, or dark red beneath glaucous coating, fleshy and somewhat sweet, with 1(-2) seeds. Seeds 4-5 mm" (Adams 1993b). Distinguished from J. arizonica by distribution, and by having large whip-leaf glands that are at least half as long as the associated leaf (Adams 2008, Farjon 2010).

Distribution and Ecology

Coahuila and USA: Texas (Farjon 2005). Its persistence in grasslands may be due to its unusual ability to resprout from cut or fire-killed stumps (Farjon 2005, citing pers. comm. from R.P. Adams).

Remarkable Specimens

No data as of 2023.03.03.

Ethnobotany

Observations

Remarks

Citations

Adams, Robert P. 1975. Gene flow versus selection pressure and ancestral differentiation in the composition of species: analysis of populational variation in Juniperus ashei Buch. using terpenoid data. J. Molec. Evol. 5:177-185.

Adams, Robert P. 1993a. Nomenclatural note: Juniperus coahuilensis (Martinez) Gaussen ex R.P. Adams. Phytologia 74:413.

Adams, Robert P. 1993b. Juniperus. Flora of North America Editorial Committee (eds.): Flora of North America North of Mexico, Vol. 2. Oxford University Press. This document is available online. Go to http://www.efloras.org, click on "Flora of North America," and search for "Juniperus."

Adams, Robert P. 1994. Geographic variation and systematics of monospermous Juniperus from the Chihuahuan desert based on RAPDs and terpenes. Biochem. Syst. Ecol. 22:699-710.

Adams, Robert P. 2008. Junipers of the World: The Genus Juniperus. Second edition. Trafford Publishing. Brief versions of the descriptions are available online at Adam's website, www.juniperus.org.

Adams, R. P. and J. R. Kistler. 1991. Hybridization between Juniperus erythrocarpa Cory and Juniperus pinchotii Sudworth in the Chisos Mountains, Texas. The Southwestern Naturalist 36: 295-301.

Gaussen, H. 1968. Les gymnospermes actuelles et fossils. Les Cupressaceés. Trav. Lab. Forest. Toulouse, Tome II, Sect. I, Vol. 1, partie II 2, fasc. 10:1-222.