Fam: Fagaceae
Species: Quercus ilex L.
Common name: Leccio - English: Evergreen oak, holm oak - Deutsch: Stein-Eiche
Etymology
According to some, the genus name is formed from two Celtic words, "Kaer" and "quer", which mean “beautiful tree” – the tree par excellence; the specific epithet, however, derives from Celtic and means “point”.
Description
Quercus ilex is an oak tree that, unlike other oaks, is evergreen. It is very long-lived, often reaching 1000 years of age. It has a dense, globular crown of dark green foliage formed by large branches that diverge early from the trunk.
The bark is initially smooth and grey; with age, it cracks into small, quadrangular plates, becoming dark, almost blackish. The current year's branches are grey due to their abundant diffuse hair, but later lose their pubescence and become shiny and greenish.
The leaves are persistent and last, on average, 2–3 years. They are leathery, with a short, tomentose petiole; the upper surface is dark green and shiny, while the lower is silvery grey owing to strong pubescence. A close examination reveals a great variety of shapes and shades of green, as the plant exhibits marked heterophylly – the leaf blade may vary on the same plant from elliptical to lanceolate, of variable length and width, with an entire margin, coarsely toothed or even with deep, mucronate teeth.
The male flowers are borne on long, pendulous filaments at the base of the current year’s branches. The individual male flower, which lacks a corolla and calyx, has a few anthers on short filaments and is protected by a hairy bract.
The female flowers are grouped in clusters of 6–7, borne on thin structures in the leaf axils, which later develop into twigs. The female flower lacks a corolla; the numerous scales covering the ovary protect it and later form the dome of the acorn.
Anthesis occurs from April until June, although re-flowering may occur in autumn, as indicated by the appearance of numerous male catkins and the plant turning yellow.
The acorns ripen within the same year, in late autumn. They occur in groups of 2–5 on very short peduncles. Their dimensions and colour are variable; they are dark brown with darker streaks when ripe. The apical part features a small, very evident thorn (mucrone), while the dome is covered by distinct scales that may extend over half or nearly the entire fruit.
Habitat
Quercus ilex is a typical constituent of the Mediterranean region (with a range limited to the Mediterranean coasts – the Olive Area).
Properties and Uses
The acorn is an important food source for wild fauna (e.g. wild boars) and domestic animals (e.g. pigs) and was historically a significant food resource for rural inhabitants.
Its resistant and hard wood is still used for various manufactured goods and as a valuable energy source during cold months for those who still use fireplaces.
Notes and Curiosities
The holm oak is a typical component of Mediterranean scrub, widespread along the coasts and in areas with a mild climate. It thrives on calcareous soils and is well-exposed to the sun, which it tolerates due to its high resistance to aridity. Generally, at least two hours of full sun daily are necessary for proper growth. The leaf margins are serrated in young plants, possibly as a defence against livestock.
The presence of tannins made the holm oak suitable for treating leather and hides in Greek and Roman times.
Along with the yew and cypress, the holm oak was considered a funeral plant and, like the cedar and cypress, symbolised immortality.
Several centuries-old holm oaks dominate the kiosk area in the garden. Visitors can admire the enchanting atmosphere of the Heller Botanical Park while enjoying a drink with friends, immersed in the dim light filtering through their thick, rounded foliage.