Dante & the Pollution Resistant holm oak
Walking (virtually) under the shade of our forests of Fagaceae
History of the Holm Oak
Quercus ilex L. is an iconic species of the evergreen woods and Mediterranean maquis.
Plant fossils testify to its presence in the Mediterranean before humans, with other elements of an ancient flora that has disappeared. Specimens only survive now in North America and China.
How to recognize it? Its shape
It is an evergreen tree up to 25 meters high, with an expanded foliage and a beautiful dark green color.
The bark is initially grey and smooth, with age it becomes blackish and finely cracked in quadrangular plaques.
Quercus ilex L. (1967-09-27) by Anzalone B.Museo Erbario Sapienza
How to recognize it? Its leaves
The leaves are 4-9 cm long and half as wide, they are alternate, ovate-lanceolate and with a leathery consistency.
The lamina is glossy and dark green on the upper page and greyish with dense hairiness on the lower one.
Quercus ilex L. (1968-09-28) by Anzalone B.Museo Erbario Sapienza
The leaf margin is generally entire, may be toothed-spiny in young plants and suckers (stems arising at the base of the main trunk). Veins are pinnate.
Average leaf life is 2-3 years.
Quercus ilex L. (2021-06-16) by Giovanna AbbateMuseo Erbario Sapienza
How to recognize it? Its flowers
Male flowers are united in yellowish pendulous inflorescence; female flowers are solitary or gathered in groups of 2-3 on short peduncles.
The flowering period is between April and June.
Quercus ilex L. (2021-06-16)Museo Erbario Sapienza
How to recognize it? Its fruits
The fruits (acorns) are brown nuts, oval and pointed, enclosed up to half by a dome with hairy scales and appressed. They ripen between September and October, in the same year of flowering.
It is very common in Latium, including islands and coastal strips, but it can be found also in the inland areas, up to 1,500m. It grows on soils of different depths and nature, but not too clayey and without water stagnation; it prefers warm exposures and air humidity.
Where to find a Holm oak
The holm oak wood is a wood where the thick foliage reduces the passage of light and the undergrowth is poor in herbaceous and shrub species
In Italy it is cultivated in parks and street trees, because it adapts well to pruning and resists damage from pollution.
Curiosities...
The wood, hard and compact, is used to make parts of agricultural tools, presses and boats.
Acorns were used for the tanning of skins, because of their high tannin content, and since the Neolithic age as fodder and for the production of flour.
...and more curiosities
A study of fossil pollen preserved in sediments at the bottom of Lake Avernus has shown that on the slopes of the lake there was a dense ilex forest. Described by Dante in The Divine Comedy in verse 1: I found myself in a dark forest, for the straight path was lost.
The Sapienza Herbarium Museum holds over a million specimens and each one tells us an incredible story.
Texts and images by the staff of the Herbarium Museum, Sapienza University of Rome
Layout by Caterina Giovinazzo and Ilaria De Benedictis
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