Tree and Leaf Trivia Quiz

The Norway or European spruce (Picea abies) is a majestic evergreen conifer that can reach a height of almost 60 m (197 ft). It grows in much of northern and northeastern Europe, as well as in various mountain areas of the continent. Norway spruce are also widely planted in parks and gardens, and cultivated for use as Christmas trees. The largest member of the spruce family is the enormous Sitka spruce (Picea sitchensis), which has also been introduced to western Europe as a source of timber.

Like all coniferous trees, the Norway spruce does not have the flat, blade-like leaves that flowering plants (angiosperms) possess. Its short, needle-shaped leaves are dark green, with blunt tips and a distinctive four-sided cross-section. Each needle is attached to a branchlet by a peg-like base called pulvinus - which is not present in other trees of the family Pinaceae. Pulvini remain on the branch even after the needles fall. As the photo shows, needle-covered branchlets (which generally grow downward) look a bit like bottle brushes.

In spite of its common name, the horse chestnut (Aesculus hippocastanus) is not related to the sweet chestnut (Castanea sativa), though the leaves and fruits of these two tree species are somewhat similar. This large, stately tree, believed to be native to the Balkan Peninsula, is instead related to maples, which also belong to the family Sapindaceae. The horse chestnut can grow to a height of almost 40 m (131 ft); it is widely grown as a ornamental tree because of its lush foliage and showy spring flowers.

The leaves of the horse chestnut have a very distinctive shape, which in botany is described as palmately compound. As its name suggests, palmate denotes a shape similar to a human hand: a palmately compound leaf consists of leaflets radiating from the same stalk (petiole). They are also opposite, meaning that leaves are attached in pairs at each node on the stem. As the photo shows, a horse chestnut leaf usually has 5-7 leaflets, and can grow to a very large size - up to 60 cm (24 in) across. These leaves turn yellow and red in autumn before falling.

Native to eastern Canada and the eastern US, where it is a major component of hardwood forests, the sugar maple (Acer saccharum) is the main source of the sap used to produce maple syrup. Forest-grown trees are usually taller than those that grow in open areas: they can reach heights of 35 m (115), occasionally even more. Sugar maples are long-lived, and thrive in cooler climates, as they require low temperatures for seed germination.

The leaves of the sugar maple are opposite and palmate, with five lobes - two small ones on each side, and three larger, deeply notched ones. Maples are renowned for the spectacular colours of their autumn foliage, and sugar maples are among the most beautiful, ranging from golden yellow to a vivid, almost fluorescent orange-red. A distinctive feature of these trees is their foliage's tendency to turn unevenly, with some parts of the tree changing colour weeks before the rest. The maple leaf that appears on the Canadian flag, though often identified with a sugar maple leaf, is not supposed to represent any particular species.

One of the most recognizable of trees, the weeping willow (Salix babylonica) is native to northern China, but has been cultivated in other parts of Asia and Europe for thousands of years; it has also been introduced to North America. Most of the cultivated varieties of weeping willow, however, are hybrids, which can withstand more humid conditions than those of the area where the tree originated. This member of the family Salicaceae is characterized by its long, pendulous branches. It is a medium-sized tree, growing to a height of up to 25 m (82 ft), and rarely lives longer than 50-70 years. The specific name "babylonica" is a reference to Psalm 137, mentioning the "willows" growing along the banks of the Euphrates River - which, however, were not willows, but poplars.

Weeping willow leaves resemble those of other willow species, being long, narrow and pointed (lanceolate), with finely serrated margins; they are yellowish-green in colour, and turn golden yellow in autumn. They are alternate - with one leaf attached at each node in alternate directions along the stem - and arranged in a spiral pattern around the tree branches.

Found in eastern and central North America, the white oak (Quercus alba) is named after the light ash-grey colour of its bark. It is a magnificent tree that can grow to a height of 30 m (100 ft), and live to over 300 years of age, developing a very broad canopy with branches that spread parallel to the ground. Prized for its water- and rot-resistant wood, widely used in the making of barrels for the aging of wine and bourbon whiskey, the white oak is one of the primary components of the montane forests of the central and southern Appalachians.

The leaves of the white oak display the lobate shape typical of most members of the genus Quercus: as the photo shows, they are usually seven-lobed, and attached alternately to the stem. Young leaves are pinkish-red, maturing into a deep, glossy green; in the autumn, they turn gorgeous shades of rust brown, wine-red, or orange-red. As in other Quercus species, the dead leaves of the white oak often remain on the tree for the whole of the winter, eventually falling to the ground in the early spring - a phenomenon known as marcescence.

With its characteristic umbrella shape, the magnificent stone pine (Pinus pinea) is one of the symbols of its native Mediterranean region. It has also been introduced to parts of the world with a similar climate - such as South Africa, California, and parts of Australia - and is widely cultivated not only as an ornamental tree, but also for its edible seeds (known as pignoli or pinoli in Italian, and piñónes in Spanish). Stone pines can grow to a height of 25 m (80 ft), though they are usually shorter.

Like all members of the genus Pinus, the stone pine has long, flexible, needle-like leaves arranged in clusters called fascicles, as can be seen in the photo. Each fascicle, which can have up to seven needles, is produced from a small bud on a scale leaf. The needles can last on a tree for decades, depending on the species. Stone pine needles grow in fascicles of two, and can reach a length of 30 cm (12 in), though this is rather uncommon. Pine leaves have four stages of growth: juvenile leaves - which are much shorter, and generally blue-green in colour - can often be observed at the same time as adult leaves on young trees under 10 years of age.

Also known as southern blue gum, Eucalyptus globulus is an evergreen tree endemic to southeastern Australia (including Tasmania), where it occurs in four subspecies. Like other eucalyptus species, it is a tall tree - growing to an average height of 45 m (148 ft), but capable of reaching 100 m (330 ft) under ideal conditions. The blue gum is also naturalized in other parts of the world with a Mediterranean-type climate, where it is extensively planted both as a renewable source of timber and for ornamental purposes. The specific name "globulus" refers to the tree's spherical fruits, which can be seen in the photo.

The adult leaves of the blue gum eucalyptus are arranged alternately, and hang downwards. They are narrow and lance-shaped or curved, the same glossy green colour on both sides, and can grow to a length of 30 cm (11.8 in). Like the leaves of all members of the family Myrtaceae, blue gum leaves are covered in oil glands, from which eucalyptus oil - an essential oil with a number of practical applications - is extracted.

The name mimosa may refer to a number of different trees of the family Fabaceae. In the US, the name applies to Albizia julibrissin (also known as the Persian silk tree), while in Europe it denotes Acacia dealbata (also known as silver wattle). As its name implies, the former is native to southwestern Asia and eastern Asia; it is a deciduous tree with distinctive flowers that resemble tassels of silky pink thread. Acacia dealbata, on the other hand, is an evergreen native to Australia: it has small, spherical, bright yellow inflorescences, and can grow twice as tall as Albizia (up to 30 m/98 ft). Both trees are widely cultivated for ornamental purposes in the temperate regions of the world, though they also grow quickly and easily in the wild - so much that they are considered invasive species in some countries.

The leaves of trees in the family Fabaceae are in most cases pinnately compound - that is, with leaflets arranged in a feather-like pattern (pinna) on both sides of a common axis. Both Albizia julibrissin and Acacia dealbata have bipinnate leaves that resemble fern fronds, divided into 6-12 pairs of pinnae with 20-30 leaflets each - as can be seen in the photo. The leaves of Albizia julibrissin close during the night and when it rains, as emphasized by various local names for the tree - such as the Persian "shabkosb", meaning "night sleeper".

Also known as common holly, English holly, and Christmas holly, the European holly (Ilex aquifolium) is the type species of the genus Ilex, the only living genus of the family Aquifoliaceae. This genus comprises over 570 species of flowering plants, found in subtropical and tropical areas of the world. As its name implies, the European holly is native to Europe, Western Asia and North Africa, though it has also been introduced to North America, where it is considered an invasive species. The European holly is an evergreeen, and can grow to a height of 25 m (82 ft), though it is usually shorter. It is often found in shady, moist areas of oak and beech forests, and can be quite long-lived. It is also widely grown as an ornamental plant, its branches with its bright red berries a traditional Christmas decoration.

Holly leaves are oval in shape, dark green on the upper side, and paler on the underside. They are glossy, with a characteristic leathery texture. In young trees and on the lower branches of mature trees, the leaves have spiny margins, with 5-7 spines on each side. In fact, this plant's specific name, "aquifolium", means "sharp leaf". Leaves on the upper branches of mature trees, however, have smooth margins.

The common fig (Ficus carica) is an ancient tree with a powerful cultural presence. It is the type species of the large Ficus genus (family Moraceae), which comprises over 800 subtropical and tropical plant species. Associated with the Mediterranean region and the Middle East, the common fig grows best in dry and sunny locations, and has been introduced to most parts of the world with a temperate, Mediterranean-type climate. It is a small tree, usually growing no taller than 10 m (33 ft), widely cultivated for its delicious fruits, which can be eaten fresh, dried, or made into jam.

Fig leaves can grow quite large - up to 25 cm (10 in) long and 18 cm (7 in) wide - and are deeply lobed, with three or five lobes (as shown in the photo) and slightly serrated edges. They are also fragrant, and will release a fresh, fruity scent - highly prized in perfumery - when crushed. In autumn, fig leaves will turn a bright yellow colour. In the Bible, fig leaves are mentioned as the makeshift covering used by Adam and Eve after eating the forbidden fruit: for this reason they are often featured in artistic depictions of the pair and other nude figures to cover the genital area.