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under these heads we shall give a short account of the equatorial forests.

to tropical as distinguished from temperate vegetation:

are

the various groups of palms, ferns, ginger-worts, and wild plantains, arums, orchids, and bamboos; and

part they take in giving a distinctive aspect to Palms. -- Although these are found throughout the tropics and a few species even extend into the warmer Parts of the temperate regions, they are yet so much more abundant and varied within the limits of the region We are discussing that they may be considered as among the most characteristic forms of vegetation of the equatorial zone. They are, however, by no means generally present, and we may pass through miles of forest without even seeing a palm. In other parts they abound ; either forming a lower growth in the lofty forest, or in swamps and on hill-sides sometimes rising up above the other trees. On river-banks they are especially conspicuous and elegant, bending gracefully over the stream, their fine foliage waving in the breeze, and their stems often draped with hanging creepers.

The chief feature of the palm tribe consists in the cylindrical trunk crowned by a mass of large and somewhat rigid leaves. They vary in height from a few feet to that of the loftiest forest-trees. Some are stemless, consisting only of a spreading crown of large pinnate leaves; but the great majority have a trunk slender in proportion to its height. Some of the smaller species have stems no thicker than a lead pencil, and four or five feet high ; while the great Mauritia of the Amazon has a trunk full two feet in diameter, and more than 100 feet high. Some species probably reach a height

of 200 feet, for Humboldt states that in South America he measured a palm, which was 192 English feet high. The leaves of palms are often of immense size. Those of the Manicaria saccifera of Para are thirty feet long and four or five fect wide, and are not pinnate but entire and very rigid. Some of the pinnate leaves are much larger, those of the Ruphia tadigera and Juximiliana regia being both sometimes more than fifty feet long. The fan-shaped leaves of other species are ten or twelve feet in diameter. The trunks of palms are sometimes smooth and more or less regularly ringed, but they are frequently armed with dense prickles which are sometimes cight inches long. In some species, the leaves fall to the ground as they decay leaving a clean scar, but in most cases they are persistent, rotting slowly away, and leaving a mass of fibrous stumps attached to the upper part of the stem. This rotting mass forms an excellent soil for ferns, orchids, and other semi-parasitical plants, which form an attractive feature on what would other. wise be an unsightly object. The sheathing margins of the leaves often break up into a fibrous material, sometimes resembling a coarse cloth, and in other cases more like horschair. The flowers are not individually large, but form large spikes or racemes, and the fruits are often beautifully scaled and hang in huge bunches which are sometimes more than a load for a strong man. The climbing palms are very remarkable, their tough, slender, prickly stems mounting up by means of the hooked midribs of the leaves to the tops of the loftiest forest-trees, above which they send up an clegant spike of foliage and flowers. The most important are the American Desmoncus and the Eastern Calamus, the

latter being the well-known rattan or cane of which chair-seats are made, from the Malay name “rotang." of the climbing group. They are very abundant in the drier equatorial forests, and more than sixty species are known from the Malay Archipelago. The stems (when cleaned from the sheathing leaves and prickles) vary in size from the thickness of a quill to that of the wrist; and where abundant they render the forest almost imin festoons from trees and branches, they rise suddenly

Passable. They lie about the ground coiled and twisted and looped in the most fantastic manner. They hang

The rattan-palms are the largest and most remarkable

loosely

through mid air up to the top of the forest, or coil

over shrubs and in thickets like endless serpents. They must attain an immense age, and apparently have almost unlimited powers of growth, for some are said to have been found which were 600 or even 1000 feet long, and if so, they are probably the longest of all vegetable growths. The mode in which such great lengths and tangled convolutions have been attained has already been explained in the general account of woody climbers. From the immense strength of these canes and the facility with which they can be split, they are universally used for cordage in the countries where they grow in preference to any other climbers, and immense quantities are annually exported to all parts of the world.

Uses of Palm-trees and their Products.—To the natives of the cquatorial zone the uses of palms are both great and various. The fruits of several speciesmore especially the cocoa-nut of the East and the peach-nut (Guilielma speciosa) of America--furnish

abundance of wholesome food, and the whole of the trunk of the sago-palm is converted into an edible starchour sago. Many other palm-fruits yield a thin pulp, too small in quantity to be directly eaten, but which when rubbed off and mixed with a proper quantity of water forms an exceedingly nutritious and agreeable article of food. The most celebrated of these is the assai of the Amazon, made from the fruit of Euterpe oleracca, and which, as a refreshing, nourishing, and slightly stimulating beverage for a tropical comtry, takes the place of our chocolate and coffee. A number of other palms yield a similar product, and many tliat are not caten by man are greedily devoured by a variety of animals, so that the amount of food produced by this tribe of plants is much larger than is generally supposed. The sap

which pours out of the cut flower-stalk of several species of palm when slightly fermented forms palm-wine or toddy, a very agreeable drink; and when mixed with various bitter herbs or roots which check fermentation, a fair imitation of beer is produced. If the same fluid is at once boiled and evaporated it produces a quantity of excellent sugar. The Arenga saccharifera, or sugar-palm of the Malay countries, is perhaps the most productive of sugar. A single tree will continue to pour out several quarts of sap daily for weeks together, and where the trees are abundant this forms the chief drink and most esteemed luxury of the natives. A Dutch chemist, Mr. De Vry, who has studied the subject in Java, believes that great advantages would accrue from the cultivation of this tree in place of the sugar-canc. According to his experiments it would produce an equal quantity of sugar of good

1

thousand feet, as in some of the volcanic mountains
of Java and on portions of the Eastern Andes. Beyond
the forests both to the north and south, we meet first
with woody and then open country, soon changing into
arid plains or even deserts which form an almost con-
tinuous band in the vicinity of the two tropics. On
the line of the tropic of Cancer we have, in America
the deserts and dry plains of New Mexico; in Africa the
Sahara ; and in Asia, the Arabian deserts, those of Beloo-
chistan and Western India, and further east the dry
plains of North China and Mongolia. On the tropic of
Capricorn we have, in America the Grand Chaco desert
and the Pampas; in Africa the Kalahari desert and the
dry plains north of the Limpopo ; wbile the deserts and
waterless plains of Central Australia complete the arid zone.
These great contrasts of verdure and barrenness occurring
in parallel bands all round the globe, must evidently
depend on the general laws which determine the distri-
bution of moisture over the earth, more or less modified
by local causes. Without going into meteorological
details, some of which have been given in the preceding
chapter, the main facts may be explained by the mode
in which the great aerial currents are distributed. The
trade winds passing over the ocean from north-east to
south-west with an oblique tendency towards the equator,
become saturated with vapour, and are ready to give
out moisture whenever they are forced upwards or in any
other way have their temperature lowered. The entire
cquatorial zone becomes thus charged with vapour-laden
air which is the primary necessity of a luxuriant vege-
tation. The surplus air (produced by the meeting of the
two trade winds) which is ever rising in the equatorial

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