Ilex aquifolium

Ilex aquifolium (holly, common holly, English holly, European holly, or occasionally Christmas holly), is a species of holly native to western and southern Europe, northwest Africa, and southwest Asia. It is regarded as the type species of the genus Ilex, which by association is also called 'holly'. It is an evergreen tree or shrub found, for example, in shady areas of forests of oak and in beech hedges. In the British Isles it is one of very few native evergreen trees. It has a great capacity to adapt to different conditions and is a pioneer species that repopulates the margins of forests or clearcuts. I. aquifolium can exceed 10 m in height, but is often found at much smaller heights, typically 2–3 m (6.6–9.8 ft) tall and broad, with a straight trunk and pyramidal crown, branching from the base. It grows slowly and does not usually fully mature due to cutting or fire. It can live 500 years, but usually does not reach 100. Ilex aquifolium is the species of holly long associated with Christmas, and previously the Roman festival of Saturnalia. Its glossy green prickly leaves and bright red berries (produced only by the female plant) are represented in wreaths, garlands and cards wherever Christmas is celebrated. It is a subject of music and folklore, especially in the British tradition. It is also a popular ornamental shrub or hedge, with numerous cultivars in a range of colours. Ilex aquifolium grows to 10–25 m (33–82 ft) tall with a woody stem as wide as 40–80 cm (16–31 in), rarely 100 cm (39 in) or more, in diameter. The leaves are 5–12 cm long and 2–6 cm broad; they are evergreen, lasting about five years, and are dark green on the upper surface and lighter on the underside, oval, leathery, shiny, and about 5 to 9 cm long. In the young and in the lower limbs of mature trees, the leaves have three to five sharp spines on each side, pointing alternately upward and downward, while leaves of the upper branches in mature trees lack spines. The flowers are white, four-lobed, and pollinated by bees. Holly is dioecious, meaning that there are male plants and female plants. The sex cannot be determined until the plants begin flowering, usually between 4 and 12 years of age. In male specimens, the flowers are yellowish and appear in axillary groups. In the female, flowers are isolated or in groups of three and are small and white or slightly pink, and consist of four petals and four sepals partially fused at the base. The fruit only appears on female plants, which require male plants nearby to fertilise them. The fruit is a drupe (stone fruit), about 6–10 mm in diameter, a bright red or bright yellow, which matures around October or November; at this time they are very bitter due to the ilicin content and so are rarely eaten until late winter after frost has made them softer and more palatable. They are eaten by rodents, birds and larger herbivores. Each fruit contains 3 to 4 seeds which do not germinate until the second or third spring. Today, holly is found in western Asia and Europe in the undergrowth of oak forest and beech forest in particular, although at times it can form a dense thicket as the dominant species. It requires moist, shady environments, found within forests or in shady slopes, cliffs, and mountain gorges. Along the west coast of the United States and Canada, from California to British Columbia, non-native English Holly has proved very invasive, quickly spreading into native forest habitat, where it thrives in shade and crowds out native species. It has been placed on the Washington State Noxious Weed Control Board's monitor list, and is a Class C invasive plant in Portland.