North American maples

A number of North American species of Acer have been introduced into Britain and are frequently seen in parks and gardensAcer rubrum (Reci Maple). This is a deciduous tree reaching 100 feet in height with a smooth whitish bark. The opposite leaves, which are pale underneath, are similar to those of the Sycamore but the lobes are more pointed. They turn bright red in the autumn. The flowers are also red ant* "'e wings of the small fruit lie at an acute angle.

Acer saccharUm Marshall (Sugar Maple). This is abundant in eastern Nortl1 America where it attains a height of 100 leet. The 9rey l)3rk ¡s rough and the opposite leaves are similar to those 0( ttlB Norway Maple but the stalk has a watery juice. The flowers are yellowish-green and the wings ofthe ,ru't are divergent. In spite of the extensive cultivat'00 sUgar-cane and sugar-beet the extraction of saP by tappmg the trunk of A. saccharum each spring |s sti!l widely practised, Acer sacchari^1"71 I. (SiIver Maple). This beautiful tree comes from eastern North America. It is up to 120 feet high and has a smooth grey hark. The blades of the long-stalked opposite leaves have five narrow acute sharply toothed lobes anc' are silvery-white below. The flowers are green an^ w'ngs of the fruit are sickle-shaped. Acer nigrum Michx. (Black Maple), This is a deciduous tree up to 100 feet higt, wj(h a dark deeply fissured bark. The leaves fiave narrow stalks and broad blades with shallow pointed lobes. Like A. saccharum the Black Maple has a sugary Sap which is sometimes extracted commercially- (Aceraceae}

Black Maple Bark PhotosAcer Opalus

ACER OPALUS Mill. (Italian Maple) This is a hill tree with a range extending as far north as the Jura mountains. It is a small deciduous tree up to 30 feet high with a smooth bark. The opposite stalked leaves are about four inches long. The leaf blades are very variable in shape, somewhat similar to those of the Sycamore but with shorter, more obtuse lobes. The yellow flowers are in loose clusters and appear before the leaves unfold. The wings of the fruit are parallel or at an acute angle.

Apart from the European and North American Maples there are numerous species from Japan which are very ornamental and frequently seen in parks and gardens. The commonest of these is the Japanese Maple, A. palmatum, and its purple-leaved variety, v. atropurpureum. (Aceraceae)

Yellowwood Leaf Scar

CLADRASTIS TINCTORIA Rafin. (Yellow Wood) The Yellow Wood is a deciduous tree which is a native of eastern United States, It reaches a height of 40 feet and lias a dense crown of bent branches. The large alternate bright green leaves are pinnately compound with a terminal leaflet and three to five pairs of lateral leaflets. The smooth entire ovate leaflets are about five inches long but increase in size towards the tip of the leaf. The axillary buds are enclosed in the hollow base of the leaf stalk and 3re only exposed when the leaf is shed. The fragrant white flowers are about an inch long and are borne in pendulous groups. The flattened brown pod is up to four inches long.

This species is hardy in Britain and is occasionally planted in gardens. A yellow dye is extracted from the wood. (Caesalpiniaceae)

Coffee Tree Leaf

GYMNOCLADUS CANADENSIS Lam. (Kentucky Coffee Tree)

This native of North America is a large deciduous tree reaching 100 feet in height. It has a rough bark and long bare branches. The alternate bipinnate leaves are very large and have many ovate feaflets each about three inches long. In the autumn the leaflets are shed first, leaving the bare leaf stalks in place for a considerable time. There are separate male and female trees and the small greenish-white flowers are borne in loose terminal clusters. The fruit is a thick brown pod about nine inches long which contains a row of rounded seeds. It is occasionally grown in Britain as an ornamental tree but it is not very attractive after the leaflets have fallen. In America the wood is used for making furniture and it is believed that early settlers used the seeds for making a kind of coffee. (Caesalpiniaceae)

Caesalpiniaceae Cultivated Red Flowers

SOPHORA JAPONIC A L. (Pagoda Tree) This species is a native of China although it is commonly planted in Japan. It is a deciduous tree up to 80 feet high with a rough bark and green twigs. The alternate pinnate leaves have 11 to 15 ovate leaflets which are grey underneath. The greenish-white flowers are about >i inch across and are borne in erect terminal groups in early September. The fruit is a flattened constricted pod about three inches long.

This tree is not often planted in Britain although it grows well here and can tolerate the polluted atmosphere of industrial towns. Two other species are sometimes cultivated, S. tetraptera, a smaller tree with yellow flowers from New Zealand, and 5. viciifotia, a shrub from China. (Leguminosae)

ROBINIA PSEUDOACACIA L. (False Acacia) The False Acacia is a native of eastern North America but it has been widely planted and is now more or less naturalized in most North Temperate regions. It is a deciduous tree up to 80 feet high with twisted branches and a dark grey, deeply grooved bark. Suckers are often produced and when abundant form dense thickets. The alternate pinnate leaves have elliptical leaflets about two inches long. The swollen base of the leaf hides the small axillary bud and on each side is a sharp stipular spine. The fragrant white flowers appear in pendulous clusters during June. The dark brown pods are up to three inches long

Although not a long-lived tree the False Acacia is frequently grown for its ornamental value and in Europe it is planted on railway embankments and roadsides to consolidate the soil. There are several cultivated varieties including v. aurea with yellow leaves and v. decais-neana which has pink flowers. The wood is very durable when in contact with soil and is used for making gate posts.

There are about 20 species of Robinia all of which are natives of North America. The Rose Acacia, R. hispid a, is a small tree up to 12 feet high with hairy young branches and no spines. The deep pink flowers are about an inch across. In this country it is commonly grafted on to a stock of R. pseudoacacia. R. kelseyi is a similar species but the twigs are without hairs and bear thin prickles. The lanceolate leaflets are more than an inch long, the flowers are bright pink and the reddish pods are covered with stiff hairs. (Papilionaceae)

North American Tree Long PodsLaburnum Anagyroides

LABURNUM ANAGYROIDES Medicus (Laburnum, Golden Rain)

This is a native of central and southern Europe but it is very commonly grown in gardens in Britain and has become more or less naturalized. It is a small tree up to 25 feet high with a smooth greenish-brown bark. The alternate leaves have long stalks and slightly hairy trifoliate blades. The long pendulous racemes of golden yellow flowers appear in May. The flattened pods are about three inches long and persist on the tree during the winter. The small black seeds are poisonous. There are several attractive varieties in cultivation. The Purple Laburnum, known as L. adami, is a graft hybrid with a core of L. anagyroides covered by a thin layer of the tissues of the Purple Broom, Cytisus purpureus. The Scotch Laburnum, L. alpinum, is a native of central Europe. (Leguminosae)

Sapindaceae Juss

CEDRELA SINENSIS Juss.

A native of China this is a deciduous tree 50 to 70 feet high with a rough shredding bark. The large, alternate, pinnate leaves have lanceolate leaflets up to five inches long with entire margins. The small white scented flowers are borne in terminal pendulous inflorescences. The fruit is a small capsule containing winged seeds, tt is sometimes planted as an ornamental tree and can be confused with the Tree of Heaven, Ailanthus altissima (p. 136). (Meliaceae)

DISTINGUISHING FEATURES Cedrtl* Bark rough

Leaf scar with five vein endings

Leaflet margin entire Fruit a capsule, seeds winged

Ailanthus Bflrh smooth

Leal scar with seven vein ending*

Lo.iflel margin toothed Fruit one-seeded, winged

Ailanthus Altissima Tree Leaf Fruit

AILANTHUS ALTISSIMA Swingfe {Tree of Heaven) This deciduous tree is a native of China hut is commonly planted in Britain especially in town parks and squares. It is a quick-growing species with a smooth bark and is 50 to 70 feet in height. The large alternate leaves have broadly lanceolate leaflets which are coarsely toothed at the base. The smali greenish flowers which are borne in loose pendulous groups are often unisexual with the sexes on different trees. The flattened fruit is about one and a half inches long and contains a single seed.

In habit this is a particularly handsome tree with its curved branches and large leaves. However, it seeds abundantly and also produces suckers at a distance from the parent tree and can be a nuisance by invading adjacent ground. (Simarubaceae)

Juglans Regia Shell
shell and seed male cattiin

JUGLANS REGIA L. (Common Walnut) The Walnut occurs naturally from south-east Europe to China but has been planted in Britain for many years for its fruit and has become more or less naturalized in the south of England. It is a deciduous tree up to 100 feet high with a spreading crown and a whitish smooth bark. The large ultimate leaves have three to seven ovate entire leaflets. The small green male flowers are borne in dense pendulous catkins and the female flowers, which occur on the same tree, are in small groups on the twigs. The ovoid green fruit is up to two inches long and has a fleshy outer layer surrounding the 'walnut'. The latter has a brown woody shell and contains a single seed.

Apart from the fruits this tree is grown for its hard beautifully figured wood which is used in cabinet-making. (Juglandaceae)

Juglans Nigra

JUGLANS NIGRA L (Black Walnut) This large deciduous tree is a native of North America where it reaches a height of 100 feet. Unlike the Common Walnut it has a black ridged bark and the alternate leaves have 12 or more leaflets which are pointed and have finely toothed margins. The male flowers are in pendulous catkins and the female flowers in small groups. The green globose fruit is about two inches in diameter, hairy and ridged and encloses a small stone containing a single seed.

The Black Walnut is occasionally planted in parks and gardens in Britain. The fruits are of no value for eating but the hard durable wood is put to many uses, (Juglandaceae)

Juglandaceae Juglans Cinerea

fruits

JUGLANS CINEREA L. (Butternut) The Butternut is also a North American tree, it is deciduous, 60 to 80 feet high, and has a grey deeply fissured bark. The large alternate leaves have t1 to 19 lanceolate toothed leaflets which are somewhat hairy underneath. The flowers are grouped in short catkins and the green elongated fruit is covered by a sticky, glandular outer layer.

The 'nut' is edible but difficult to extract and the wood is not of the same quality as that of the previous two species. (Juglandaceae)

DISTINGUISHING FEATURES Juglans

Pith of the stem divided by septa

Outer layer of fruit does nut spfit into four valves

Carya

Pith of the stem not divided by septa

Outer layer of fruit splits into four valves

Fiava Fruit

CARYA OVATA Koch (Shellbark Hickory) This deciduous tree, like several other species belonging to the same genus, is a native of North America, it is up to 100 feet in height and has a pale grey bark which becomes detached in vertical strips. Most of the alternate leaves have five ovate toothed leaflets up to seven inches long. The male flowers are in pendulous catkins and the female flowers in groups of two to six at the ends of the young twigs. The ovoid fruit is whitish when mature and the outer fleshy layer opens to expose the thin-shelled one-seeded 'nut'.

The Shellbark Hickory is of value in America both for its edible fruit and durable wood. It is occasionally grown in Britain but the species which tolerates our climate best is the Bitter Nut, C. cordiformis, which is a tail tree with bright yellow buds and inedible fruits. (Juglandaceae)

Juglandaceae Tree

PTEROCARYA FRAXINIFOUA Koch (Caucasian Wing Nut)

This deciduous 1ree is a native of the Caucasus and Persia, It is normally 70 to 100 feet high with a single trunk covered by a deeply fissured bark, but near water the roots produce suckers which form a dense thicket. The large alternate pinnate leaves have 11 to 25 ovate leaflets with finely toothed margins. The dark brown axillary buds are borne on short stalks. The unisexual flowers occur in pendant catkins and the small brown irregularly shaped winged fruit contains a single seed. This tree grows rapidly and is sometimes seen in gardens. The few other species ol Pterocarya are natives of China. P. stenoplera, which is occasionally planted, reaches a height of 60 feet and has a winged leaf stalk. The elongated wtngs of the fruit are at an acute angle. {Juglandaceae)

Black Locust Leaf

GLEDITSCHIA TRIACANTHOS L. (Honey Locust) This large deciduous tree which can reach a height of 140 feet Is a native of eastern United States. The trunk bears groups of sharp stiff spines which are often branched. The alternate pinnate or bipinnate leaves have ovate toothed leaflets about one and a half inches long. The small greenish scented flowers are borne in erect inflorescences. The fruit is a brown flattened pod up to 18 Inches long which is often twisted. The Honey Locust grows quickly but is not often planted in Britain although on the Continent it is sometimes used for making hedges. Other species which are occasionally cultivated are the Water Locust, G. aquatica, from southern United States and the Japanese Locust, G. japonica. The true Locust, a native of Arabia, is Cera-tonia siliqua. (Caesalpiniaceae)

Sorbus Domestica Plant Tissue

SORBUS DOMESTICA L. {Service Tree) The Service Tree is a native of southern Europe, Asia Minor and North Africa. It is a deciduous tree up to 100 feet in height with a rough scaling bark, The alternate pinnate leaves have 11 to 21 toothed ovate leaflets over two inches long. The whitish flowers are small and borne in dense compound clusters. The brownish pear-shaped fruits are about an rnch long and have a hard bitter flesh which, like that of the Medlar, only becomes edible alter being softened by frost.

The Service Tree has been cultivated for many years throughout Europe and is sometimes planted in Britain, Although not a native in this country a single tree once existed in the Wyre Forest, Worcestershire, but this has now been destroyed. (Rosaceae)

Rowan Alternate Compound Pinnate

SORBUS AUCUPARIA L. (Mountain Ash, Rowan) This welt known species occurs throughout Europe and as far as the Caucasus. In Britain it is commonest in the north and west and ascends to over 3000 feet. It is a small deciduous tree up to 60 feet high with ascending branches. It has a smooth grey bark and the twigs are hairy when young. The alternate pinnate leaves have nine to 19 lanceolate sharply toothed leaflets which are dark green above and somewhat glaucous below, The small cream-coloured flowers are borne in dense fat clusters during May and June. In the autumn the tree bears many groups of bright red fleshy fruits. It is often planted in gardens for its attractive fruits but these are soon eaten by birds. Hybrids between this species and the White Beam, 5. aria (p. 96), are occasionally found. (Rosaceae)

White Beam Tree

KOELREUTERIA PANICULATA Laxm. (Pride of India) In spile of its common name this handsome deciduous tree is a native of China, It reaches a height of 50 feet and has a somewhat tortuous trunk and branches. Most of the iarge alternate leaves are pinnate or occasionally blpinnate and the ovate coarsely toothed leaflets, about three inches long, are lobed at the bare. The small yellow flowers appear in large terminal groups in August. The brown inflated fruit has thin papery walls and contains three black seeds.

This tree was introduced into Britain about 200 years ago. It is sometimes planted in gardens for its attractive foliage and it also fruits well here. (Sapindaceae)

Rhus Typhina Fruit

RHUS TYPHINA L. (Staghorn Sumach) This species is a native ot eastern United States. It is a small deciduous tree up to 25 feet high with a broad crown and black hairy twigs. The large alternate leaves have 13 or more lanceolate toothed leaflets about five inches long. The trees are unipexual and the minute flowers are borne in dense erect inflorescences. The flowers are greenish-yellow but the fruits are covered with red hairs.

It is frequently planted as an ornamental tree especially in town parks and gardens because it can tolerate a smoky atmosphere. The foliage is particularly attractive in the autumn when it turns red. The female trees are most usually planted for their crimson fruiting heads. However, it can be a nuisance to gardeners because of the long suckers it produces so freely. (Anacardiaceae)

fruits fruits

Box Elder Tree Acer Negundo

ACER NEGUNDO L. (Box Elder)

This tree, which is really a Maple, is widespread In North America where it reaches a height of 70 feet. In Britain it is frequently planted as an ornamental tree and is usually much shorter. It has a broad crown and fissured bark. The opposite compound leaves have a terminal leaflet and one or more pairs of lateral leafets which are coarsely toothed. The yellowish-green flowers are unisexual and are borne in pendulous groups on separate trees. The wings of the fruit are at an acute angle and sickle-shaped; they curve towards each other. The variegaled form which is sometimes planted, v. variegatum, has white edges to the leaflets and is always female. (Aceraceae)

Fraxinus Excelsior Aurea

FRAXINUS EXCELSIOR L. (Common Ash) The Ash occurs in Europe, western Asia and North Atnca. It is widespread in Britain and torms woods on calcareous soils particularly in the north and west. It is a tali deciduous tree occasionally 120 feet or more high. The rough bark is pale grey and the buds are covered by black scales. The opposite leaves are up to a foot long with seven to 13 lanceolate toothed leaflets. The small purplish flowers are borne in dense clusters on the sides of the twigs before the leaves unfold. The familiar brown twisted one-seeded fruits or 'keys' hang in conspicuous bunches.

Although not a particularly attractive tree a numoer of cultivated varieties are planted in gardens. It is also grown for its timber which is tough and durable. (Oleaceae)

Fraxinus Ornus Winter

FRAXINUS ORNUS L. (Manna Ash) This is a native of the Mediterranean region and Asia Mmor where it grows mainly on limestone hills. It is a deciduous tree 50 to 60 feel high with a smooth hark and greyish-brown buds. The pairs of opposite leaves have seven to nine stalked ovale pointed leaflets up to four inches long which have shall: w rounded marginal teeth. The small scented flowers have narrow white petals and are borne in dense clusters which appear al the same time as the leaves unlold. The flattened fruits are about an inch long.

The Manna Ash is frequently planted as an ornamental tree in Britain. The dried sugary sap extracted from the slem was formerly used medicinally. This is not the 'manna' referred lo in the Bible. (Oleaceae)

Fraxinus Americanus

FRAXINUS AMERICANUS L. (White Ash) The White Ash, which is similar to our native species, comes from North America. It is a tail deciduous tree up to 120 feet high with strong dark green or reddish-brown twigs. The pairs of opposite pinnate leaves have five to nine distantly toothed stalked lanceolate leaflets which are up to si* inches long and are whitish underneath. The very small white flowers have no petals and appear in clusters before the leaves. The winged Iruit is about two inches long and has the persistent calyx at its base.

This is sometimes planted as an ornamental tree in Britain. Other American species which are occasionally planted here are the Red Ash, F. pennsyhanica, and the Pumpkin Ash, F. profunda. (Oleaceae)

East Himalayan Horse Chestnut

AESCULUS HIPPOCASTANUM L. (Horse Chestnut) This is a native of south-east Europe, Persia and the Himalayas but has been widely planted in Europe and Britain and is often found semi-wild. It is a large deciduous tree up to 100 feet in height with arching branches and a stout trunk covered with a scaling dark brown bark. The smooth twigs bear large brown sticky buds. The opposite leaves have long stalks and compound palmate blades with usually seven sharply toothed leaflets. The white flowers are borne in erect conical heads during May. The terminal flowers are male but those at the base of the inflorescence have stamens and ovaries. The large green spherical fruit has an outer leathery wall covered with thick spines and contains one or occasionally two brown seeds. (Hippocastanaceae)

Aesculus Pavia Central Park

AESCULUS PAVIA (Red Buckeye) This small tree, which rarely exceeds 15 fee! in height, is a native of eastern United States. It has a smooth bark and long-stalked opposite leaves. The compound palmate blade usually has five lanceolate leaflets about five inches long with sharply toothed margins. The terminal inflorescences bear red flowers and the spherical brown fruits are smooth.

A. carnea is a fertile hybrid between A. hippocastanum and A. pavia. Generally it is a smaller tree than the Horse Chestnut and has red or pink flowers. Another species which is occasionally planted is the Sweet Buckeye, A. octandra. This has yellow flowers but cultivated varieties with pink or red flowers occur. (Hippocastanaceae)

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Responses

  • Ahmad
    What is the difference between a black locust and a honey locust?
    5 years ago
  • sebastian
    Is ailanthus red underneath?
    5 years ago
  • Diamanda Headstrong
    How to tell a true native butternut tree?
    5 years ago
  • Yolanda
    What does a black maple tree look like?
    2 years ago

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