Thuja Occidentalis L.

The genera described in this book can be separated

t. Leaves scale-like, large, spirally arranged.

&

2. Leaves scale-like, I

more or less straight, pointed, Rfl^r^

3. Leaves scale-like, very small, overlapping, Jfo

4, Leaves needle-like, inserted singly on the stem. \

5. Leaves needle-like, two to five borne apically on a dwarf shoot.

6. Leaves needle-like, in groups on woody short shoots.

7. Leaves linear, I inserted singly on the stem. IJ

!J

8. Leaves with flat blades similar to those of broad-leaved trees.

on the basis of the form and arrangement of leaves.

Araucaria

p. 24

Sequoiadendron, Cryptomeria, Juniperus sabina

p. 25 to 27

Thuja, Libocedrus, Chamaecyparis, Cu-pressus

p. 28 to 31

Picea, Abies, Pseudotsuga, Juni per us communis

p. 32 to 39

ftwo-need led

Pinus J three-needled

[five-needled

p. 40 to 45 p. 46 to 48 p. 49 to 51

Cedrus, Larix

p. 52 to 53

Tsuga, Taxodium, Taxus, Sequoia . .

p. 54 to 57

Ginkgo

p. 58

Araucaria Araucana Molina

ARAUCARIA ARAUCANA (Molina) Koch (Monkey Puzzle, Chile Pine)

This evergreen conifer is a native of Chile, where it reaches a height of 150 feet. It is pyramidal in form but old trees lose their lower branches and become round-topped. The lateral branches arise in whorls of three or four and become pendulous with age. The dense spirally arranged leathery lanceolate dark green leaves are one to two inches long. The ovoid female cones are four to seven inches long and each pointed scale bears a single large seed on its upper surface which remains attached to the scale when it is shed. Of the 10 species of Araucaria this is the only one which can be grown outdoors in temperate regions. It is not cultivated for timber but is often planted in parks and gardens in Britain. (Araucariaceae)

Big Evergreen Trees

SEQUOIADENDRON GIGANTEUM Buchholz (Big Tree) This enormous evergreen tree is a native of a small area of the Sierra Nevada in central California where some specimens are well over 300 feet high and are estimated to be at least 1500 years old. The straight tapering trunk is covered with a thick spongy reddish-brown bark. The tree is narrowly pyramidal and the slender drooping branches are covered with dense spirally arranged, pointed leaves about % inch long. The ovoid female cone is two to three inches long and each woody scale bears several small winged seeds on its upper surface.

The Big Tree grows best in moist soils and although of no economic value many fine specimens can be seen in Britain especially in western areas. (Taxodiaceae)

Cryptomeria Japonica Don

CRYPTOMERIA JAPONICA Don, D. (Japanese Cedar) Although one of the commonest conifers in Japan, where its wood is widely used in construction work, this attractive species is not a true cedar but is more closely related to the Big Tree. It is a variable evergreen tree and may reach 200 feet. The slender green branch-lets bear spirally arranged curved awl-shaped leaves, Vx fo % inch long. The terminal dark-brown globose cone is % to '/t inch across. Each woody scale has a. terminal recurved spine and bears two or three small roughly triangular seeds.

The Japanese Cedar was Introduced Into Britain in 1842 and grows well on moist soils in sheltered positions. A number of varieties have been described, based on distinct differences in habit. (Taxodiaceae)

JUNIPERUS SABINA L. (Savin)

The Savin is a shrubby tree about 15 feet high which commonly grows in mountainous limestone areas of southern and central Europe. Most of the slender branches are covered by opposite pairs of overlapping scale leaves but occasional branches are found bearing the juvenile form of awl-shaped leaves. The ovoid berrylike cone is about 7, inch across and usually contains three seeds.

The foliage has an unpleasant smell when rubbed. Oil of savin, which is used in medicine as a diuretic, is distilled from the leaves and shoots. The branches are sometimes used to make walking-sticks. Savin is a hardy tree which will grow in the poorest soils; it has been cultivated in England since the middle of the 16th century. (Cupressaceae)

Thuja Occidentalis

THUJA OCCIDENTALIS L. (American Arbor-vitae) This species is common in North America where it forms dense forests on swampy ground. It reaches 60 feet in height and (he trunk is often forked near the base. The young horizontal branches are flattened and covered with opposite pairs of small pointed dark green leaves. The woody cones ^re up to % inch long and bear small marginally winged seeds. Many varieties are known and it has been extensively planted in Britain for hedges and ornamental purposes since the end of the 16th century.

THUJA ORIENTAUS L, (Chinese Arbor-vitae) is a smaller tree with vertical branchlets and minute leaves. Each scale of the ovoid cone has a conspicuous terminal hook. Three other species are known, the most important being T. plicata which forms large forests in North America. (Cupressaceae)

Libocedrus Decurrens

UBOCEDRUS DECURRENS Torrey (Incense Cedar) This conifer, which is a native ot the Pacific seaboard of America, is a handsome slender pyramidal tree up to 150 feet high. It has a reddish furrowed bark and the vertical systems of branchlels are covered with alternating opposite pairs of elongated dark green scale leaves. The solitary cylindrical cones are less than an inch long when ripe and consist of six narrow woody scales each bearing one or two winged seeds. It was introduced into Britain about 100 years ago and grows well here especially on moist soils. Although not used in forestry it is frequently planted in parks and gardens. The close-grained fragrant wood is often used in America for carpentry and furniture construction. Eight other species are known. (Cupressaceae)

Cipres Lawson Bonsai

(Lawson Cypress)

Lawson Cypress is a native of Oregon and California where it reaches 200 feet in height. It is a dense pyramidal tree with flattened branchlets covered by alternate, unequal pairs of opposite leaves. The globular cones are less than ^ inch across and each woody scale bears two to five marginally winged seeds. Although introduced into Britain tittle more than a century ago it is very hardy and is perhaps the most extensively planted conifer in gardens. It is extremely variable in habit and a large number of varieties have been described.

Several other species are known including C. nootka-tensis (Yellow Cypress) from North America and C, pisifera (Sawara Cypress) from Japan, both of which are also variable in habit. (Cupressaceae)

Cipres Nootka

CuprasuS arizonica

Cupressus semperrirens

CUPRBSSUS SBMPBRVIRBNS L. (Mediterranean Cypress)

This is the Cypress referred to in classical writings and is found throughout the Mediterranean basin. It has a spreading habit and may reach 150 feet in height. The small scale leaves are in four rows and are more or less the same size. The spherical woody cone is over an inch long and each scale bears up to 20 winged seeds,

CUPRBSSUS ARIZONICA Greene (Arizona Cypress) This is a pountain species which grows in Arizona and North Mexico where it reaches a height of 70 feet. Generally Cupressus spp. can only be successfully grown in the milder parts of Britain. There are about a dozen species including C, macrocarpa (Monterey Cypress) confined to a coastal strip of California about two miles long, and the beautiful Kashmir Cypress (C. cashmeriana). (Cupressaceae)

Juniper Trees Florence

JUNIPBRUS COMMUNIS L. (Common Juniper) This species is widespread throughout Europe, northern Asia and North America. It is one of the three native conifers in Britain and is particularly common on chalk and limestone hills. It is a small slow-growing shrub or tree rarely exceeding 30 feet in height. The narrow spreading leaves are about % inch long and end in sharp points. The globular, bluish-black cones are fleshy when ripe and contain one to three seeds. There are many varieties including the Hedgehog Juniper (v. echiniformis), a small round bush one to two feet high, and the Irish Juniper (v. hibernica) which has dense erect branches.

Oil of juniper is extracted from the unripe cones which are also used for flavouring gin, (Cupressaceae)

Sitka Spruce Ireland Cones

PICEA ABIES (L.) Karsten (Norway Spruce) This conifer is widespread in northern and central Europe where it may reach 200 feet in height. IL has a reddish bark and non-resinous buds. The spirally arranged narrow dark green leaves are up to an inch long. The brown cylindrical pendulous cone is four to si* inches long. It ripens in the autumn and opens to shed the winged seeds during the following spring. The Norway Spruce is very hardy and extensively planted in Britain. The timber is used for many kinds of construction work and as a source of wood pulp. This is also the conifer most often used for Christmas trees. There are many recognized varieties including dwarf forms useful for rock gardens. (Pinaceae)

Arix European Pinaceae

Picea nigra

PICEA MARIANA (Mill.) Britton, E, E. Stearns&Poggenb. (Black Spruce)

This tree is common throughout Canada and the northeastern United States, It reaches 75 feet in height and is easily recognized by its young hairy shoots and crowded bluish-green leaves about % inch long. The brown ovoid pendulous cones ari? little morethan an inch long and remain on the tree for several years after the winged seeds are shed. It is of no value for forestry in Britain but is often grown In gardens.

PICEA SITCHENSIS (Bong.) Carrière (Sitka Spruce), also from North America, is extensively grown in Britain where it thrives in a wide range of conditions from the coast to exposed mountains. It reaches 200 feet in height and has narrow flattened sharply pointed leaves, (Ptnaceae)

Himalayan Spruce

PICEA SMITHIANA (Wall.) Boiss. (West Himalayan Spruce)

This is a beautiful tree up to 200 feet high in its native habitat with pendulous branches and narrow spreading incurved leaves one to two inches long. The brown cylindrical cones are four to eight inches long. It is hardyin Britain and is a valuable ornamental tree but not used in forestry.

About 30 species of Picea are known, differing in the form of their leaves and cones, (Pinaceae)

0 0

Post a comment