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Juniperus
Linnaeus 1753
Common NamesJuniper, cedar, redcedar; cedro, sabino [Spanish] (1).Taxonomic notesThe genus is characterised by fleshy cones with hard-shelled seeds, adaptations to avian seed dispersal; apart from this, all characters common to all of its species can also be found in other closely allied genera of Cupressaceae, notably Cupressus, Platycladus and Microbiota . About 50 species; species delimitations, particularly in central Asia, are as yet very poorly researched and this number is subject to revision (most likely downward, in view of the plethora of published names of uncertain status).The genus is usually divided into three distinct sections or subgenera, sometimes treated as genera; descriptions of which are provided below:
Sect. Caryocedrus is close to sect. Juniperus (several distinct characters shared), and of obvious monophyletic origin with it; future generic recognition under Arceuthos is highly unlikely. DescriptionEvergreen shrubs or trees. Branchlets terete, 4-6 angled, variously oriented, but not in flattened sprays (except in J. flaccida ). Leaves in decussate (alternating) opposite pairs in 4 ranks or in alternating whorls of 3 in 6 ranks, rarely in whorls of 4 in 8 ranks. Adult leaves closely appressed to divergent, scalelike to subulate, free portion nil to 25 mm (to 32 mm recorded in J. formosana ); abaxial gland visible or not, elongate to hemispheric ( J. ashei ), sometimes exuding white crystalline deposit. Pollen cones with 3-7 pairs or trios of sporophylls, each sporophyll with 2-8 pollen sacs. Seed cones maturing in 1 or 2 years, globose to ovoid and berrylike, 3-20 mm (to 25 mm in J. drupacea ), remaining closed, often glaucous; scales persistent, 1-5 pairs or whorls of three, peltate or valvate, tightly coalesced and fused together, thick and fleshy or fibrous to obscurely woody; some sweet (e.g. J. deppeana ), many bitter and/or resinous. Seeds 1-3 per scale, round to faceted, wingless; cotyledons 2-6. Seed dispersal by frugivorous birds, which swallow the cones whole, digest the fleshy scales and pass the hard-shelled seeds undamaged through the gut; the bitter taste of many species may be related to discouraging mammalian predators of the seeds. x = 11.
About 7-9 species; type J. communis L. The section is divisible into two subsections, a northern group with blue-black mature cones and one broad leaf stomatal band ( J. communis and allies; 2-4 spp.), and a southern group with orange-red mature cones and two narrow leaf stomatal bands separated by the midrib ( J. oxycedrus and allies; 5 spp.).
Source: (1, 6). RangePrimarily Northern Hemisphere, one species ( J. procera ) in E Africa to 18°S. In many semiarid regions, such as through much of the western USA, northern Mexico and central & southwest Asia, it provides the dominant forest cover on large sections of the landscape. Sect. Juniperus is primarily Eurasian, with one species ( J. communis ) holarctic, the only member of the section in N. America and by far the most widespread single conifer species. Sect. Caryocedrus is a local endemic in SW Asia and SE Europe. Sect. Sabina occupies most of the range of the genus, except for Eurasia north of 50°N in Europe and 60°N in Asia.Big TreeThe limited data I have found suggest it is J. occidentalis . Tallest may be J. drupacea , measured to c .40 m tall in Turkey (H. Karaca).OldestAgain, there are no data for most species, but a ages of about 2000 years has been established for J. scopulorum .DendrochronologyA variety of species have proven useful, delivering dendroclimatic records of up to 1000 years and providing archeological data in the American southwest. However, some species lack circuit uniformity or have a large fraction of missing rings.EthnobotanyNumerous cultivars of Juniperus species are widely used for landscaping (1). Because the genus is widely distributed in semiarid regions (it grows particularly well on calcareous soils) and some are not particularly palatable to domestic goats, it often affords the only tree of size on the landscape, thus providing an important source of wood for construction, fuel and other domestic uses. The wood is fragrant, usually reddish or reddish-brown, easily worked, very durable, and rarely injured by insects (5). Its resistance to decay makes it particularly useful for fenceposts and other ground-contact applications. However, it seldom achieves the size or straight grain needed in lumber. Many native peoples have used the aromatic foliage and resins for medicinal or spiritual purposes."An essential oil is obtained by distillation from wood and leaves. That from the wood is often used for perfumery, sometimes in medicine. Oil from the leaves and shoots is also used in medicine. They have powerful diuretic properties and stock should not be allowed to eat branches" (5).Wood and/or foliage are often burned for incense in Buddhist temples. Cones of J. communis are used for flavouring gin. ObservationsSee the respective species. Please inform me if you know of any arboreta with exceptional Juniperus collections.RemarksJuniperus is an old Latin name used by Virgil and Pliny (2)."Mutants, or "sports," affecting plant habit and foliage are present in all species and are likely related to single-gene mutations. Many have been given formal names or incorrectly ascribed to hybridization. Gymnocarpy (bare seeds protruding from the cone), caused by insect larvae (4), is occasionally found in most junipers, particularly in the southwestern United States. Specimens with such aberrations may be almost impossible to identify without chemical data" (1). Citations(1) Adams, Robert P. in Flora of North America online .(2) Weber 1987 . (3) Cheng & Fu 1987 . (4) Zanoni 1978 . (5) Dallimore & Jackson 1967 . (6) M.P. Frankis, personal observations, text prepared for this page.
See also:
This page co-edited with M.P. Frankis, Mar-1999. |
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This page is from the Gymnosperm Database
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