Holm oak (Quercus ilex). This tree is resistant to pollution and is often grown in cities. Photographed in Rome, Italy, where samples from the tree's

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Holm oak (Quercus ilex). This tree is resistant to pollution and is often grown in cities. Photographed in Rome, Italy, where samples from the tree's leaves have been used as indicators of air pollution levels.

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Size: 4430px × 2953px
Photo credit: © MICHAEL SZOENYI/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: air, angiosperm, angiosperms, biological, biology, botanical, botany, city, europe, european, evergreen, holly, holm, ilex, italy, nature, oak, plant, pollution, quercus, resistant, rome, tree, trees, urban