Summary1. This account reviews information on all aspects of the biology of Juniperus communis that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles : distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history and conservation. 2. Juniperus communis (juniper) is an evergreen dioecious gymnosperm shrub with two main population centres in Britain, one on chalk downlands of southern England and the other in northern England and Scotland. British populations are divided into two main subspecies although there is overlap in genetic and morphological features. Subspecies communis varies from a spreading shrub to an erect tree characteristic of calcareous soils in southern England, various soils in the Scottish highlands, while ssp. nana is a small procumbent shrub, restricted to well-drained bogs and, more usually, rocky outcrops, generally as a minor component of upland heaths and montane scrub. Both subspecies are drought and frost tolerant, although sensitive to fire. A third subspecies, hemisphaerica , primarily found in mountains of southern Europe has two small populations on maritime cliffs in the UK. 3. Although not very palatable, J. communis is grazed by small and large mammals when food is short, particularly in winter. Its low palatability is derived from oils found in the needles, cones and wood, dominated by monoterpenes. These have been extensively used in folklore medicine and to flavour alcoholic drinks, and are being investigated for new medicinal uses. 4. Juniperus communis ssp. communis is a characteristic light-demanding invader of pasture but has declined due to agricultural expansion, erosion, overgrazing, fire and poor regeneration, such that it is now rare and threatened across lowland/southern Europe. Although susceptible to overgrazing, some grazing can be beneficial to create the open sward necessary for seedling establishment. Other limits to regeneration are: progressively ageing stands in which male plants predominate; increasing fragmentation of stands that reduces pollination efficacy; and high seed dormancy with consequent variable germinability.Key-words : climatic limitation, communities, conservation, ecophysiology, geographical and altitudinal distribution, germination, herbivory, mycorrhiza, parasites and diseases, reproductive biology, soilsJournal of Ecology (2007) 95 , 1404-1440 doi: 10.1111/j.1365-2745.2007.01308.x *Abbreviated references are used for many standard works: see Journal of Ecology (1975), 63 , 335 -344. Nomenclature of vascular plants follows Flora Europaea and, where different, Stace (1997). †Author to whom correspondence should be addressed: P. A. Thomas. E-mail: p.a.thomas@biol.keele.ac.uk. Pinopsida (Coniferae), Cupressaceae. The junipers are a taxonomically difficult group, composed of about 68-80 s...

Summary1. This account presents information on all aspects of the biology of Euonymus europaeus that are relevant to understand its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation. 2. Euonymus europaeus (Spindle tree) is a native gynodioecious deciduous shrub whose distribution is mostly associated with fertile soil at higher pH values. It is frequently found in hedgerows and woodland edges but also in woodland as an understorey shrub, often with Fraxinus excelsior, Acer campestre and Quercus species, and in open scrub over limestone with Cornus sanguinea. Its seed is widely dispersed by birds and rodents. 3. Euonymus europaeus is winter hardy and shade tolerant and, when young, its green shoots with stomata fix c. 15% of its CO 2 . The aril is eaten by a range of animals but the seeds are poisonous and the whole plant contains compounds of medicinal and veterinary value. 4. Euonymus europaeus acts as the winter host to two important crop pests: the black bean aphid (Aphis fabae) which feeds on field beans (Vicia faba) and sugar beet (Beta vulgaris), and the peach potato aphid ⁄ green peach aphid (Myzus persicae) a widespread pest of a large number of crops. Despite removal of E. europaeus from hedgerows and woodlands in the past, its present populations appear stable.Key-words: climatic limitation, communities, conservation, ecophysiology, geographical and altitudinal distribution, germination, herbivory, mycorrhiza, parasites and diseases, reproductive biology, soils Spindle or Spindle tree. Celastraceae. Euonymus europaeus L. (Euonymus vulgaris Mill.) is a. much-branched, non-spiny, deciduous, glabrous or minutely hairy shrub or small tree to 2-6(8) m. Bark grey, smooth. Buds small (2-4 mm), ovoid, greenish, acute, bud scales with a dark edge. Twigs green, ±4-angled, branches at almost right angles to shoot. Leaves opposite, green, often turning red in autumn, 3-8(13) cm long, c. 1.5-4-cm wide, elliptical or oblong-lanceolate to ovate-lanceolate, acute or acuminate, entire or crenate-serrulate, base cuneate; petiole 6-12 mm, grooved along the top. Flowers in 3-to 10-flowered, dichotomous axillary, pedunculate cymes, glabrous, 8-10 mm diameter, usually four-merous, parts borne around a broad green nectary, frequently called hermaphroditic but in reality gynodioecious. Petals thicker than the sepals, greenish, oblong, widely separated, the ventral surface papillate. Ovary partially inferior, placentation axile, the stigmatic lobes opening like a mouth as they become receptive. Stamens partially fused with the ovary wall. Fruits a deep pink or (very rarely) white fleshy capsule, normally four-locular (with two ovules per loculus), 8-15 mm across, opening to show bright orange arils which completely (or almost so...

<abstract> <p>Callogenesis and embryogenesis are integral parts of many tissue culture procedures for genetic manipulation in rice. However, the efficiency of both processes is largely dependent on the media constituent especially the plant growth regulators (PGRs) due to the genotype-dependent nature of <italic>in vitro</italic> culture protocols. Therefore, this study investigates the effect of two PGRs; 2, 4-dichlorophenoxyacetic acid (2, 4-D) and kinetin (Kin) on callus growth and somatic embryogenesis of an important Malaysian rice cultivar (<italic>Oryza sativa</italic> L. cv. MARDI Siraj 297). Mature rice seeds explants were inoculated in Murashige &amp; Skoog (MS) medium supplemented with different combinations of 2, 4-D (0 to 3.5 mg/L) and Kin (0 to 0.5 mg/L) to induce callogenesis. Parameters for callus growth such as fresh weight (FW), callus induction frequency (CIF), embryogenic callus frequency (ECF), regeneration frequency (RF), number of plantlets per callus (PPC), callus texture and callus color were observed after 35 days of inoculation. The results show that the maximum callus growth was achieved in MS medium supplemented with combination of 2.0 mg/L 2, 4-D and 0.2 mg/L Kin, represented by the highest FW (211 mg), CIF (95%), ECF (90%), RF (100%) and PPC (22 plantlets); along with friable callus texture. Low concentration of 2, 4-D (0 to 0.5 mg/L) in the presence or absence of Kin promotes root growth instead of callus, while high concentrations (above 3.0 mg/L) retard the callus formation. The embryogenic calli from this optimized PGRs combination were successfully formed shoots in MS medium supplemented with 2 mg/L BAP and 1 mg/L NAA, followed by rooting in PGRs-free MS medium. This finding provides an efficient protocol for callogenesis and somatic embryogenesis of MARDI Siraj 297, since this is the first published report regarding somatic embryogenesis induction of this cultivar.</p> </abstract>