Sp. Pl. 2: 1040. 1753.
Shrubs or small trees dioecious, to 4 m (if trees, to 10 m), multistemmed, decumbent or rarely upright; crown generally depressed. Bark brown, fibrous, exfoliating in thin strips, that of small branchlets (5–10 mm diam.) smooth, that of larger branchlets exfoliating in strips and plates. Branches spreading or ascending; branchlets erect, terete. Leaves green but sometimes appearing silver when glaucous, spreading, abaxial glands very elongate; adaxial surface with glaucous stomatal band; apex acute to obtuse, mucronate. Seed cones maturing in 2 years, of 2 distinct sizes, with straight peduncles, globose to ovoid, 6–13 mm, bluish black, glaucous, resinous to obscurely woody, with 2–3 seeds. Seeds 4–5 mm. 2n = 22.
Alta., B.C., Man., N.B., N.S., N.W.T., Nfld. and Labr. (Nfld.), Nunavut, Ont., P.E.I., Que., Sask., Yukon, Alaska, Ariz., Calif., Colo., Conn., Ga., Idaho, Ill., Ind., Maine, Mass., Mich., Minn., Mont., N.C., N.Dak., N.H., N.Mex., N.Y., Nev., Ohio, Oreg., Pa., R.I., S.C., S.Dak., Utah, Va., Vt., Wash., Wis., Wyo., Eurasia.
Juniperus communis is the most widespread juniper species, and many subspecies and varieties have been described. A major study, including chemical characters, is needed to clarify the taxonomy. J. D. A. Franco (1962) recognized four subspecies (here considered varieties); two of these—var. communis and var. hemisphaerica (J. Presl & C. Presl) Parlatore—do not occur in the flora and a fifth, recognized here, was not treated by Franco.
The seed cones of Juniperus communis are used to flavor gin.
Varieties 5 (3 in the flora).
|1||Seed cones 9–13 mm, longer than leaves.||Juniperus communis var. megistocarpa|
|1||Seed cones 6–9 mm, shorter than leaves.||> 2|
|2||Glaucous stomatal band on adaxial leaf surface 2 or more times as wide as each green marginal band; spreading to matlike shrubs; leaves linear-lanceolate, to 2 mm wide, apex acute to obtuse and mucronate.||Juniperus communis var. montana|
|2||Glaucous stomatal band on adaxial leaf surface about as wide as each green marginal band; prostrate, low shrubs with ascending branchlet tips (occasionally spreading shrubs, rarely small trees); leaves linear, to 1.6 mm wide, apex acute and mucronate to acuminate.||Juniperus communis var. depressa|