Hedera helix

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iHedera helix

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Apiales
Family:	Araliaceae
Genus:	Hedera
Species:	H. helix

Binomial name

Hedera helix
L.

Hedera helix (Ivy or Common Ivy) is a species of ivy native to most of Europe and southwest Asia. It is an evergreen climbing plant, growing to 20-30 m high where suitable surfaces (trees, cliffs, walls) are available, and also growing as ground cover where there are no vertical surfaces. It holds on to tree bark and rock by means of short adhesive rootlets.

Image:Hadera helix.jpg

The leaves are alternate, 4-8 cm long, with a 3-10 cm long petiole; they are of two types, with palmately five-lobed juvenile leaves on creeping and climbing stems, and unlobed cordate adult leaves on fertile flowering stems exposed to full sun, usually high in the crowns of trees or the top of rock faces. The flowers are produced from late summer until late autumn, individually small, in 3-5 cm diameter umbels, greenish-yellow, and very rich in nectar, an important late food source for bees and other insects; the fruit are small black berries ripening in late winter, and are an important food for many birds, though poisonous to humans. The seeds are dispersed by birds eating the fruit.

Plants in southeast Europe and southwest Asia (Greece, Turkey) are treated as a distinct subspecies Hedera helix subsp. poetarum, differing in orange ripe fruit.

The closely related species Hedera canariensis and Hedera hibernica are often treated as varieties or subspecies of H. helix (Flora Europaea), though they differ in chromosome number so do not hybridise readily (McAllister 1982). H. helix can be best distinguished by its usually smaller and slightly more deeply lobed leaves and somewhat less vigorous growth, though identification is often not easy.

[edit] Cultivation and uses

It is widely cultivated as an ornamental plant, with numerous cultivars selected for such traits as yellow, variegated or deeply lobed leaves, purple stems, and slow, dwarfed growth.

In North America (where it is often known as "English Ivy"), it has become naturalised and is considered an invasive species, especially in the Pacific Northwest where the climate is similar to that in its native area.