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. 2 n = 22. 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.
Lvs in whorls of 3, jointed at the base, crowded, linear, loose or spreading, pungent, 6-18 mm, with a median white stripe above; cones axillary, bluish or black, 6-13 mm thick, mostly 3-seeded. Circumboreal, s. in Amer. to Pa., Wis., Minn., the Rocky Mt. states, and irregularly to S.C. and s. Ind. Nearly all of our plants belong to the var. depressa Pursh, the common Amer. phase of the sp.; decumbent but not prostrate, forming flat-topped circular patches mostly 0.5-2 m tall and several m wide; lvs spreading or ascending, mostly straight, (6)10-18 mm, the white stripe narrower than each margin; mostly in dry, rocky, or otherwise poor soil; occasional more arborescent
specimens, with a ±definite central axis, have been mistaken for the arborescent Eurasian var. communis, which has the white stripe on the lvs at least as broad as each margin. The high-northern, circumboreal var. montana Aiton reaches only the ne. margin of our range, as on the coast of N.S. and the coast and mts. of n. Me.; it is prostrate or nearly so and trailing, with oblong, abruptly short-pointed, incurved and imbricate lvs 6-10 mm, these with a broad white stripe, evidently wider than each margin (var. alpina; var. saxatilis, misapplied; J. sibirica; J. nana).
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.