This is an excerpt from the Book called “Eyewitness Tree” by David Burnie. Continue reading to learn more about Tree Leaves, thanks to the author.
Leaves take in energy from sunlight and use it to turn carbon dioxide and water into sugars. These sugars can then be used as a fuel, or they can form cellulose, the substance that forms the tree’s cells. Leaves of broadleaved trees are either simple or compound.
Many willows have long, narrow leaves with silvery hairs on the undersides.
Symmetrical heart-shaped leaves are uncommon the judas tree (above and katsura have them.
The shape of the cultivated cherry leaf is common.
In summer, unequal leaves grown by limes often become covered with honeydew made by sap-sucking insects.
In a variegated leaf, the green pigment chlorophyll is reduced or absent in parts. These leaves rarely survive in nature.
The oval leaves of some magnolias can grow up to 1 ft (30 cm) long.
White poplar leaves have downy undersides.
The sweet chestnut’s jagged, tough leaves are a familiar sight in Europe.
Other pigments mask the green chlorophyll, in dark-colored leaves.
The two species of tulip tree- one North American and the other Chinese-have large, flat-ended leaves unlike any other tree. This specimen is a young leaf with two points; large mature leaves usually have four points.
Catalpas, or Indian bean trees, have some of the largest of all simple deciduous leaves, reaching up to 1 ft. (30 cm0 in length. Catalpas are natives of the subtropics.
The primitive ginkgo’s fanlike leaves have not changed for more than 200 million years.
Most deciduous oaks have lobed or toothed leaves, which feel leathery Evergreen oaks have short, lance-shaped leaves.
Maple leaves have handlike shapes. However, some species, such as the snake-bark maples of China, Japan, and North America, have scarcely lobed leaves. The leaves of another maple, the box elder, are compound.
Although plane leaves are hand-shaped, planes are not related to maples, as their fruits show. Plane leaves have a tough, glossy surface that is washed clean by rain, helping them to grow in polluted, city air.
Some of the biggest leaves found on broadleaved trees are compound, and can measure up to 3 ft (1 m) from stalk to tip. They grow from a single bud, and when autumn comes many of them fall off in one piece, leaving a large leaf scar where they were attached to the tree.
Compound leaves with three leaflets are rare; some maples and the American hop tree do have them. The European laburnum is grown for its yellow flowers.
The hickories (such as this bitternut) and walnuts make up distinctive family of trees. All have large compound leaves up to 30 in (75 cm) long.
Rounded, paired leaflets often mean that a tree belongs to the pea family. It includes the North American robinia, or black locust, shown.
The staghorn sumac’s elegant leaves are a familiar sight on waste ground in the United States and in gardens in Europe. The forked stems of this shrubby tree are covered in fur.
The rowan, or mountain ash, was its feathery leaves, grows from urban streets to rocky hills.
In Europe, the ash is the most common large tree with compound leaves. In the autumn, the ash is slow to shed its foliage. According to folklore, the ash tree possessed medicinal powers, and it was believed that a sick child would be cured if he or she was passed through the branches of the ash.
The leaves of the horse chestnut family have fingerlike leaflets. The horse chestnut has seven or nine leaflets; the North American buckeyes usually have five.
The Hercules club from North America has huge leaves that are twice compound: each leaflet is attached to a side stalk. The leaves may grow up to 3 ft (1 m) long and almost as wide.
Doubly divided leaves are very unusual, and only one tree, the Kentucky coffee tree from North America (though not related to the true coffee bush), is common.
