Perennial, evergreens, dioecious (or sometimes monoecious), prostrate to erect shrubs or trees. Roots fibrous, often exposed along cracks in rocks. Crowns strict (in young J. virginiana) to rounded or flat-topped (J. virginiana var. silicicola); branches variously oriented but not planar; bark reddish brown to gray, fibrous and exfoliating in strips, or rarely exfoliating in rectangular plates (J. deppeana). Twigs variously oriented, not flattened (not planar). Leaves persisting 3-5 years, of four types: (1) subulate (acicular or awn-shaped); (2) decurrent-blade deciduous (with an abscission layer between the blade and sheath, sections Caryocedrus Endl. and Oxycedrus Spach); (3) whip-leaves, (decurrent without an abscission layer between the blade and sheath, section Sabina Spach); and (4) scale leaves (section Sabina Spach). Whip-leaves are found on juvenile foliage and/or at the tips of rapidly growing shoots (but occasionally an entire mature tree will have only whip-leaves, and one species, endemic to Cuba, J. saxicola, has only whip-leaves). Scale leaves are closely appressed, decussate or ternate, often both decussate and ternate on the same branch. Foliage light to dark green, or often blue or silver glaucous, turning reddish to purple in some species in the winter. Leaf margins entire to denticulate (at 20-40× magnification). Stomatal bands on the adaxial surface of the leaves range from none (apparent) to one or two. All leaves have a single gland sometimes not visible, the glands vary from elongate to hemispherical (J. ashei), several species have ruptured glands that exude a white crystalline deposit. Pollen cones oblong, 3-5 mm, light tan to brown. Seed Cones maturing in 1 or 2 years, persisting for several months to a year after maturity depending on bird predation pressure. Seed Cones axillary or terminal, sessile to short peduncled, globose and ‘‘berry-like’’; 3-20 mm in diameter, scales all fused, fleshy to fibrous to obscurely woody, indehiscent, blue black, blue, rose, copper red, brown, brownish blue, purplish brown, usually with a blue or glaucous hue. Seeds wingless, 1-13 per cone, light tan to brown, with two hilum scars covering from ¼ to ¾ of the seed. Cotyledons several to numerous.

The genus is the source of numerous cultivars that are widely used for landscaping around the world. Mutants or ‘‘sports’’ are very common and are likely due to single gene mutations. Rare mutations affecting the plant habit and foliage are present in all species. Many of the ‘‘sports’’ have been given formal names or else incorrectly ascribed to hybridization or introgression.

Due to the widespread exaggerations of the degree of hybridization, this topic is discussed after each treatment. Gymnocarpy (bare seeds protruding from the cone) is occasionally found in most junipers, particularly in the SW United States. This condition is due to insect larvae predation (see Zanoni, 1978).

Finally, it should be noted that aberrant specimens may be almost impossible to identify without chemical or molecular data. At present, I recognize 18 species, 5 varieties, and 3 formas of Juniperus in Canada and the United States.

Dioecious. Large Shrub To Small Tree, 3-8 m, often with a single stem to 1 m, with flattened-globular or irregular crowns. Trunk Bark brown, thin, exfoliating in long ragged strips. Branches ascending to erect in shrubs, but spreading in trees. Branch bark scaly, ashy gray. Stumps sprouting after burning or cutting. Leaves decurrent (whip) and scale. Whip- and scale-leaf margins denticulate (20× magnification), white glaucous on adaxial leaf surface. At least ¼ or more of the whip-leaf glands with a white crystalline exudate. Seed Cones rose to pinkish but yellow orange, orange or dark red beneath the white-blue glaucous bloom, soft and juicy, globose to ovate, 6-7 mm diameter, 1(-2) seeded. Seeds 4-5 mm long, the hilum scar pale brown, approx. ½ as long as seed. Pollen Shed late fall to early winter. Fig. 1.

Common Name: Arizona juniper.

Distribution: United States. Arizona: South of the Mogollon Rim; southwestern New Mexico. Mexico. (Fig. 2).

Habitat: Bouteloua grasslands and adjacent rocky slopes; 980-1600 (-2200) m. Northeastern Sonora.

Status: abundant and weedy in many areas. It sprouts from cut stumps.

Uses: fence posts.

Adams et al. (2006) recently reviewed the taxonomy and on the basis of combined nrDNA and trnC-trnD sequence data, plus Random Amplified Polymorphic DNAs, and terpenoids and concludes that J. coahuilensis var. arizonica merits recognition at the species level as J. arizonica. Juniperus arizonica and J. coahuilensis hybridize in the trans-Pecos, Texas area and in southwestern New Mexico (Adams, 2017).

The type for J. ashei consisted of one male and three female specimens (Hall, 1954). Hall (1954) selected a female specimen (acc. number 22520, dated Sept. 16, 1923, UNC) and designated it as the lectotype.

Cupressus sabinoides Kunth, Nov. Gen. Sp. 2: 3. 1817. Juniperus sabinoides (Kunth) Nees, Linnaea 19: 706. 1847, non Griseb. (1846)

Sabina sabinoides Small, Fl. S.E. U. S. 33: 1326, (1903).

Juniperus sabinoides Sarg., Silva 10: 91. 1896, non Griseb. (1846).

Juniperus occidentalis Hook. var. texana Vasey, (Cat. Forest Trees U.S. 37) Rep. Commiss. Agric. 1875: 185. 1876.

Juniperus occidentalis Hook. var. conjugens Engelm., Trans. Acad. Sci. St. Louis 3: 590. 1878

Juniperus tetragona Moench var. oligosperma Engelm., Trans. Acad. Sci. St. Louis 3: 590. 1878

Juniperus mexicana Spreng. in part, see Zanoni, 1978.

Dioecious. Trees with broad, bushy rounded or irregularly open crown, to 15 m, with a single trunk branching at 1-3 m or occasionally branching at the base. Trunk Bark exfoliating in thin brown strips. Branches brown but usually with a greywhite fungus. Leaves both whip- and scale-like. Whip-leaves with a raised, hemispherical gland (not prominent on scale leaves). Whip- and scale-leaf margins denticulate (20× magnification). Seed Cones ovoid to subglobose, maturing in one year, dark blue and glaucous, 6-9 mm in diameter 1(2-3) seeded. Seeds 4-6 mm long. Chromosome Number 2n = 22 (Irving, 1980). Pollen Shed Dec-Feb. Fig. 3.

Common NameS: Mountain cedar, rock cedar, post cedar, Mexican Juniper, Ashe juniper.

Distribution: United States: Arkansas, Oklahoma, Texas. Northern Mexico, Fig. 4.

Habitat: limestone glades and bluffs, 150-600 m.

Status abundant on limestone in central/west Texas, range is expanding; regarded as a weed in Texas.

Uses: source of Texas cedar wood oil (Adams, 1987), fence posts.

All of the material cited by Buchholz (1930) was collected on limestone bluffs, above the White River, near Sylamore, Arkansas. It is clear in Buchholz (1930) that his illustration is of J. ashei var. ashei, with the hemispherical glands on the whip-leaves (Fig. 3). See Adams and Baker (2007), Adams (2008a), Adams (2014) for further taxonomic considerations.

Sabina californica (Carrière) Antoine, Cupress.-Gatt.: 52. 1857.

Juniperus pyriformis A. Murray ex Lindl., Gard. Chron. 1855: 420. 1855.

Juniperus cedrosiana Kellogg, Hesperian 4: 3. 1860.

Juniperus cerrosianus Kellogg, Proc. Calif. Acad. Sci. 2: 37. 1863.

Juniperus californica Carrière fo. lutheyana J. T. Howell & Twisselm., Four Seasons 2(4): 16. 1968.

Juniperus. occidentalis sensu Parl. non Hooker

Dioecious (Rarely Monoecious, 1.9%). Shrubs multi- (seldom one) stemmed shrub-tree, 2-8 m, with round crown. Trunk Bark on twigs (5-10 mm diameter) brown or gray, not exfoliating in scales or flakes. Branches, ultimate branchlets approx. as wide as scale-leaf length; scale leaves closely appressed and generally flattened, branchlets terete. Leaves both whip and scale. Leaf glands conspicuous. Whip- and scale-leaf margins denticulate (20× magnification). Seed Cones bluish brown, white glaucous, reddish brown, beneath glaucous bloom, (7-)9-10(-13) mm, maturing in 1 year. Seeds 1(2-3) per cone (avg. 1.3), 5-7 mm long. Pollen Shed Jan-March.

Common Name: California juniper.

Distribution: United States: Arizona, California, Nevada. Mexico: Baja California (Fig. 6).

Habitat: dry, rocky slopes and flats; 750-1600 m.

Status common and expanding its range (Miller and Rose, 1995).

Uses: none known, possibly fence posts.

Two chemical (volatile leaf oils) races were described by Vasek and Scora (1967) and reconfirmed by Adams et al. (1983). These two chemo-types were not found using the volatile wood oils test (Adams, 1987). To date, no morphological character or any DNA polymorphisms appear to be correlated with the chemical races.

Juniperus erythrocarpa Cory, Rhodora 38: 186-187. 1936. Juniperus pinchotii var. erythrocarpa (Cory) J. Silba, Phytologia Mem. 7: 35. 1984.

Dioecious. Trees large shrub to small tree, 3-8 m, often with a single stem to 1 m, with flattened-globular or irregular crowns. Trunk Bark brown, thin, exfoliating in long ragged strips. Branches ascending to erect in shrubs, spreading in trees. Branch bark scaly, ashy gray. Stumps sprouting after burning or cutting. Leaves both whip and scale. Whip- and scale-leaf margins denticulate (20×), white-glaucous on adaxial leaf surface. At least ¼ or more of the whip-leaf glands with a white crystalline exudate. Seed Cones rose to pinkish but yellowish orange, orange or dark red beneath the whitish blue glaucous layer, soft and juicy, globose to ovate, 6-7 mm diameter, 1(-2) seeded. Seeds 4-5 mm long, the hilum scar pale brown, approx. ½ as long as seed. Pollen Shed late fall - early winter. Fig. 7.

Common Name: Rose fruited juniper.

Distribution: 980-1600 (-2200) m, United States: trans-Pecos Texas. Mexico: common in northern Mexico around the margins of the Chihuahuan Desert (Fig. 8).

Habitat: Bouteloua grasslands and adjacent rocky slopes.

Status abundant and increasing.

Cory (1936) collected his type specimen from the base of Mt. Emory, in the Basin, Big Bend National Park from a tree with bright red seeds cones. Unfortunately, this a hybrid zone between J. coahuilensis and J. pinchotii (see Adams and Kistler, 1991) and his specimen is clearly a hybrid. Hybridization between J. coahuilensis and J. monosperma appears likely in Arizona (see J. monosperma). Hybridization between J. coahuilensis and J. pinchotii occurs in the Big Bend National Park, Brewster Co., Texas (Adams and Kistler, 1991) and possibly near Saltillo, Mexico. Juniperus arizonica and J. coahuilensis hybridize in the trans-Pecos, Texas area and in southwestern New Mexico (Adams, 2017).

Uses: fence posts. It sprouts from cut stumps.

See Adams, 2014 for synonymy.

The taxonomy of J. communis in North America has recently been reviewed and revised based on morphology, Random Amplified Polymorphic DNAs and nrDNA SNPs (Adams, 2008b, 2014) and five varieties were recognized for North America.

This variety is common in Europe and naturalized in New England, New York, West Virginia, may also be present in Pennsylvania and Virginia (Adams et al., 2016). Hybridizes with J. communis var. depressa (Adams et al. 2016). Figure 9.1 - 9.4 show DNA verified J. communis. var. communis from West Virginia and Maine.

Common Name: Common juniper.

Dioecious. Low Shrubs with upturned branchlets. Trunk Bark brown, exfoliating in wide strips or plates. Branches spreading and upturned. Leaves acicular, imbricate to open, curved, boat-shaped, tips apiculate to mucronate, 5-7 mm × 1.6 mm. Glaucous stomatal band twice as wide as each green leaf margin. Seed Cones 8-9 mm, larger than leaf length, dark blue when mature (2-3yrs).

Seeds 1(2) per cone. Pollen Shed spring. Fig. 10.

Common Name: Queen Charlotte Island juniper.

Distribution: Calvert Island to Queen Charlotte Islands, Canada and north to Chichagof Island, Alaska, (Fig. 11).

Habitat: sphagnum bogs.

Status at present, the habitat (sphagnum bogs) seems conserved, so this variety does not appear to be threatened nor endangered.

Uses: none known.

Juniperus canadensis Lodd. ex Burgsd., Anleit. Sich. Erfzieh. Holzart. 2: 124. 1787. Juniperus communis L. var. canadensis (Lodd. ex Burgsd.) Loudon, Arbor. Frutic. Brit. 4: 249. 1838.

Juniperus depressa Raf. ex M’Murtrie, Florula Louisvill., 219. 1819.

Juniperus intermedia Schur, Verh. Mitth. Siebenburg. Vereins Naturwiss. Hermannstadt 2: 169.1851.

Sabina multiova Goodwyn, Amer. Bot. (Binghamton) 37(4): 152. 1931.

Dioecious. Prostrate Or Low Shrubs with ascending branchlet tips (or occasionally a spreading shrub to 3 m). Trunk Bark brown, exfoliating in wide strips or plates. Branches erect to ascending. LEAVES acicular, upturned, rarely spreading, linear, acuminate, tips acute to mucronate, to 15.0 × 1.6 mm.

Glaucous stomatal band approx. as wide as or to 1.5x each green leaf margin. Seed Cones 6-9 mm, smaller than leaf length, dark blue when mature (2-3 years). Chromosome Number2n = 22 (Hall, Mukherjee and Crowley, 1979). Seeds 3 per cone. Pollen Shed spring. Fig. 12.

Common Name: Depressed juniper.

Distribution: common in mountains in United States and Canada (Fig. 11).

Habitat: rocky soil, rocky slopes and summits, sea level to 2800 m due to latitudinal range.

Status common and expanding into disturbed areas. Not threatened.

Uses: none known.

SHRUBS, similar to J. communis var. depressa, but differing in having curved to slightly curved leaves, with cross section concave and stomatal band 1.5-2 x width of green leaf margins, leaf blades free, 30° to 80° to the stem; Seed Cones about as long as leaves, ovoid, purple-blue when mature.

Gland on brown sheath elongated oval or if a long narrow gland, then with a rounded bottom end, immature Seed Cones globose, leaves most straight to slightly curved, not usually boat-shaped, free (not appressed to stem or leaf above on branchlet), usu. shrubs to 0.5 m tall with upturned to elevated branchlets, not on serpentine, but grows various habitats including granite, sandstone, alluvial, sand, and lava. Other specimens studied: Adams 10890, 10891, 10893, 10894 (BAYLU!). Fig. 13.

Juniperus communis var. kelleyi is common in the NW United States and BC, Canada. In British Columbia and Alaska, var. kelleyi and var. depressa appear to intergrade. Variety kelleyi has been treated as J. communis var. saxatilis Pall., but recent DNA sequencing found that var. saxatilis is restricted to the Eastern Hemisphere (Adams, 2013c).

Dioecious. Prostrate Shrubs. Trunk Bark cinnamon, exfoliating in wide strips or plates. Branches mostly prostrate on the ground. Leaves acicular, boat-shaped, curved, 7-10 mm, stomatal band 1.5 x as wide as green leaf margins. Seed Cones very glaucous, purplish blue, mature in 2-3 yrs, 9-13 mm, larger than leaf length. Seeds 1–3 per cone. Pollen Shed spring? Fig. 14.

Common Name: Large fruited common juniper.

Distribution: Newfoundland, Nova Scotia: Sable Island, Quebec: Magdalene Island, Canada. (Fig. 11).

Habitat: sand dunes, serpentine and limestone barrens; 0-500 m.

Status this is a very restricted taxon and can easily become threatened.

This is the most distinct variety of J. communis, especially in its seed cone size, it habitat on sand dunes, and DNA data, yet it appears to be of only recent (Pleistocene) origin (Adams et al., 2003).

Juniperus thurifera Spach, Ann. Sci. Nat. Bot., ser. 2, 16: 298. 1841, non L. 1753.

Juniperus mexicana Schiede ex Schltdl. & Cham., Linnaea 5: 77. 1830, non Spreng., 1826.

Juniperus foetida Spach, Hist. Nat. Veg. Phan. 11: 314. 1841.

Juniperus gigantea Roezl, in part, Cat. Graines Conif. Mexic. 8. 1857. Sabina gigantea (Roezl) Antoine, Cupress. Gatt.: 38 1857.

Juniperus deppeana Steud. var. pachyphlaea (Torr.) Martínez, Anales Inst. Biol. Univ. Nac. México 17(1): 53. 1946, (Holotype: United States: New Mexico, Zuni Mountains, Bigelow in 1853, NY!)

Juniperus pachyphlaea Torr., Pacific Railr. Rep.4(5): 142. 1857. Sabina pachyphlaea (Torr.) Antoine, Cupress. Gatt.: 39. 1857.

Sabina plochyderma Antoine, Cupress. Gatt.: 40. 1857. nom nud.

Adams, Zanoni and Hogge (1984), using leaf terpenoids examined the varieties of J. deppeana. They found that samples from Arizona (BA, SA) to be rather distinct from the other J. deppeana varieties (Fig. 15). However, additional research using DNA sequencing and fingerprinting (Adams et al., 2007), confirmed that there is only one variety in the southwestern United States (J. deppeana var. deppeana).

Dioecious. Trees 10-15(-30) m, with rounded crown. Trunk Bark in rectangular plates, (Fig. 16). Branches erect, often gray green or light green, branchlets (1 cm) exfoliating to reveal copper color. Leaves both decurrent (whip) and scale. Decurrent and scale leaf margins denticulate (20× magnification), whip and scale leaves usually with ruptured glands (clear, yellow or white exudate). Seed Cones globose, 8-15 mm across, fibrous to obscurely woody, maturing in the second year, reddish tan to dark reddish brown with glaucous bloom, (Fig. 17). Seeds 2-4 per cone, 6-9 mm long. Pollen Shed late winter - early spring.

Common NameS: Alligator bark juniper, Cedro, Cedro chins (Puebla), Sabino, Tascate (Chihuahua and Durango), Tlascal or Tlaxcal (Hidalgo), Huata, Agoziza (Sonora).

Habitat: rocky soils, slopes and mountains; 2000-2900 m.

Distribution: United States: Arizona, New Mexico, Texas. Northern Mexico (Fig. 18).

Status common, not threatened.

Uses: fence posts. Sprouts from cut stumps and is difficult to eradicate.

Adams et al. (2007) show (Fig. 15) that there is some differentiation between populations of var. deppeana from Arizona and New Mexico and those from the Chisos and Davis Mountains of Trans-Pecos Texas, but not sufficient to warrant formal recognition.

Dioecious. Trees 10-15 m, with rounded crown. Trunk Bark stem bark longitudinally furrowed into interconnected strips (Figs. 19, 20B). Branches terminal whip branches and larger branches somewhat flaccid. Leaves both decurrent (whip) and scale. Decurrent and scale-leaf margins denticulate (20× magnification). Seed Cones globose, 8-15 mm, fibrous to obscurely woody, maturing in the second year, reddish-tan when immature, then reddish- blue with very light bloom (glaucous) when mature. Seeds 5-6 per cone or 1(2) in Sonora (see discussion below), 6-9 mm long. Pollen Shed spring? Fig. 20.

Common Name: Sperry’s juniper.

Distribution: United States: Arizona Prescott National Forest, southwestern New Mexico at the Gila National Forest NM (Fig. 21), Texas, Davis Mountains, (Figs. 18, 22).

Habitat: rocky soils, slopes and mountains.

Uses: none known.

Status very rare, subject to burning.

Trees with furrowed bark and pendulous foliage are in northern Sonora and have only 1(2) seeds per cone. These are best referred to J. deppeana var. patoniana, but additional research is needed in this area. David Thornburg (pers. comm.) has recently found J. deppeana trees in northern Arizona that have furrowed bark. They do not seem to form a natural population, but occur as scattered individual trees among otherwise normal (quadrangular) barked trees. This suggests that only a few genes may be expressed to give the furrowed bark.

Creek park, 1845 m, 30° 43.437′N, 104° 08.255′W, 11 March 2005, R. P. Adams 10627 (Holotype: BAYLU!; Isotype: BAYLU!).

ADDITIONAL SPECIMEN EXAMINED: UnitedStates. Texas: Jeff Davis Co. summit of Brown Mountain, 2190 m, 11 March 2005, R. P. Adams 10629 (BAYLU).

Dioecious. Trees 4-5 m, with rounded crown. Trunk Bark stem bark in rectangular plates. Branches terminal whip branches elongated and very flaccid (Fig. 23). Leaves both decurrent (whip) and scale. Decurrent and scale-leaf margins denticulate (20× magnification). Seed Cones globose, 8-15 mm across, fibrous to obscurely woody, maturing in the second year, reddish tan when immature, then reddish blue with very light bloom (glaucous) when mature. Seeds 5-6 per cone or 1(2) in Sonora (see discussion below), 6-9 mm long. Pollen Shed spring? Fig. 23.

Distribution: United States. Texas: Davis Mountains, (Fig. 18).

Habitat: rocky soils, slopes and mountains.

Status: only two trees known.

Uses: none known.

Juniperus foetida var. flaccida (Schltdl.) Spach, Ann. Sci. Nat. Bot., sér. 2, 16: 300. 1841.

Juniperus gracilis Endl., Syn. Conif.: 31. 1847.

Juniperus gigantea Roezl Cat. Graines Conif. Mexic. 8. 1857. in part. Sabina gigantea (Roezl) Antoine, Cupress. Gatt.: 38, 1857.

Juniperus flaccida var. gigantea (Schltdl.) Gaussen, Trav. Lb. Forest. Toulouse 1(2/10): 117, 1968.

Dioecious. Trees to 12 m, trunk branching at 1-2 m. Trunk Bark cinnamon reddish brown or gray reddish brown, exfoliating in broad interlaced fibrous strips. Branches spreading and forming a globose crown. Ultimate branchlets drooping, flaccid. Leaves both decurrent (whip) and scale. Scale-leaves often appearing somewhat decurrent, 1.5-2 mm, opposite, narrowly ovate, acuminate. Whip- and scale-leaf margins appearing entire at 20× but with irregular teeth at 40×. Seed Cones spherical (4-)6-10(-13) seeded, tan-brown to brownish-purple with white glaucous, 9-20 mm in diameter maturing in 2 years? Seeds 5-6 mm long. Pollen Shed late winter-early spring. Fig. 24.

Common Name: Weeping juniper.

Distribution: Mexico, Big Bend National Park, Texas, United States (Fig. 25).

Habitat: rocky soils and slopes.

Status widespread in Mexico. The only population in the United States is in the Chisos Mountains, Big Bend National Park, Texas. Reproducing as evidenced by young and seedling plants in the area.

Uses: none known.

Dioecious, approx. 5% trees Monoecious (Vasek, 1966). TREES to 30 m. Trunk Bark brown. Branches erect to pendulous.

Leaves decurrent (whip) and scale-like, scale and whip-leaves with visible glands (Fig. 26). Seed Cones blue to blue black, with resinous pulp, maturing in 2 yrs, 5–9 mm long (avg. 7.6). Seeds 1-2(3) per cone (avg. 1.5). Pollen Shed spring. Fig. 26.

Common Name: Big western juniper, grand juniper.

Distribution: Sierra Nevada of California, western Nevada (Fig. 27).

Habitat: on dry rocky slopes in the Sierra Nevada of California; 1000-3000 m.

Status occurs in areas protected from fires. i.e. rocky with minimal combustible fuel, it is not threatened.

Uses: fence posts.

Adams et al. (2006), using both DNA sequence and fingerprinting data, showed that J. occidentalis var. australis is more closely related to J. osteosperma than to J. occidentalis. Based on these data, J. occidentalis var. australis was recognized as a distinct species, Juniperus grandis (Adams et al., 2006, Adams and Kauffmann, 2010). Juniperus grandis hybridizes with J. occidentalis and J. osteosperma (Adams, 2013a, 2013b) in northwestern Nevada and likely in populations north of Lake Tahoe, California.

Juniperus sabina Michx., Fl. Bor. Amer. 2: 246 (1803), non Juniperus sabina L. (1753)

Juniperus prostrata Pers., Syn. Pl. 2(2): 632 (1807), TYPE: ‘‘Hab. in Amer. austr.’’ probably Canada, A. Michaux s.n. (ex. herb. A. N. Desvaux). Juniperus sabina var. prostrata (Pers.) Loudon, Arbor. Frutic. Brit. 4: 2499, 1838. Juniperus virginiana L. var. prostrata (Pers.) Torr., Fl. New York 2: 235 (1843). Sabina prostrata (Pers.) Antoine, Cupress. Gatt.: 57 (1857)

Juniperus sabina Michx. var. procumbens Pursh, Fl. Amer. Sept. 2: 647 (1814)

Juniperus repens Nutt., Gen. N. Amer. Pl. 2: 245 (1818)

Juniperus sabina Michx. var. humilis Hook., in part, Fl. Bor. Amer. 2(10): 166 (1838)

Juniperus hudsonica Forbes, Pinet. Woburn.: 208 (1839)

Juniperus foetida Spach multicaulis Spach in part, Ann. Sci. Nat. Bot. sér. 2, 16: 295 (1841)

Juniperus horizontalis Moench fo. lobata O.W. Knight, Rhodora 9: 2010 (1907)

Juniperus horizontalis Moench fo. alpina (Loudon) Rehder, J. Arnold Arb. 6: 203 (1925)

Juniperus horizontalis Moench var. douglasii Rehder in L.H. Bailey, Stand. Cycl. Hort. 3: 1729 (1915)

Dioecious. Prostrate To Decumbent Shrubs. Trunk Bark brown, exfoliating in plates. Branches procumbent, forming large mats often several meters across. LEAVES decurrent (whip) and scale-like. Foliage green but turning reddish purple in winter. Leaf margins entire (20× and 40× magnifications). scale-leaf tips apiculate, mostly overlapping, both whip and scale leaves growing along the branchlets. Seed Cones 1-2(3) seeded, bluish black to bluish brown when ripe, borne on generally curved peduncles, mostly maturing in 2 years, 5-7 mm. (Fig. 28). Seeds 4-5 mm. Chromosome Number2n = 22 (Hall, Mukherjee and Crowley, 1979). Pollen Shed spring. Fig. 28.

Common NameS: Creeping juniper, prostrate juniper.

Distribution: Canada: all provinces. United States: Alaska, Montana, Wyoming, North Dakota, South Dakota, Nebraska, Minnesota, Iowa, Wisconsin, Illinois, Michigan, New York, Vermont, Massachusetts, Maine (Fig. 29).

Habitat: sand dunes, sandy and gravelly soils, prairies, slopes and along stream banks; sea level to 1000 m.

Status this taxon is common and reproducing. Not threatened.

Uses: none known.

Juniperus horizontalis hybridizes with both J. virginiana and J. scopulorum (Adams, 1983; Fassett, 1945a, b, c; Palma-Otal, et al., 1983). The J. horizontalis x J. scopulorum hybrid was named J. scopulorum var. patens Fassett (= X J. fassettii B. Boivin).

Dioecious. Prostrate Shrubs to small shrubs. Trunk Bark brown, exfoliating in wide strips or plates. Branches spreading. LEAVES acicular, curved, tips apiculate to mucronate, 5-7 mm x 1.6 mm.

Glaucous stomatal band 3-4 times as wide as each green leaf margin (Table 1). Seed Cones 6-7 mm, elongated-subglobose or ellipsoid, dark blue when mature (2-3 years). Seeds 1(2) per cone, (Fig. 30). Pollen Shed spring. Fig. 30.

Distribution: United States. Serpentine rock in northwestern California, on granite (Trinity Alps, California), lava talus slopes in Cascade Mountains in Oregon, and lava talus slopes, Olympic Mountains, Washington (Fig. 31).

Habitat: serpentine rock and lava talus slopes.

Status At present, the habitat (serpentine and lava talus slopes) seems conserved, so this species does not appear to be threatened nor endangered.

Uses: none known.

The type locality is on serpentine, but J. jackii also grows on high elevation lava at Mt. Hood, Oregon. Juniperus communis with short, curved leaves with a stomatal band about twice as wide as the green leaf margin, is found from northern California to Alaska. Recent analysis of nrDNA SNPs (Adams, 2008b) shows that the Siskiyou Mountains and Mt. Hood populations are somewhat different from the other populations. Those populations differ from J. communis also in having appressed, boat-shaped leaves and oblong cones. Juniperus jackii was recognized by Adams and Schwarzbach (2012) at the species level as it was found in a well supported clade using nrDNA and cpDNA.

Dioecious. Trees single stemmed to 15 m or more, pyramidal to round crown. Trunk Bark brown, exfoliating in thin strips. Branches foliage erect or occasionally lax, green but turning reddish-brown in the winter, twigs (3-5 mm diameter) with persistent dead scale leaves, bark on twigs (6-15 mm diameter) smooth, reddish brown. Leaves both decurrent (whip) and scale. Whip leaves growing only at branchlet tips (on mature trees), with an elliptical or elongated gland. Scale leaves overlapping by less than 1/5 length), tips obtuse. Scale-leaf margins entire (20× and 40× magnifications). Seed Cones globose to reniform, bluish black to bluish brown, maturing in 14 to 16 months, borne terminally, 6-8 mm in diameter, (1) 2 seeded. Seeds tan to brown, 2-4 mm long, commonly abnormally exserted due to insect damage. Pollen Shed March-April. Fig. 32.

Common Name: Seaside juniper.

Distribution: United States: Puget Sound and Strait of Georgia, Washington. Canada. British Columbia: Strait of Georgia. (Fig. 33). (See Adams et al., 2010 for notes on distribution on the Olympic Peninsula).

Habitat: near the seashore on southern and western exposed rock, on sand; on rock in the rain shadow of Mt. Olympia.

Status this taxon has very limited distribution and grows in areas of prime development, so it may become threatened.

Uses: none known.

Recent DNA sequencing shows J. maritima is in a well supported clade distinct from J. virginiana and J. scopulorum (Adams, 2014). This species is similar to J. scopulorum but differs in that the Seed Cones mature in 1 year (14-16 months), seeds are usually exserted from the cone, and the scale leaf tips are obtuse (Table 2).

Juniperus maritima is usually found in rocky areas, often within meters of the water. However, a population exists on coastal sand dunes near Cranberry Lake, Whidbey Island, WA. No other population has been found on sand, so that site may be atypical, and it has now been found on rocky areas in BC (Adams, 2015). Adams (2015) found evidence of hybridization and introgression between J. maritima and J. scopulorum.

J. occidentalis Hook. var. gymnocarpa Lemmon, Handb. W. Amer. Cone-bearers, ed. 3: 80. 1895.

Juniperus occidentalis Hook. fo. gymnocarpa (Lemmon) Rehder, J. Arnold Arbor. 7: 239. 1926.

Juniperus gymnocarpa (Lemmon) Cory, Rhodora 38: 184. 1936.

Dioecious. Shrub or small tree, 2-7(-12) m, usually with stems branching near the ground. Trunk Bark thin, gray to brown, exfoliating in thin strips revealing cinnamon color. Branches ascending to erect, with an ashy-white peeling bark. Leaves both decurrent (whip) and scale-like. Ultimate branchlets approx. 2/3 as wide as scale leaf length, square or six-sided but not terete. Whip- and scale-leaf margins denticulate (20× magnification). Scale leaves acute to acuminate. Whip-leaf gland ¾ as long as the leaf, adaxial (inner) leaf surface glaucous. Scale-leaves 1-3 mm, ovate, acute to acuminate, green. Scale-leaf tips free with the abaxial surface raised. Few (less than 1/5) whip-leaf glands ruptured and with a white crystalline exudate (visible without a lens). Seed Cones 6-8 mm diameter, soft and juicy pulp, globose to ovoid, reddish blue to bluish brown, white glaucous, 1(2-3) seeded, the hilum scar approx. 1/3 as long as seed, (Fig. 34). Seeds 4-5 mm long, sometimes exerted (as in Juniperus saltillensis M. T. Hall, Fig. 35). Pollen Shed late winter—early spring. Fig. 34.

Common Name: One-seeded juniper, cherry-stone juniper.

Distribution: United States: Arizona, Colorado, New Mexico, Oklahoma, Texas. (Fig. 36). Often reported from Mexico, but these plants should be referred to J. angosturana R. P. Adams or J. coahuilensis.

Habitat: common shrub in dry rocky soils and slopes; 1000-2300 m.

Uses: not rot resistant, not commonly used for fence posts.

Status this species is the dominant plant on millions of hectares in the state of New Mexico, United States. It is considered a weed in pastures by ranchers.

Hybridization between J. monosperma and J. pinchotii (Hall and Carr, 1968) is not supported using numerous chemical and morphological characters (Adams, 1972; 1975). In addition their Pollen Shedding times do not overlap (J. monosperma in March - April, J. pinchotii in September - October). Hybridization with J. coahuilensis, that sheds its pollen in March-April, does appear possible in southwestern New Mexico. The distribution of J. monosperma is shown in Fig. 36.

Juniperus andina Nutt., N. Amer. Sylva 3: 95, t.110. 1849.

Chamaecyparis boursieri Decne., Bull. Soc. Bot. France 1: 70. 1854.

Juniperus pseudocupressus Dieck, Neuheit.Off. Nat.-Arb. Zoschen 1899: 8. 1899.

Juniperus californica Carrière var. siskiyouensis L.F. Henderson, Rhodora 33: 203. 1931.

Monoecious/Dioecious approx. 50% of the plants are monoecious (Vasek, 1966). Trees to 20 m. Trunk Bark red brown. Branches ascending. Leaves decurrent (whip) and scale-like, both kinds with visible glands. Seed Cones blue to blue-black, with resinous pulp, maturing in 2 years, 7-10 mm long (avg. 8.3). Seeds 1-2(3) per cone (1.6 avg.). Pollen Shed late spring. Fig. 37.

Common Name: Western juniper, Sierra juniper.

Habitat: dry rocky foothill and mountain slopes; (near sea level) to 1500-3000 m Map: Vasek, 1966.

Uses: fence posts (but not very rot resistant).

Distribution: United States. Sierra Nevada of northern California, Idaho, Nevada, Oregon and Washington (Fig. 38).

Status common and reproducing. Considered a weed on pasture lands in Oregon.

Vasek (1966) reported hybridization with J. osteosperma in northwestern Nevada.

Terry et al. (2000) confirmed hybridization between J. occidentalis and J. osteosperma using chloroplast and nuclear DNA markers. Adams et al. (2006), using both DNA sequence and fingerprinting data, clearly showed J. occidentalis var. australis to be more closely related to J. osteosperma than J. occidentalis. Based on these data, Juniperus occidentalis var. australis was recognized as the distinct species, J. grandis (Adams et al., 2006, Adams and Kauffmann, 2010). Juniperus occidentalis hybridizes with J. osteos pe rm a, Adams, 2013a, 2013b) i n northwestern Nevada and it likely hybridizes with J. grandis in populations north of Lake Tahoe, California.

Similar to Juniperus occidentalis but differing in habit, being a shrub with compact foliage (Fig. 39). The typical variety, with a strong central axis and pyramidal crown, grows on a nearby hillside, whereas fo. corbetii grows along a dry wash on a mix of lava and sand. No female cones were found in this population.

Juniperus osteosperma (Torr.) Little, Leafl. Western Bot. 5: 125, 1948. Juniperus tetragona Schltdl. var. osteosperma Torr., Pacif. Railr. Rep. 4(5): 141, 1857. Sabina osteosperma (Torr.) Antoine, Cupress. Gatt. 51. 1857. Juniperus californica Carrière subsp. osteosperma (Torr.) A. E. Murray, Kalmia 12: 21. 1982. TYPE: Arizona, Coconino Co., Bill Williams Mt., J. M. Bigelow s.n. (Lectotype: NY! designated by Little p. 127, 1948).

J. californica var. utahense Vasey, Cat. For. Trees U.S. 37. 1876.

Juniperus californica var. utahensis Engelm., Trans. Acad. Sci. St. Louis 3: 588. 1878. Juniperus utahensis (Engelm.) Lemmon, Bienn. Rep. Calif. State Board Forest. 3: 183. 1890. Sabina utahensis (Engelm.) Rydb., Bull. Torrey Bot. Club 32: 598. 1905.

Juniperus occidentalis Hook. var. utahensis Kent, Veitch’s Man. Conif.: 289. 1881.

Juniperus knightii A. Nelson, Bot. Gaz. 25: 198. 1898. Juniperus monosperma (Engelm.) var. knightii (A. Nelson) Lemmon, Cone-bear. Trees Pacif. Slope, ed. 4: 114. .1900. Sabina knightii (A. Nelson) Rydb., Bull. Torrey Bot. Club 32: 598. 1905.

Juniperus utahensis (Engelm.) Lemmon var. cosnino Lemmon, Sierra Club Bull. 4: 122, pl. 62. 1902.

Juniperus megalocarpa Sudw., Forest & Irrig. 13: 307. 1907. Sabina megalocarpa (Sudw.) Cockerell, Muhlenbergia 3: 143. 1908. Juniperus utahensis (Engelm.) Lemmon var. megalocarpa (Sudw.) Sarg., Bot. Gaz. 67: 208. 1919.

Monoecious Or Rarely Dioecious (10%). Shrubs multi- (seldom one) stemmed, shrub or tree, 3-6(-12) m with round crown. Trunk Bark exfoliating in thin gray brown strips. Bark on twigs (5-10 mm diameter) brown or gray, not exfoliating in scales or flakes. Branches erect. Leaves decurrent (whip) and scale-like, foliage light yellow green. Whip- and scale-leaf margins denticulate (20× magnification). Leaf glands not conspicuous (embedded in the leaf, therefore not visible). Seed Cones fibrous, bluish brown, with white glaucous, often almost tan beneath the glaucous bloom, (6-)8-9(-13) mm diameter, maturing in 1-2 years. Seeds 1(2), avg.1.07 per cone, 4-5 mm long. Pollen Shed spring. Fig. 40.

Common Name: Utah juniper.

Distribution: United States: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming (Fig. 41).

Habitat: dry, rocky soil and slopes; 1300-2600 m.

Status abundant in Utah and adjacent states. Considered a weed in ranch lands.

Uses: none known, not rot resistant. Trunks of living trees often with rotted heartwood.

Juniperus osteosperma is the dominant juniper of Utah. Terry et al. (2000) reported hybridization between populations of J. occidentalis and J. osteosperma in northwestern Nevada using cp and nuclear DNA markers. Adams (2013a, 2013b) using leaf terpenes confirmed that J. osteosperma hybridizes with J. occidentalis in northwestern Nevada. It appears to hybridize with J. monosperma in northwestern New Mexico based on morphological intermediacy between the two species (pers. obs.).

Dioecious. Trees with broad, bushy rounded or irregularly open crown, to 15 m, with a single trunk branching at 1-3 m or occasionally branching at the base. Trunk Bark exfoliating in thin brown strips. Branches brown but usually with a greywhite fungus. LEAVES both whip and scale-like. Whip leaves with a raised, oval or elliptical glands (not obvious on scale leaves, but round on scale leaves). Whip- and scale-leaf margins denticulate (20× magnification). Seed Cones ovoid to subglobose, maturing in one year, dark blue and glaucous, (5)6(-8) mm, seeds (1)2 (avg. 1.7) per cone. Seeds 4-6 mm long. 2n = 22. Pollen Shed Dec-Feb. Fig. 3.

Additional Specimens Examined: Mexico. Coahuila, Adams 1066-1076. United States. Texas: Crockett Co., 5 km west of Ozona, 6 Dec 1994, R. P. Adams 7464, 7465, 7466, 7467 (BAYLU); Comal Co. Jct. Tex 46 and Loop 337 in New Braunfels, 16 Mar 2007, Adams 11314, 11315, 11316 (BAYLU), 40 m southwest of Jct. Cedar Elm St. and Madeline St. on Madeline St., New Braunfels, 16 Mar 2007, Adams 11309, 11310, 11311 (BAYLU).

Distribution: United States: Texas. Northern Mexico (Fig. 4).

Habitat: Limestone glades and bluffs, 150-600 m.

Status abundant on limestone in central/west Texas. The range is expanding, and it is regarded as a weed in Texas.

Uses: fence posts.

Juniperus ovata is morphologically similar to J. ashei, but instead of having hemispherical glands, the glands are oval to elliptical on the whip-leaves. Juniperus ovata also has smaller cones, and more seeds per cone (∼2) than J. ashei. The whip-leaf glands are illustrated in Fig. 42. Notice hemispherical glands on J. ashei and the raised, oval to elongated glands on J. ovata. It should be noted that a few nearly hemispherical glands are present on whip-leaves of J. ovata. Gland morphology is informative, as this character can be used to distinguish ovata from ashei, yet exclude other nearby juniper species such as J. monosperma, J. pinchotii and J. coahuilensis which do not have raised hemispherical glands.

Results from DNA sequencing (Adams and Schwarzbach, 2013a,b) found Juniperus ovata is in a clade with J. saltillensis and J. zanonii R. P. Adams, and is not as closely related to J. ashei as previously thought.

The distribution of the two taxa shows (Fig. 4) areas of possible sympatry are in west Texas and around New Braunfels in central Texas. Additional field collections are needed to define better their distributions in these areas (Adams 2008a, Adams and Baker, 2007).

Juniperus texensis Melle, Phytologia 4: 26 (1952)

Dioecious. SHRUBS to small shrubby tree, 1-6 m, usually multi- stemmed at the base and forming broad shrubs. Trunk Bark thin, ashy gray, exfoliating in long strips. Branches stiff, erect or spreading, the bark in long, narrow scales. Leaves both decurrent (whip) and scale-like. Whip- and scale-leaf margins denticulate (20×), leaves yellow green. Adaxial leaf surface not glaucous. Many glands ruptured and with a white, crystalline (mostly camphor) exudate, both whip- and scale-leaf glands elliptical to elongate. Seed Cones copper to copper-red, not glaucous, globose to ovoid, 6-8(-10) mm; soft and juicy, sweet pulp, 1(2) seeded. Seeds 4-5 mm long, the hilum scar approx. ½ as long as the seed. Pollen Shed fall. Fig. 42.

Common NameS: Copper berry juniper, Pinchot juniper, red-berry juniper.

Distribution: United States. New Mexico, Oklahoma, Texas. Northeastern Mexico (Fig. 43). An isolated very small population has recently been discovered in Duval Co., TX (Adams and Schwarzbach, 2011).

Habitat: 300-1000(-1700) m; gravelly soils on rolling hills and ravines, limestone, gypsum.

Status this species is abundant in its range and is an invasive weed that invades degraded grasslands. It has greatly increased in areas that are not subjected to periodic burning.

Uses: occasionally used as fence posts, but it is not rot resistant.

The species forms hybrids with J. coahuilensis (see above). No hybridization with J. ashei has been found (see discussion above) nor has hybridization with J. monosperma (see above) been documented, at least by terpenoid analyses. Hall et al. 1961 reported hybridization between J. ashei and J. pinchotii, but this seems unlikely because J. pinchotii sheds pollen in Sept-Oct. and J. ashei sheds pollen in Dec-Feb.

Sabina scopulorum (Sarg.) Rydb., Bull. Torrey Bot. Club 32: 598. 1905.

Juniperus virginiana L. subsp. scopulorum (Sarg.) A. E. Murray, Kalmia 13: 8. 1983.

Juniperus excelsa Pursh, Fl. Amer. Sept. 2: 647. 1814, non M.-Bieb. (1800)

Juniperus virginiana L. var. montana Vasey, Cat. For. Trees U.S. 37. 1876.

Juniperus occidentalis Hook. var. pleiosperma Engelm., Trans. Acad. Sci. St. Louis 3: 590. 1878.

Juniperus scopulorum var. patens Fassett, Bull. Torrey Bot. Club 72: 46. 1945. [= X fassettii Boivin (horizontalis x scopulorum) ]

Juniperus scopulorum Sarg. var. columnaris Fassett, Bull. Torrey Bot. Club 72: 482. 1945. Juniperus scopulorum Sarg. f. columnaris (Fassett) Rehder, Biblio. Cult. Trees: 63. 1949. Juniperus scopulorum var. columnaris Fassett (environmentally induced by gases from burning coal, see Adams, 1982)

Juniperus fassettii B. Boivin, Naturaliste Canad. 93: 372. 1966.

Dioecious. Trees single (rarely multi-) stemmed tree to 20 m, pyramidal to occasionally round crowns. Twigs (3-5 mm diameter) with smooth bark, twigs (6-15 mm diameter) with bark exfoliating in plates, reddish copper beneath. Trunk Bark brown, exfoliating in thin strips. Foliage light to dark green but often blue and blue gray due to glaucousness. Branches erect to occasionally pendulous at the tips. Leaves both decurrent (whip) and scale. Whip-leaves growing only at branchlet tips (on mature trees). Scale-leaves not overlapping, or, if so, then not by more than 1/5 the length, obtuse to acute, margins entire at 20× magnification (and 40× magnification). Seed Cones maturing in 2 years, globose to 2-lobed, appearing light blue when with heavy glaucous coating, but dark blue black beneath glaucous (when mature). [Note: cones may appear tan beneath the glaucous cover when immature], 6-9 mm, borne on mostly straight peduncles. Seeds (1)2(3) per cone, 4-5 mm long. Chromosome Number2n = 22 (Hall, Mukherjee and Crowley, 1973). Pollen Shed March-April. Fig. 44.

Common Name: Rocky mountain juniper.

Distribution: Canada: Alberta, British Columbia. USA: Arizona, Colorado, Idaho, Montana, Nebraska, North Dakota, New Mexico, Nevada, Oregon, South Dakota, Texas, Utah, Washington, Wyoming. Northern Mexico (Fig. 45).

Habitat: rocky soils, and slopes, eroded hillsides, sea level (Vancouver Isl., Puget Sound), otherwise 1200-2700 m.

Status abundant and increasing, considered a weed in rangelands.

Uses: fence posts.

Juniperus scopulorum hybridizes with its eastern sibling species, J. virginiana in the zones of contact in the Missouri River Basin (Comer, Adams and Van Haverbeke, 1982; Flake, Urbatsch and Turner, 1978; Van Haverbeke, 1968). Relictual hybridization with J. virginiana is present in Palo Duro Canyon in the Texas Panhandle (Adams, 1983). The species also hybridizes with J. horizontalis (see J. horizontalis, above).

Juniperus caroliana Mill., Gard. Dict., ed. 8: Juniperus No. 4. 1768.

Juniperus. arborescens Moench, Methodus: 699. 1794.

Juniperus caroliniana Du Roi, Harbk. Baumz., ed 2, 1: 497. 1795.

Juniperus hermannii Spreng., Syst. Veg. 3: 908. 1826.

Juniperus virginiana L. var. vulgaris Endl., Syn. Conif.: 28. 1847.

Juniperus virginiana L. var. crebra Fernald & Griscom, Rhodora 37: 133, t. 332. 1935. Juniperus virginiana L. subsp. crebra (Fernald & Griscom) E. Murray, Kalmia 12: 21 (1982)

Juniperus virginiana L. var. ambigens Fassett; (=X Ambigens, virginiana x horizontalis) Bull. Torrey Bot. Club 72: 380. 1945.

In the present treatment, two varieties are recognized. However, var. virginiana may be divided into pyramidal (var. virginiana) and strict (var. crebra) growth habits. Research is currently being conducted to determine if var. crebra merits recognition.

Juniperus barbadensis C. Mohr, non Juniperus barbadensis L.

Dioecious. Trees small tree to 10 m, with a flattened crown, pyramidal when young and protected or crowded. Trunk Bark cinnamon-reddish, exfoliating in narrow strips. Branches spreading to pendulous, ultimate twigs terete or 4-angled. Leaves both decurrent (whip) and scale. Scale-leaves bluntly obtuse to acute. Whip- and scale-leaf margins entire (20× and 40×). Pollen cones 4-5 mm. Seed Cones maturing in 1 year, blue, glaucous, resinous, ovoid 4-5 mm diameter. Seeds tan to chestnut brown, 1.5-3 mm long. Pollen Shed late winter - early spring. Fig. 46.

Common NameS: Southern red cedar, coastal red cedar.

Distribution: United States: along the coast, North Carolina South Carolina,

Georgia, western Florida, and Alabama (Fig. 47).

Habitat: coastal fore-dunes, coastal river sand banks, sea level to 15 m.

Status this southern variety of J. virginiana appears to be restricted to coastal fore-dunes and differs little in morphology or leaf terpenoids from the upland J. virginiana var virginiana (Adams, 1986). Both of these taxa are distinct from the Caribbean junipers (J. barbadensis var. lucayana Britt., Bahamas, Jamaica, Cuba; J. bermudiana L., Bermuda, see Adams, Zanoni and Hogge, 1984). There appears to be some intergradation of characters between J. virginiana var. virginiana and this variety in Georgia (Adams, 1986).

Uses: no known uses.

Dioecious. Trees single stemmed to 30 m, pyramidal to strict. Trunk Bark brown, exfoliating in thin strips. Branches foliage erect or occasionally lax, green but turning reddish-brown in the winter, twigs (3-5 mm diameter) with persistent dead scale leaves, bark on twigs (6-15 mm diameter) not exfoliating in plates, if so brownish beneath. Leaves both decurrent (whip) and scale. Whip-leaves growing only at branchlet tips (on mature trees), with an elliptical or elongated gland. Scale leaves overlapping (more than ¼ length). Scale-leaf margins entire (20× and 40× magnifications). Seed Cones blue-black to brownish blue, maturing in 1 year, borne terminally, 3-6(7) mm in diameter, 1-2(3) seeded. Seeds tan to brown, 2-4 mm long. Chromosome Number2n = 22, 3n = 33 (Hall, Mukherjee and Crowley, 1979). Pollen Shed March-April. Fig. 48.

Common NameS: Red cedar, Virginia cedar, eastern red cedar.

Distribution: Canada: Ontario, Quebec. United States: all states except: Alaska, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, North Dakota, Oregon, Utah, Washington, Wyoming, (Fig. 49).

Habitat: upland or low woods, old fields, glades, fence rows and river swamps, from near sea level to 1400 m.

Status Perhaps the most aggressive, weedy juniper in the world. It is spread by birds and invades abandoned fields and roadsides in the eastern United States from the Atlantic Ocean to the Edwards Plateau in central Texas and into the central Great Plains.

Uses: production of eastern red cedar wood oil, furniture, fence posts, widely cultivated for landscaping.

Juniperus virginiana hybridizes with J. horizontalis (see J. horizontalis) and J. scopulorum (see J. scopulorum). Earlier reports of hybridization between J. ashei and J. virginiana (Hall, 1952) were not supported in subsequent studies using leaf terpenoids (Adams, 1977; Flake et al., 1969).

Eastern Red Cedar is an aggressive, weedy species. Juniperus virginiana var. virginiana (and most junipers) are disseminated by birds and a typical pattern in the USA is the’fence row junipers’ where birds have dropped the seeds while sitting on the fence wire. It also invades disturbed sites as well as old fields. Juniperus virginiana var. virginiana is the most weedy juniper known, in that it can invade tall (0.5 m tall) grass prairie. The control of Juniperus is a major problem in the United States. Interestingly, the junipers of the eastern hemisphere are seldom weeds. Of course, the spread of juniper in the eastern hemisphere is often limited by goat grazing. In contrast, goat grazing is a relatively modern phenomenon in the western hemisphere and little practiced in the United States. Goat grazing has been reported to completely remove young junipers in central and west Texas (Taylor and Fhlendorf, 2003; Taylor et al., 2005; Allred et al., 2012).