Juniperus communis

Status UK Biodiversity Action Plan Priority . IUCN Threat category: Least concern (2005).

Taxonomy Pinopsida: Male cones Scientific name: Juniperus communis L. Common names: , Merywen

Juniperus L. is a diverse genus of c. 75-80 species, the second largest genus of after Pinus.

Juniperus communis, the only native species in Britain, is a variable species throughout its range and there is some disagreement about how best to treat it taxonomically. Three weakly defined subspecies with intermediates are currently reported for the British Berries (purplish-black Isles (Stace 1997). when ripe)

An erect or spreading bush to 7(-10) m tall; leaves 8-20 mm x c. 1mm, loosely and irregularly spaced, with a greyish-white stomatal band, apex gradually tapered to a long point so that shoots are prickly to Figure 1. Juniperus communis L. (from J. E. Smith & J. Sowerby touch; fruits globose. (1852). English Botany. London) Subsp. communis has largely eliminated it on grouse moors, and the Low compact ; leaves mostly 8-20 x 1.3-2mm, scrub communities in which it regenerates have closely and regularly spaced with a pure white declined severely due to grazing, burning, succession stomatal band, apex gradually tapered to a long to woodland and afforestation. Regeneration is point so that shoots are prickly to the touch (fruit inhibited by continuous grazing. not seen). Subsp. hemisphaerica (J. & C. Presl) Nyman Subsp. communis is very local but often common throughout Britain and Ireland (Preston et al. 2002). It A procumbent bush; leaves 4-10 x c.1.5mm, apex more occurs on both limestone and acid soils and can form a suddenly contracted to a shorter sometimes blunt distinctive shrub community. Regeneration from seed point so that shoots are scarcely prickly to touch; is poor as reproduction from seed is dependant on fruit longer than broad. disturbance and/or a sudden cessation of grazing. Subsp. nana (Hook.) Syme Subsp. hemisphaerica is confined to the Lizard, West Biology & Distribution Cornwall where it grows on broken rocky slopes over Juniperus communis is a dioecious, evergreen serpentine rocks (Updated from Preston et al. 2002). found on basic and acidic soils in a wide range of Recent genetic work indicates a population reported habitats, including lower calcareous grassland, chalk from Pembrokeshire is subsp. communis. IUCN Threat downland, limestone pavement, heather moorland, category: Critically endangered (2005). maritime cliff and slope, oceanic heaths, rocky slopes and in birch, oak and pine . It has been declining Subsp. nana occurs mostly in upland areas in north in southern Britain for many years; burning Wales, northern England, Scotland and western Ireland (Preston et al. 2002). It is found in a variety References of coastal and montane dwarf-shrub heaths, often Clifton, S. J., Ward, L. K. & Ranner, D. S. (1996). The subject to severe wind-pruning, and on rock ledges status of Juniper, Juniperus communis L. in north- and blanket bogs. east England. Biological Conservation 79: 67-77. Evans, S. (2002/2003). The prostrate of In Wales it occurs on rocks and moorland mostly in Pembrokeshire. Botanical Society of the British Isles upland areas. Welsh Bulletin 71: 13-17, and 72: 15. Preston, C.D., Pearman, D. A. & Dines, T. D. eds. Identification & Field survey (2002). New Atlas of the British & Irish flora. From all the other conifers and trees in Britain, Oxford University Press, Oxford. both native and introduced, J. communis is easily Stace, C. A. (1997). New Flora of the British Isles. 2nd distinguished by having leaves all needle-like up to edition. Cambridge University Press, 2 cm long in whorls of 3 around the stem. The leaves Cambridge. also have a broad single white stripe (stomatal band) Ward, L. K. (1973). The conservation of Juniper, 1. on the upper side. Present status of Juniper in southern England. Journal of Applied Ecology 10: 165-188. Key characters Ward, L. K. (1981). The demography, fauna and Shrub to 7m tall with habit varying from procumbent conservation of Juniperus communis in Britain. in to erect and narrow, rarely a small tree to 10m. Leaves The Biological Aspects of Rare Conservation. linear to linear-oblong, 4-20 mm long with a spiny BSBI Conference Report 17: 319-329. point, held spreading outwards in whorls of three, Ward, L. K. (1982). The conservation of Juniper: with a single broad white band on the upper side. longevity and old age. Journal of Applied Ecology Female cones 5-10 mm, becoming fleshy in the second 19: 917-928. or third year and turning a blue-black when ripe. A full species dossier is available on the Plantlife website (www.plantlife.org.uk)

Additional photographs are available on the ARKive website (http://www.arkive.org/species).