Ilex aquifolium | |
---|---|
Leaves and fruit | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Aquifoliales |
Family: | Aquifoliaceae |
Genus: | Ilex |
Species: | I. aquifolium |
Binomial name | |
Ilex aquifolium | |
Distribution map of Ilex aquifolium |
Ilex aquifolium, the holly, common holly, English holly, European holly, or occasionally Christmas holly, is a species of flowering plant in the family Aquifoliaceae, native to western and southern Europe, northwest Africa, and southwest Asia. [2] [3] [4] [5] 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 hardwood 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. [4] [5]
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 [6] 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. [7]
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. [2] [3] [4]
Along the west coast of the United States and Canada, from California to British Columbia, [8] 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. [9] [10] [11]
During the Cenozoic Era, the Mediterranean region, Europe, and northwest Africa had a wetter climate and were largely covered by laurel forests. Holly was a typical representative species of this biome, where many current species of the genus Ilex were present. With the drying of the Mediterranean Basin during the Pliocene, the laurel forests gradually retreated, replaced by more drought-tolerant sclerophyll plant communities. The modern Ilex aquifolium resulted from this change.[ clarification needed ][ citation needed ] Most of the last remaining laurel forests around the Mediterranean are believed to have died out approximately 10,000 years ago at the end of the Pleistocene.
Holly is a rugged pioneer species that prefers relatively moist areas, and tolerates frost as well as summer drought. The plant is common in the garrigue and maquis and is also found in deciduous forest and oak forest.
Pure stands of hollies can grow into a labyrinth of vaults in which thrushes and deer take refuge, while smaller birds are protected among their spiny leaves. After the first frost of the season, holly fruits become soft and fall to the ground serving as important food in its native regions for winter birds at a time of scarce resources.
The flowers are attractive as nectar sources for insects such as bees, wasps, flies, and small butterflies. The commonly-encountered pale patches on leaves are due to the leaf-mine insect Phytomyza ilicis .
It is an invasive species on the West Coast of Canada [8] and the United States as well as in Hawaii. [11] [12]
Holly is well known in epigenetics. Some cultivars have smooth leaf edges, or both smooth and prickly leaf edges on the same plant. In response to stress these cultivars can produce leaves with more prickles. [13]
Ilex aquifolium is widely grown in parks and gardens in temperate regions. [14] Hollies are often used for hedges; the spiny leaves make them difficult to penetrate, and they take well to pruning and shaping. [15]
Numerous cultivars have been selected, [16] of which the following have gained the Royal Horticultural Society's Award of Garden Merit: [17]
The hybrid Ilex × altaclerensis was developed at Highclere Castle in Hampshire, England, in 1835, a cross between I. aquifolium and the tender species I. perado . The following cultivars have gained the RHS AGM:
Holly berries contain alkaloids, theobromine, saponins, caffeic acid, and a yellow pigment, ilixanthin. [6] [32] [33] The berries are generally regarded as toxic to humans. [32] [33] Accidental consumption may occur by children or pets attracted to the bright red berries. The berries are emetic, possibly due to the compound ilicin. The leaves of yerba mate, also in the genus Ilex, are used to make a caffeinated beverage [34] called mate or Paraguayan tea. [35]
Between the thirteenth and eighteenth centuries, before the introduction of turnips, Ilex aquifolium was cultivated for use as winter fodder for cattle and sheep. Less spiny varieties of holly were preferred, and in practice the leaves growing near the top of the tree have far fewer spines, making them more suitable for fodder.
Ilex aquifolium was once among the traditional woods for Great Highland bagpipes before tastes turned to imported dense tropical woods such as cocuswood, ebony, and African blackwood.
Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus Pyrus, in the family Rosaceae, bearing the pomaceous fruit of the same name. Several species of pears are valued for their edible fruit and juices, while others are cultivated as trees.
A cherry is the fruit of many plants of the genus Prunus, and is a fleshy drupe.
Geranium is a genus of 422 species of annual, biennial, and perennial plants that are commonly known as geraniums or cranesbills. They are found throughout the temperate regions of the world and the mountains of the tropics, with the greatest diversity in the eastern part of the Mediterranean region.
Camellia is a genus of flowering plants in the family Theaceae. They are found in tropical and subtropical areas in eastern and southern Asia, from the Himalayas east to Japan and Indonesia. There are more than 220 described species; almost all are found in southern China and Indochina. Camellias are popular ornamental, tea, and woody-oil plants cultivated worldwide for centuries. Over 26,000 cultivars, with more than 51,000 cultivar names, including synonyms, have been registered or published.
Penstemon, the beardtongues, is a large genus of roughly 280 species of flowering plants native to North America from northern Canada to Central America. It is the largest genus of flowering plants endemic to North America. As well as being the scientific name, penstemon is also widely used as a common name for all Penstemon species alongside beardtongues.
Berberis aquifolium, the Oregon grape or holly-leaved barberry, is a species of flowering plant in the family Berberidaceae, native to western North America. It is an evergreen shrub growing 1–3 meters tall and 1.5 m (5 ft) wide, with pinnate leaves consisting of spiny leaflets, and dense clusters of yellow flowers in early spring, followed by dark bluish-black berries.
Alstroemeria, commonly called the Peruvian lily or lily of the Incas, is a genus of flowering plants in the family Alstroemeriaceae. They are all native to South America, although some have become naturalized in the United States, Mexico, Australia, New Zealand, Madeira and the Canary Islands. Almost all of the species are restricted to one of two distinct centers of diversity: one in central Chile, the other in eastern Brazil. Species of Alstroemeria from Chile are winter-growing plants, while those of Brazil are summer growing. All are long-lived perennials except A. graminea, a diminutive annual from the Atacama Desert of Chile.
Ilex opaca, the American holly, is a species of holly, native to the eastern and south-central United States, from coastal Massachusetts south to central Florida, and west to southeastern Missouri and eastern Texas.
Picea omorika, commonly known as the Pančić spruce or Serbian spruce, is a species of coniferous tree endemic to the Drina River valley in western Serbia, and eastern Bosnia and Herzegovina, with a total range of only about 60 ha, at 800–1,600 m (2,600–5,200 ft) altitude. It was originally discovered near the Serbian village of Zaovine, on Mount Tara, in 1875, and named by the Serbian botanist Josif Pančić; the specific epithet omorika is simply the Serbian word for the tree.
Juniperus chinensis, the Chinese juniper, is a species of plant in the cypress family Cupressaceae, native to China, Myanmar, Japan, Korea and the Russian Far East. Growing 1–20 metres tall, it is a very variable coniferous evergreen tree or shrub.
Berberis, commonly known as barberry, is a large genus of deciduous and evergreen shrubs from 1–5 m (3.3–16.4 ft) tall, found throughout temperate and subtropical regions of the world. Species diversity is greatest in South America and Asia; Europe, Africa and North America have native species as well. The best-known Berberis species is the European barberry, Berberis vulgaris, which is common in Europe, North Africa, the Middle East, and central Asia, and has been widely introduced in North America. Many of the species have spines on the shoots and all along the margins of the leaves.
Ilex crenata, also known as Japanese holly or box-leaved holly, is a species of flowering plant in the family Aquifoliaceae, native to eastern China, Japan, Korea, Taiwan, and Sakhalin.
Dicentra formosa is a species of flowering plant in the poppy family, Papaveraceae. With its fern-like foliage and inflorescence of drooping pink, purple, yellow or cream "hearts", this species is native to the United States' Pacific Northwest and West Coast of North America.
Acer japonicum, fullmoon maple, or downy Japanese-maple, is a species of maple native to Japan, on Honshū, Hokkaidō, Kyūshū, and also southern Korea.
Euonymus fortunei, the spindle, Fortune's spindle, winter creeper or wintercreeper, is a species of flowering plant in the family Celastraceae, native to east Asia, including China, Korea, the Philippines and Japan. E. fortunei is highly invasive and damaging in the United States, causing the death of trees and forest in urban areas.
Osmanthus heterophyllus, variously known as holly osmanthus, holly olive, and false holly, is a species of flowering plant in the olive family Oleaceae, native to eastern Asia in central and southern Japan and Taiwan.
Aster amellus, the European Michaelmas daisy, is a perennial herbaceous plant and the type species of the genus Aster and the family Asteraceae.
Ilex or holly is a genus of over 570 species of flowering plants in the family Aquifoliaceae, and the only living genus in that family. Ilex has the most species of any woody dioecious angiosperm genus. The species are evergreen or deciduous trees, shrubs, and climbers from tropics to temperate zones worldwide. The type species is Ilex aquifolium, the common European holly used in Christmas decorations and cards.
Ilex cornuta, commonly known as Chinese holly or horned holly, is a slow-growing, densely foliaged evergreen shrub in the Aquifoliaceae plant family. It is native to eastern China and Korea and attains a height of about 3 metres (9.8 ft). The leaves are usually 5-spined, between 3.5 cm and 10 cm long, oblong and entire. The fruits are red berries, which are larger than those of the European Holly.
Rosa 'Albéric Barbier' is a popular Hybrid wichurana rose cultivar that was bred in 1900 by Barbier Frères & Compagnie. Its parents were R. wichurana and the yellow hybrid tea 'Shirley Hibberd', named after the Victorian gardening writer (1825–1890).
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