Holly (Ilex aquifolium)
Kingdom Plantae – Plants
Subkingdom Tracheobionta – Vascular plants
Superdivision Spermatophyta – Seed plants
Division Magnoliophyta – Flowering plants
Class Magnoliopsida – Dicotyledons
Subclass Rosidae –
Order Celastrales –
Family Aquifoliaceae – Holly family
Genus Ilex L. – holly
Species Ilex aquifolium L. – English holly
Holly is a genus of about 400 species of flowering plants in the family Aquifoliaceae, and the only genus in that family. They are shrubs and trees from 2-25 m tall, with a wide distribution in Asia, Europe, north Africa, and North and South America. Widespread and common throughout Britain. With its bright red berries (found only on female plants), and shiny evergreen leaves, the native holly tree has been a symbol of midwinter festivals since pre-Christian times. It grows as a shrub or tree, and has a narrow, conical crown and smooth silver-greyish bark.
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The origin of the word Holly comes from the 11th Century Old High German hulis and Old English holegn both meaning Holly. The word hulis originates from an even older proto-Germanic word khuli a shortened derivation of the ancient Gaelic cuilieann both meaning Holly. Today in Modern Gaelic, Holly is still known as cuileann.
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As the holly is very shade-tolerant it is able to live as an understory species in woodlands where other trees cannot survive; it is especially associated with beech and oak woodlands. Pure holly woods are unique to Britain, and are ecologically equivalent to the evergreen cloud forests of South America and China. The holly grows up to 20m tall. The bark is smooth and grey coloured.
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The dark green leaves are spiny, and have a waxy texture. The leaves are simple, evergreen, and with widely-spaced, spine-tipped leaves. The holly tree is one of our few native evergreen trees. Its leaves are thick and shiny, and if you compare the leaves on the lower branches with those on the upper branches, you'll notice that the leaves lower down are much more prickly where as the higher leaves are smooth and rounded. This is a defense mechanism to deter grazing animals such as cows, horses and rabbits from eating the foliage.
Flowering occurs in May and June. Hollies are mostly dioecious, with male flowers, stamens with pollen and reduced, sterile stigma and female flowers stigma and, reduced sterile stamens with no pollen, on different plants, they occur in clusters, and are white in colour. Pollination is mainly by bees and other insects.
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The flowers are sometimes eaten by the larva of the Double-striped Pug moth. Other Lepidoptera whose larvae feed on holly include Bucculatrix ilecella (which feeds exclusively on holly) and The Engrailed.
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The round to oval, trizonocolpate Ilex pollen grain is very easily recognisable, as it has distinctive pilate sculpturing of the heavy exine, with rod-like elements with swollen heads. It can also have closely packed large clavae, variable in height and thickness, which taper towards the long, kinky furrows (Andrew 1984, Moore, et al. 1991). The pores within the furrows are not well defined.
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The fruit is a small globulose, red berry of 8 mm diameter, usually red when mature from August to October-December, with 4 seeds . Holly berries are mildly toxic and will cause vomiting and/or diarrhea when ingested by people. However they are extremely important food for numerous species of birds, and also are eaten by other wild animals. In the fall and early winter the berries are hard and apparently unpalatable. After being frozen or frosted several times, the berries soften, and become edible.
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All parts of the plant contain active principles (Aliharidis, 1987). Ilex aquifolium contains several toxins: saponin, phenolic compounds, terpenoides, sterols, alkaloids, anthocyanines (Thomas, 1980, Alikaridis 1987).
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Ingestion of berries may cause nausea, vomiting, abdominal pain and diarrhoea. Stupor and drowsiness have been seen in children after ingestion of large quantities of berries. Although lethal cases have been reported in older literature there are no recent reports of severe poisonings. Ingestion of Ilex aquifolium berries is mostly associated with gastrointestinal symptoms.
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Several active principles have been identified:
derivatives: vanillic acid, p-hydroxybenzoic acid (fruit); Anthocyanines: cyanidin-3-xylosylglucoside (fruit); pelargonidin-3-glucoside (fruit); Flavonoids: quercetin-3-rutinoside (leaves); Terpenoids: alpha-amyrin (bark, leaves, fruit); ursolic acid (leaves, fruit); oleanolic acid (leaves); ilex lactone (fruit); Sterols: ergosterol (leaves); beta-sitosterol (fruit); Alkaloids: theobromine; Fatty acids: pentadecanoic acid (leaves); palmitic acid (leaves); stearic acid (leaves); arachidic acid (leaves); oleic acid (leaves); linolenic acid (leaves); Alkanes: (leaves, fruit) Cyanogenic glucosides: 2 beta-D-glucopyranosyloxy-p-hydroxy-6,7-dihydromande-lonitrile (fruit, leaves, bark). (Alkaridis, 1987; Budzikiewicz, 1979; Willems, 1988)
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During winter storms, birds often take refuge in hollies, which provide shelter, protection from predators (by the spiny leaves), and food.
Holly berries are a very important source of food for birds during winter, and birds assist in the dispersal of holly berries away from the parent tree. Holly may also spread by vegetative reproduction, by 'runners'; furthermore, the tips of branches that touch the ground may take root, forming a bower around the trunk of the tree, which may be used by animals (and children) as a shelter.
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​In many Western cultures, holly is a traditional Christmas decoration, used especially in wreaths. Many of the hollies are highly decorative, and are widely used as ornamental plants in gardens and parks. The wood is heavy, hard and white; one traditional use is for chess pieces, with holly for the white pieces, and ebony for the black. Other uses include turnery, inlay work and as firewood. Looms in the 1800s used holly for the spinning rod. Because holly is dense and can be sanded very smooth, the rod was less likely than other woods to snag threads being used to make cloth.
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Unsurprisingly there is a rich wealth of folklore and custom surrounding this tree; the amount of berries produced is used as a means of divining whether there will be a harsh winter. A widespread and firmly held belief around Britain is that it is extremely bad luck to cut down a whole holly tree, although somewhat paradoxically, it is permitted to cut branches to bring into the house during winter. This belief has often led to hollies being retained even when the entire hedge to which they once belonged was destroyed. It was believed that holly planted around a house could protect the property against lightning strikes, sickness and witchcraft. In many farming areas, holly has been given to livestock as winter browse, and this practice continues today. Holly wood was used to make horsewhips for many years, as it was thought to have 'power over horses'. It was also believed to provide protection against fire. The most well-known holly-custom, however, is bringing boughs into the house in winter. Originally, holly was a fertility symbol because of the retention of the berries and shiny foliage throughout winter. It was also thought to protect a house from witchcraft and goblins. The pagan tradition of bringing holly indoors was accepted by Christianity; the spines of the leaves symbolising the crown of thorns, and the red berries representing the blood of Christ.
Holly comes in many varieties besides the familiar Christmas sort. The leaves are always evergreen, but there the similarities between all varieties ends. Some have smooth leaves - no prickles, some have prickles on their prickles, some have berries on their own, some have berries only if a partner is around and others don't have berries at all. Hollies are either male or female, only females have berries and usually only if there is a male around for pollination, though a few types are self fertile. Most berries are red, but some have orange or yellow berries. The leaf colour varies from bright through dark green and many are variegated with cream or yellow leaf margins.
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