GIANT TREES AND CHARACTERISTIC FORMS OF TROPICAL VEGETATION.
General Remarks--The Baobab--Used as a Vegetable Cistern--
Arborescent Euphorbias--The Dracæna of Orotava--The Sycamore--
The Banyan--The sacred Bo-Tree of Anarajapoora--The Teak Tree--
The Saul--The Sandal Tree--The Satinwood Tree--The Ceiba--
The Mahogany Tree--The Mora--Bamboos--The Guadua--Beauty and
multifarious Uses of these colossal Grasses--Firing the Jungle--
The Aloes--The Agave americana--The Bromelias--The Cactuses--The
Mimosas--Bush-ropes--Climbing Trees--Emblems of Ingratitude--
Marriage of the Fig Tree and the Palm--Epiphytes--Water Plants--
Singularly-shaped Trees--The Barrigudo--The Bottle Tree--Trees
with Buttresses and fantastical Roots--The Mangroves--Their
Importance in Furthering the Growth of Land-Animal Life among the
Mangroves--‘Jumping Johnny’--Insalubrity of the Mangrove Swamps--
The Lum Trees with formidable Spines.
Wherever in the tropical regions periodical rains saturate the earth,
vegetable life expands in a wonderful variety of forms. In the higher
latitudes of the frozen north, a rapidly evanescent summer produces but
few and rare flowers in sheltered situations, soon again to disappear
under the winter’s snow; in the temperate zones, the number, beauty,
and variety of plants increases with the warmth of a genial sky; but
it is only where the vertical rays of an equatorial sun awaken and
foster life on humid grounds that ever-youthful Flora appears in the
full exuberance of her creative power. It is only there we find the
majestic palms, the elegant mimosas, the large-leafed bananas, and so
many other beautiful forms of vegetation alien to our cold and variable
clime. While our trees are but sparingly clad with scanty lichens and
mosses, they are there covered with stately bromelias and wondrous
orchids. Sweet-smelling vanillas and passifloras wind round the giants
of the forest, and large flowers break forth from their rough bark, or
even from their very roots.
The number of known plants is estimated at about 200,000, and the
greater part of this vast multitude of species belongs to the torrid
zone. But if we consider how very imperfectly these sunny regions have
as yet been explored--that in South America enormous forest lands and
river basins have never yet been visited by a naturalist--that the
vegetation of the greater part of Central Africa is still completely
hidden in mystery--that no botanist has ever yet penetrated into
the interior of Madagascar, Borneo, New Guinea, South-Western China,
and Ultra-Gangetic India--and that, moreover, many of the countries
visited by travellers have been but very superficially examined--we
may well doubt whether even one fourth part of the tropical plants is
actually known to science.
After these general remarks on the variety and exuberance of tropical
vegetation, I shall now briefly notice those plants which, by their
enormous size, their singularity of form, or their frequency in the
landscape, chiefly characterise the various regions of the torrid zone.
The African Baobab, or monkey-bread tree (_Adansonia digitata_), may
justly be called the elephant of the vegetable world. Near the village
Gumer, in Fassokl, Russegger saw a baobab thirty feet in diameter and
ninety-five in circumference; the horizontally outstretched branches
were so large that the negroes could comfortably sleep upon them. The
Venetian traveller Cadamosto (1454) found, near the mouths of the
Senegal, baobabs measuring more than a hundred feet in circumference.
As these vegetable giants are generally hollow, like our ancient
willows, they are frequently made use of as dwellings or stables; and
Dr. Livingstone mentions one in which twenty or thirty men could lie
down and sleep, as in a hut. In the village of Grand Galarques, in
Senegambia, the negroes have decorated the entrance into the cavity of
a monstrous baobab with rude sculptures cut into the living wood, and
make use of the interior as a kind of assembly room, where they meet to
deliberate on the interests of their small community, ‘reminding one,’
says Humboldt, ‘of the celebrated plantain in Lycia, in whose hollow
trunk the Roman consul, Lucinius Mutianus, once dined with a party of
twenty-one.’ As the baobab begins to decay in the part where the trunk
divides into the larger branches, and the process of destruction thence
continues downwards, the hollow space fills, during the rainy season,
with water, which keeps a long time, from its being protected against
the rays of the sun. The baobab thus forms a _vegetable cistern_, whose
water the neighbouring villagers sell to travellers. In Kordofan the
Arabs climb upon the tree, fill the water in leathern buckets, and let
it down from above; but the people in Congo more ingeniously bore a
hole in the trunk, which they stop, after having tapped as much as they
require.[11]
The height of the baobab does not correspond to its amazing bulk,
as it seldom exceeds sixty feet. As it is of very rapid growth, it
acquires a diameter of three or four feet and its full altitude in
about thirty years, and then continues to grow in circumference. The
larger beam-like branches, almost as thick at their extremity as
at their origin, are abruptly rounded, and then send forth smaller
branches, with large, light green, palmated leaves. The bark is smooth
and greyish. The oval fruits, which are of the size of large cucumbers,
and brownish-yellow when ripe, hang from long twisted spongy stalks,
and contain a white farinaceous substance, of an agreeable acidulated
taste, enveloping the dark brown seeds. They are a favourite food of
the monkeys, whence the tree has derived one of its names.
From the depth of the incrustations formed on the marks which the
Portuguese navigators of the fifteenth century used to cut in the large
baobabs which they found growing on the African coast, and by comparing
the relative dimensions of several trunks of a known age, Adanson
concluded that a baobab of thirty feet in diameter must have lived
at least 5,000 years; but a more careful investigation of the rapid
growth of the spongy wood has reduced the age of the giant tree to
more moderate limits, and proved that, even in comparative youth, it
attains the hoary aspect of extreme senility.
The baobab, which belongs to the same family as the mallow or the
hollyhock, and is, like them, emollient and mucilaginous in all its
parts, ranges over a wide extent of Africa, particularly in the parts
where the summer rains fall in abundance, as in Senegambia, in Soudan,
and in Nubia. Dr. Livingstone admired its colossal proportions on the
banks of the Zouga and the Zambesi. It forms a conspicuous feature
in the landscape at Manaar in Ceylon, where it has most likely been
introduced by early mariners, perhaps even by the Phœnicians, as the
prodigious dimensions of the trees are altogether inconsistent with the
popular conjecture of a Portuguese origin.
[Illustration: DRAGON-TREE OF OROTAVA.]
Another tree very characteristic of Africa, and frequently seen along
with the baobab, is the large arborescent Euphorbia (_E. arborescens_),
surmounted at the top with stiff leaves, branching out like the arms
of a huge candelabra. It adds greatly to the strange wildness of the
landscape, and seems quite in character with the aspect of the unwieldy
rhinoceros and the long-necked giraffe.
Dracænas, or dragon-trees, are found growing on the west coast of
Africa and in the Cape Colony, in Bourbon and in China; but it is only
in the Canary Islands, in Madeira, and Porto Santo, that they attain
such gigantic dimensions as to entitle them to rank among the vegetable
wonders of the world.
Unfortunately, the venerable dragon-tree of Orotava, in Teneriffe,
which was already reverenced for its age by the extirpated nation of
the Guanches, and which the adventurous Bethencourts, the conquerors
of the Canaries, found hardly less colossal and cavernous in 1402 than
Humboldt, who visited it in 1799, was destroyed by a storm in 1871.
Above the roots the illustrious traveller measured a circumference
of forty-five feet; and according to Sir George Staunton, the trunk
had still a diameter of four yards, at an elevation of ten feet above
the ground. The whole height of the tree was not much above sixty-five
feet. The trunk divided in numerous upright branches, terminating in
tufts of evergreen leaves, resembling those of the pine-apple.
Next to the baobab and the dracæna, the Sycamore (_Ficus Sycomorus_)
holds a conspicuous rank among the giant trees of Africa. It attains a
height of only forty or fifty feet, but in the course of many centuries
its trunk swells to a colossal size, and its vast crown covers a large
space of ground with an impenetrable shade. Its leaves are about four
inches long and as many broad, and its figs have an excellent flavour.
In Egypt it is almost the only grove-forming tree; and most of the
mummy coffins are made of its incorruptible wood.
[Illustration: SYCAMORE.]
No baobab rears its monstrous trunk on the banks of the Ganges; no
dragon-tree of patriarchal age here reminds the wanderer of centuries
long past; but the beautiful and stately Banyan (_Ficus indica_)
gives him but little reason to regret their absence. Each tree is in
itself a grove, and some of them are of an astonishing size, as they
are continually increasing, and, contrary to most other animal and
vegetable productions, seem to be exempted from decay; for every branch
from the main body throws out its own roots, at first in small tender
fibres, several yards from the ground, which continually grow thicker,
until, by a gradual descent, they reach its surface, where, striking
in, they increase to a large trunk and become a parent-tree, throwing
out new branches from the top. These in time suspend their roots, and,
receiving nourishment from the earth, swell into trunks and send forth
other branches, thus continuing in a state of progression so long as
the first parent of them all supplies her sustenance.
[Illustration: BANYAN.]
The bended twigs take root, and daughters grow
About the mother-tree; a pillar’d shade
High overarch’d, and echoing walks between.
There oft the Indian herdsman, shunning heat,
Shelters in cool, and tends his pasturing herds
At loopholes cut through thickest shade.
These beautiful lines of Milton are by no means overdrawn; as a banyan
tree, with many trunks, forms the most beautiful walks and cool
recesses that can be imagined. The leaves are large, soft, and of a
lively green; the fruit is a small fig (when ripe of a bright scarlet),
affording sustenance to monkeys, squirrels, peacocks, and birds of
various kinds, which dwell among the branches.
The Hindoos are peculiarly fond of this tree; they consider its long
duration, its outstretching arms and overshadowing beneficence, as
emblems of the Deity; they plant it near their dewals or temples; and
in those villages where there is no structure for public worship they
place an image under a banyan, and there perform a morning and evening
sacrifice.
Many of these beautiful trees have acquired an historic celebrity; and
the famous Cubbeer-burr, on the banks of the Nerbuddah, thus called
by the Hindoos in memory of a favourite saint, is supposed to be the
same as that described by Nearchus, the Admiral of Alexander the
Great, as being able to shelter an army under its far-spreading shade.
‘High floods have at various times swept away a considerable part of
this extraordinary tree, but what still remains is near 2,000 feet in
circumference, measured round the principal stems; the overhanging
branches not yet struck down cover a much larger space; and under it
grow a number of custard-apple and other fruit trees. The large trunks
of this single colossus amount to a greater number than the days of the
year, and the smaller ones exceed 3,000, each constantly sending forth
branches and hanging roots to form other trunks and become the parents
of a future progeny.
‘About a century ago a neighbouring rajah, who was extremely fond of
field diversions, used to encamp under it in a magnificent style,
having a saloon, drawing-room, dining-room, bed-chamber, bath, kitchen,
and every other accommodation, all in separate tents; yet the noble
tree not only covered the whole, together with his carriages, horses,
camels, guards, and attendants, but also afforded with its spreading
branches shady spots for the tents of his friends, with their servants
and cattle. And in the march of an army it has been known to shelter
7,000 men.’[12] Such is the banyan--more wonderful than all the
temples and palaces which the pride of the Moguls has ever reared!
The nearly related Pippul of India, or Bo-tree (_Ficus religiosa_),
which differs from the banyan (_F. indica_) by sending down no roots
from its branches, is reverenced by the Buddhists as the sacred plant,
under whose shade Gautma, the founder of their religion, reclined when
he underwent his divine transfiguration. Its heart-shaped leaves,
which, like those of the aspen, appear in the profoundest calm to
be ever in motion, are supposed to tremble in recollection of that
mysterious scene.
The sacred Pippul at Anarajapoora, the fallen capital of the ancient
kings of Ceylon, is probably the oldest _historical tree_ in the world;
as it was planted 288 years before Christ, and hence is now 2,150
years old. The enormous age of the baobabs of Senegal, and of the
wondrous Wellingtonias of California, can only be conjectured; but the
antiquity of the Bo-tree is matter of record, as its preservation has
been an object of solicitude to successive dynasties; and the story of
its fortunes has been preserved in a series of continuous chronicles
amongst the most authentic that have been handed down by mankind.
[Illustration: THE SACRED BO-TREE OF ANARAJAPOORA.]
‘Compared with it, the Oak of Ellerslie is but a sapling, and the
Conqueror’s Oak in Windsor Forest barely numbers half its years.
The yew trees of Fountains Abbey are believed to have flourished
there 1,200 years ago; the olives in the Garden of Gethsemane were
full-grown when the Saracens were expelled from Jerusalem, and the
cypress of Somma in Lombardy is said to have been a tree in the time of
Julius Cæsar. Yet the Bo-tree is older than the oldest of these by a
century, and would almost seem to verify the prophecy pronounced when
it was planted, that it would ‘flourish and be green for ever.’[13]
Although far inferior to these wonders of the vegetable world in
amplitude of growth, yet the Teak tree, or Indian oak (_Tectona
grandis_), far surpasses them in value, as the ship-worm in the
water, and the termite on land, equally refrain from attacking its
close-grained strongly scented wood; and no timber equals it for
ship-building purposes.
It grows wild over a great part of British India; in the mountainous
districts along the Malabar coast, in Guzerat, the valley of the
Nerbuddah, in Tenasserim and Pegu. Unlike the oak and fir forests of
Europe, where large spaces of ground are covered by a single species,
the teak forests of India are composed of a great variety of trees,
among which the teak itself does not even predominate. After a long
neglect, which, in some parts, had almost caused its total extirpation,
Government has at length taken steps for its more effectual protection,
and appointed experienced foresters to watch over this invaluable tree.
Since 1843, millions of young plants have been raised from seeds, but
unfortunately the teak is of as slow growth as our oak, and many years
will still be necessary to repair the ruinous improvidence of the past.
On turning our attention to America we find that Nature, delighting
in infinite varieties of development, and disdaining a servile copy
of what she had elsewhere formed, covers the earth with new and no
less remarkable forms of vegetation. Thus, while in Africa the baobab
attracts the traveller’s attention by its colossal size and peculiarity
of growth, the gigantic Ceiba (_Bombax Ceiba_), belonging to the same
family of plants, raises his astonishment in the forests of Yucatan.
Like the baobab, this noble tree rises only to a moderate height of
sixty feet, but its trunk swells to such dimensions that fifteen
men are hardly able to span it, while a thousand may easily screen
themselves under its canopy from the scorching sun. The leaves fall
off in January; and then at the end of every branch bunches of large,
glossy, purple-red flowers make their appearance, affording, as one may
well imagine, a magnificent sight.
In British Honduras the Mahogany-tree (_Swietenia Mahagoni_) is found
scattered in the forests, attracting the woodman’s attention from a
distance by its light-coloured foliage, and its magnificent growth.
Such are its dimensions, and such is the value of peculiarly fine
specimens, that in October 1823 a tree was felled which weighed more
than seven tons, and at Liverpool was sold for 525_l._ The expense of
sawing amounted to 750_l._ more: so that the wood of this single tree,
before passing into the hands of the cabinet-maker, was worth as much
as a moderately sized farm.
‘Heedless and bankrupt in all curiosity must he be,’ says Waterton,[14]
‘who can journey through the forests of Guiana without stopping to
take a view of the towering Mora (_Mora excelsa_). Its topmast branch,
when naked with age, or dried by accident, is the favourite resort of
the toucan. Many a time has this singular bird felt the shot faintly
strike him from the gun of the fowler beneath, and owed his life to the
distance betwixt them. The wild fig tree, as large as a common English
apple-tree, often rears itself from one of the thick branches at the
top of the mora; and when its fruit is ripe, to it the birds resort for
nourishment. It was to an indigested seed passing through the body of
this bird, which had perched on the mora, that the fig tree first owed
its elevated station there. The sap of the mora raised it into full
bearing; but now, in its turn, it is doomed to contribute a portion
of its own sap and juices towards the growth of different species of
vines, the seeds of which also the birds deposited on its branches.
These soon vegetate and bear fruit in great quantities; so, what with
their usurpation of the resources of the fig-tree, and the fig-tree
of the mora, the mora, unable to support a charge which Nature never
intended it should, languishes and dies under its burden; and then the
fig-tree and its usurping progeny of vines, receiving no more succour
from their late foster-parent, droop and perish in their turn.’
Our stateliest oaks would look like pygmies near this chieftain of the
forests,’ who raises his dark green cupola over all the neighbouring
trees, and deceives the traveller, who fancies that a verdant hill is
rising before him. Its wood is much firmer than that of the fir, and
is, or will be, of great importance to the ship-builder. On the Upper
Barima alone, a river of Guiana hardly even known by name in Europe,
Schomburgk found the giant tree growing in such profusion that it could
easily afford sufficient timber for the proudest fleet that ever rode
the ocean.
The graceful tapering form of the _Gramineæ_, or grasses, belongs to
every zone; but it is only in the warmer regions of the globe that we
find the colossal _Bambusaceæ_, rivalling in grandeur the loftiest
trees of the primeval forest.
In New Grenada and Quito the Guadua, one of these giant grasses, ranks
next to the sugar-cane and maize as the plant most indispensable to
man. It forms dense jungles, not only in the lower regions of the
country, but in the valleys of the Andes, 5,000 feet above the level of
the sea. The culms attain a thickness of six inches, the single joints
are twenty inches long, and the leaves are of indescribable beauty. A
whole hut can be built and thatched with the guadua, while the single
joints are extensively used as water-vessels and drinking-cups.
India, South China, and the Eastern Archipelago are the seats of the
real bamboos, which grow in a variety of genera and species, as well
on the banks of lakes and rivers in low marshy grounds, as in the
more elevated mountainous regions. They chiefly form the impenetrable
jungles, the seat of the tiger and the python. Sometimes a hundred
culms spring from a single root, not seldom as thick as a man, and
towering to a height of eighty or a hundred feet. Fancy the grace
of our meadow grasses, united with the lordly growth of the Italian
poplar, and you will have a faint idea of the beauty of a clump of
bamboos.
The variety of purposes to which these colossal reeds can be applied
almost rivals the multifarious uses of the cocoa-nut palm itself.
Splitting the culm in its whole length into very thin pieces, the
industrious Chinese then twist them together into strong ropes, for
tracking their vessels on their numerous rivers and canals. The sails
of their junks, as well as their cables and rigging, are made of
bamboo; and in the southern province of Sechuen, not only nearly every
house is built solely of this strong cane, but almost every article of
furniture which it contains--mats, screens, chairs, tables, bedsteads,
bedding--is of the same material. From the young shoots they also
fabricate their fine writing-paper, which is so superior to the produce
of our own manufactories. Although the bamboo grows spontaneously and
most profusely in nearly all the southern portion of their vast empire,
they do not entirely rely on the beneficence of Nature, but cultivate
it with the greatest care. They have treatises devoted solely to this
subject, laying down rules derived from experience, and showing the
proper soils, the best kinds of water, and the seasons for planting
and transplanting the bamboos, whose use is scarcely less extensive
throughout the whole East Indian world.
At one season of the year the bamboos are easily destroyed by fire; and
as the great stem-joints burst from the expansion of the air confined
within, the report almost rivals the roar of cannon. In Sikkim firing
the jungle is a frequent practice, and Dr. Hooker, who often witnessed
the spectacle, describes the effect by night as exceedingly grand.
‘Heavy clouds canopy the mountains above, and, stretching across the
valleys, shut out the sky; the air is a dead calm, as usual in the deep
gorges; and the fires, invisible by day, are seen raging all around,
appearing to an inexperienced eye in all but dangerous proximity. The
voices of birds and insects being hushed, nothing is audible but the
harsh roar of the rivers, and occasionally rising far above it, that
of the forest fires. At night we were literally surrounded by them;
some smouldering like the shale-heaps at a colliery, others fitfully
bursting forth, whilst others again stalked along with a steadily
increasing and enlarging flame, shooting out great tongues of fire,
which spared nothing as they advanced with irresistible might. At
Darjiling the blaze is visible, and the deadened reports of the bamboos
bursting is heard throughout the night; but in the valley, and within a
mile of the scene of destruction, the effect is the most grand, being
heightened by the glare reflected from the masses of mist which hover
above.’[15]
The aloes form the strongest contrast to the airy lightness of the
grasses, by the stately repose and strength of their thick, fleshy,
and inflexible leaves. They generally stand solitary in the parched
plains, and impart a peculiarly austere or melancholy character to
the landscape. The real aloes are chiefly African, but the American
yuccas and agaves have a similar physiognomical character. The _Agave
americana_, the usual ornament of our hot-houses, bears on a short and
massive stem a tuft of fleshy leaves, sometimes no less than ten feet
long, fifteen inches wide, and eight inches thick! After many years
a flower-stalk twenty feet high shoots forth in a few weeks from the
heart of the plant, expanding like a rich candelabrum, and clustered
with several thousands of greenish-yellow aromatic flowers. But a rapid
decline succeeds this brilliant efflorescence, for it is soon followed
by the death of the exhausted plant.
In Mexico, where the agave is indigenous, and whence it has found
its way to Spain and Italy, it is reckoned one of the most valuable
productions of Nature. At the time when the flower-stalk is beginning
to sprout, the heart of the plant is cut out, and the juice, which
otherwise would have nourished the blossom, collects in the hollow.
About three pounds exude daily, during a period of two or three
months. After standing for a short time, the sweet juice undergoes a
vinous fermentation, and the stranger, when once accustomed to its
disagreeable odour, prefers the _pulque_ to all other wines, and joins
in the enthusiastic praises of the Mexican.
The American bromelias likewise resemble the aloes of torrid Africa
by the form and arrangement of their leaves. To this useful family
belongs the pine-apple (_Bromelia Ananas_), which grows best and
largest in Brazil, where it is so common that the pigs fatten on the
fruit. Formerly confined in our country to the tables of the wealthier
classes as long as it was only supplied by our hot-houses, it can now
be enjoyed at a very moderate expense, since thousands are imported by
every West Indian steamer.
The leaves of several species of bromelia furnish excellent twine for
ropes. The inhabitants of the banks of the river San Francisco, in
Brazil, weave their fishing-nets with the fibres of the Caroa (_B.
variegata_), and the filaments of the Crauata de rede (_B. sagenaria_)
furnish a cordage of amazing strength and durability.
The foliage of the screw-pines, so widely extended over the East
Indian and South Sea Isles, where they form a prominent feature in the
landscape, closely resembles that of the bromelias, while the stem
(round which the serrated leaves ascend in spiral convolutions, till
they terminate in a pendulous crown); the aërial roots, and the fruit,
remind one of the palms, the mangroves, and the coniferæ.
The _Pandanus odoratissimus_, or sweet-smelling screw-pine, whose
fruits, when perfectly mature, resemble large rich-coloured
pine-apples, plays an important part in the household economy of the
coral-islanders of the South Sea. The inhabitants of the Mulgrave
Archipelago, where the cocoa-nut is rare, live almost exclusively on
the juicy pulp and the pleasant kernels of the fruit. The dried leaves
serve to thatch their cottages, or are made use of as a material for
mats and raiment. The wood is hard and durable. They string together
the beautiful red and yellow-coloured nuts for ornaments, and wear the
flowers as garlands. When the tree is in full blossom, the air around
is impregnated with a delicious odour.
The grotesque forms of the Cactuses possess the stiff rigidity of the
aloes. Their fleshy stems, covered with a gray-green coriaceous rind,
generally exhibit bunches of hair and thorns instead of leaves. The
angular columns of the Cerei, or torch-cactuses, rise to the height of
sixty feet,--generally branchless, sometimes strangely ramified, as
candelabras, while others creep like ropes upon the ground, or hang,
snake-like, from the trees, on which they are parasitically rooted. The
opuntias are unsymmetrically constructed of thick flat joints springing
one from the other, while the melon-shaped Echinocacti and Mammillariæ,
longitudinally ribbed or covered with warts, remain attached to
the soil. The dimensions of these monstrous plants are exceedingly
variable. One of the Mexican echinocacti (_E. Visnaga_) measures
four feet in height, three in diameter, and weighs about two hundred
pounds; while the dwarf cactus (_E. nana_) is so small that, loosely
rooted in the sand, it frequently remains sticking between the toes
of the dogs that pass over it. The splendidly coloured flowers of the
cactuses form a strange contrast to the deformity of their stems, and
the spectator stands astonished at the glowing life that springs forth
from so unpromising a stock. These strange compounds of ugliness and
beauty are in many respects useful to man. The pulp of the melocacti,
which remains juicy during the driest season of the year, is one of
the vegetable sources of the wilderness, and refreshes the traveller
after he has carefully removed the thorns. Almost all of them bear
an agreeable acid fruit, which, under the name of the Indian fig, is
consumed in large quantities in the West Indies and Mexico. The light
and incorruptible wood is admirably adapted for the construction of
oars and many other implements. The farmer fences his garden with the
prickly opuntias; but the services which they render, as the plants on
which the valuable cochineal insect feeds and multiplies, are far more
important.
The cactuses prefer the most arid situation, naked plains, or slopes,
where they are fully exposed to the burning rays of the sun, and impart
a peculiar physiognomy to a great part of tropical America.
None of the plants belonging to this family existed in the Old World
previously to the discovery of America; but some species have since
then rapidly spread over the warmer regions of our hemisphere. The
Nopal (_Cactus Opuntia_) skirts the Mediterranean along with the
American agave, and from the coasts has even penetrated far into
the interior of Africa, everywhere maintaining its ground, and
conspicuously figuring along with the primitive vegetation of the land.
Although chiefly tropical, the cactuses have a perpendicular range,
which but few other families enjoy. From the low sand-coasts of Peru
and Bolivia they ascend through vales and ravines to the highest ridges
of the Andes. Magnificent dark-brown Peireskias (the only cactus genus
bearing leaves instead of prickles) bloom on the banks of the Lake of
Titicaca, 12,700 feet above the level of the sea; and in the bleak
Puna,[16] even at the very limits of vegetation, the traveller is
astonished at meeting with low bushes of cactuses thickly beset with
yellow prickles.
[Illustration: CEREUS GIGANTEUS.]
What a contrast between these deformities and the delicately
feathered mimosas, unrivalled among the loveliest children of Flora
in the matchless elegance of their foliage! Our common acacias give
but a faint idea of the beauty which these plants attain under the
fostering rays of a tropical sun. In most species the branches
extend horizontally, or umbrella-shaped, somewhat like those of the
Italian pine, and the deep-blue sky shining through the light green
foliage, whose delicacy rivals the finest embroidery, has an extremely
picturesque effect. Endowed with a wonderful sensibility, many of the
mimosas seem, as it were, to have outstepped the bounds of vegetable
life, and to rival in acuteness of feeling the coral polyps and the sea
anemones of the submarine gardens.
[Illustration: MIMOSA.]
Large tracts of country in Brazil are almost entirely covered with
sensitive plants. The tramp of a horse sets the nearest ones in motion,
and, as if by magic, the contraction of the small grey-green leaflets
spreads in quivering circles over the field, making one almost believe,
with Darwin and Dutrochet, that plants have feeling, or tempting one to
exclaim with Wordsworth--
‘It is my faith, that every flower
Enjoys the air it breathes.’
Among the most remarkable forms of tropical vegetation, the creeping
plants, bush-ropes, or lianas (cissus, bauhinia, bignonia, banisteria,
passiflora), that contribute so largely to the impenetrability of the
forests, hold a conspicuous rank. Often three or four bush-ropes, like
strands in a cable, join tree to tree, and branch to branch; others,
descending from on high, take root as soon as their extremity touches
the ground, and appear like shrouds and stays supporting the mainmast
of a line-of-battle ship; while others send out parallel, oblique,
horizontal, and perpendicular shoots in all directions.
No European is able to penetrate the intricate network of a forest
thus matted together: astonished and despairing, he stands before the
dense cordage that impedes his path, and, should he attempt to force
his way through the maze, the strong thorns and hooks with which the
tropical creepers are generally armed would soon make him repent of his
boldness. The Brazilian planter never thinks of entering the forest
without a large knife, or without being accompanied by slaves, who
with heavy scythe-like axes attached to long poles, clear the way by
severing the otherwise impenetrable cordage.
The enormous climbing trees, that stifle the life of the mightiest
giants of the forest, offer a no less wonderful spectacle. At first,
these emblems of ingratitude grow straight upwards like any feeble
shrub, but as soon as they have found a support in other trees, they
begin to extend over their surface; for, while the stems of other
plants generally assume a cylindrical form, these climbers have the
peculiarity of divesting themselves of their rind when brought into
contact with an extraneous body, and of spreading over it, until they
at length enclose it in a tubular mass. When, during this process, the
powers of the original root are weakened, the trunk sends forth new
props to restore the equilibrium; and thus the tough and hardy race
continually acquires fresh strength for the ruin of its neighbours.
[Illustration: POLANARRUA.]
Several species of the fig-tree are peculiarly remarkable for this
distinctive property, and, from the facility with which their seeds
take root where there is a sufficiency of moisture to permit of
germination, are formidable assailants of ancient monuments. Sir
Emerson Tennent mentions one which had fixed itself on the walls of a
ruined edifice at Polanarrua, and formed one of the most remarkable
objects of the place, its roots streaming downwards over the walls as
if their wood had once been fluid, and following every sinuosity of the
building and terraces till they reached the earth.
On the borders of the Rio Guama, Von Martius saw whole groups of
Macauba palms encased in fig-trees that formed thick tubes round
the shafts of the palms, whose noble crowns rose high above them;
and a similar spectacle occurs in India and Ceylon, where the
Tamils look with increased veneration on their sacred pippul thus
united in marriage with the palmyra. After the incarcerated trunk
has been stifled and destroyed, the grotesque form of the parasite,
tubular, cork-screw-like, or otherwise fantastically contorted, and
frequently admitting the light through interstices like loopholes in
a turret, continues to maintain an independent existence among the
straight-stemmed trees of the forest--the image of an eccentric genius
in the midst of a group of sedate citizens.
Like the mosses and lichens of our woods, parasites of endless variety
and almost inconceivable size and luxuriance (ferns, bromelias,
tillandsias, orchids, and pothos) cover in the tropical zone the
trunks and branches of the forest trees, forming hanging gardens, far
more splendid than those of ancient Babylon. While the orchids are
distinguished by the eccentric forms and splendid colouring of their
flowers, sometimes resembling winged insects or birds, the pothos
family (caladium, calla, arum, dracontium, pothos) attract attention
by the beauty of their large, thick-veined, generally arrow-shaped,
digitated, or elongated leaves, and form a beautiful contrast to the
stiff bromelias or the hairy tillandsias that conjointly adorn the
knotty stems and branches of the ancient trees.
In size of leaf, the Pothos family is surpassed by the large tropical
water-plants, the Nymphæas and Nelumbias, among which the Victoria
regia, discovered in 1837 by Robert Schomburgk in the river Berbice,
enjoys the greatest celebrity. The round light-green leaves of this
queen of water-plants measure no less than six feet in diameter, and
are surrounded by an elevated rim several inches high, and exhibiting
the pale, carmine red of the under surface. The odorous white
blossoms, deepening into roseate hues, are composed of several hundred
petals; and, measuring no less than fourteen inches in diameter, rival
the colossal proportions of the leaves. The Victoria is found all over
the Amazon district, but rarely or never in the river itself. It seems
to delight in still waters, growing in inlets, lakes, or very quiet
branches of the river fully exposed to the sun.
[Illustration: BOTTLE-TREE.]
The trunk of several tropical trees offers the remarkable peculiarity
of bulging out in the middle like a barrel. In the Brazilian forests,
the Pao Barrigudo (_Chorisia ventricosa_) arrests the attention of
every traveller by its odd ventricose shape, nearly half as broad in
the centre as long, and gradually tapering towards the bottom and the
top, whence spring a few thin and scanty branches. It is only by seeing
great numbers of these trees all with their character more or less
palpable, that one can believe it is not an accidental circumstance
in the individual tree, instead of being truly characteristic of the
species.
The Delabechea, or bottle-tree, discovered by Mr. Mitchell in tropical
Australia, has the same lumpish mode of growth. Its wood is of so loose
a texture that, when boiling water is poured over its shavings, a clear
jelly is formed, and becomes a thick viscid mass.
In other trees which, struggling upwards to air and light, attain a
prodigious altitude, or from their enormous girth and the colossal
expansion of their branches require steadying from beneath, we find
buttresses projecting like rays from all sides of the trunk. They are
frequently from six to twelve inches thick, and project from five to
fifteen feet, and, as they ascend, gradually sink into the bole and
disappear at the height of from ten to twenty feet from the ground. By
the firm resistance which they offer below, the trees are effectually
protected from the leverage of the crown, by which they would otherwise
be uprooted. Some of these buttresses are so smooth and flat as almost
to resemble sawn planks; as, for instance, in the Bombax Ceiba, one of
the most remarkable examples of this wonderful device of Nature.
[Illustration: SNAKE-TREE.]
In other cases we find the roots fantastically spreading and revelling
in a variety of grotesque shapes, such as we nowhere find in the less
exuberant vegetation of Europe. Thus, in the india-rubber tree (_Ficus
elastica_), masses of the roots appear above ground, extending on
all sides from the base, and writhing over the surface in serpentine
undulations, so that the Indian villagers give it the name of the
snake-tree. Sir Emerson Tennent mentions an avenue of these trees
leading to the botanical garden of Peradenia, in Ceylon, the roots
of which meet from either side of the road, and have so covered the
surface as to form a wooden framework, the interstices of which retain
the materials that form the roadway. These tangled roots sometimes
trail to such an extent that they have been found upwards of 140 feet
in length, whilst the tree itself was not thirty feet high.
The roots of the Mangroves, which in the tropical zone are found
fringing the shores of the sea, or the mouths of rivers, wherever the
reflux of the tide exposes a broad belt of alluvial soil, are admirably
adapted for securing a footing on the unstable brink of the ocean.
[Illustration: MANGROVE.]
The growth of these salt-water-loving trees (_Rhizophora gymnorrhiza_,
_R. Mangle_) is equally peculiar and picturesque. The seeds germinate
on the branches, and, increasing to a considerable length, finally fall
down into the mud, where they stick, with their sharp point buried, and
soon take root.
As the young mangrove grows upwards, pendulous roots issue from the
trunk and low branches, and ultimately strike into the muddy ground,
where they increase to the thickness of a man’s leg; so that the whole
has the appearance of a complicated series of loops and arches, from
five to ten feet high, supporting the body of the tree like so many
artificial stakes.
It may easily be imagined what dense and inextricable thickets, what
incomparable breakwaters, plants like these--through whose mazes even
the light-footed Indian can only penetrate by stepping from root to
root--are capable of forming.
Their influence in promoting the growth of land is very great, and in
course of time they advance over the shallow borders of the ocean.
Their matted roots stem the flow of the waters, and, retaining the
earthy particles that sink to the bottom between them, gradually raise
the level of the soil. As the new formation progresses, thousands of
seeds begin to germinate upon its muddy foundation, thousands of cables
descend, still farther to consolidate it; and thus foot by foot, year
after year, the mangroves extend their empire and encroach upon the
maritime domains.
The enormous deltas of many tropical rivers partly owe their immense
development to the unceasing expansion of these littoral woods; and
their influence should by no means be overlooked by the geologist when
describing the ancient and eternal strife between land and ocean.
When the waters retire from under the tangled arcades of the mangroves,
the black mud, which forms the congenial soil of these plants, appears
teeming with a boundless variety of life. It absolutely swarms with
the lower marine animals, with myriads of holothurias, annelides,
sea-urchins, entomostraca, paguri, and crabs, whose often brilliantly
coloured carapaces form a strong contrast to the black ooze in which
they are seen to crawl about. Life clings even to the roots and
branches bathed by the rising floods; for they are found covered with
muscles, barnacles, and oysters, which thus have the appearance of
growing upon trees, and pass one-half of their existence under water,
the other in the sultry atmosphere of a tropical shore.
The close-eyed Gudgeon (_Periophthalmus_), or ‘Jumping Johnny,’ as
he is more familiarly named by the sailors, plays a conspicuous part
in the animal world of the mangrove swamps, where the uncouth form
of this strange amphibious fish may be seen jumping about in the mud
like a frog, or sliding awkwardly along on its belly with a gliding
motion. By means of its pectoral fins, it is even enabled to climb
with great facility among the roots of the mangroves, where it finds a
goodly harvest of minute crustaceans. It must, however, not be supposed
that ‘Johnny’ has all the swamp to himself; for though he manages to
swallow many a victim, he is not seldom doomed to become the prey of
creatures more wily or stronger than himself. A large and powerful crab
of the Grapsus family may often be observed stealing, with an almost
imperceptible motion, and in a cautious, sidelong manner, towards a
gudgeon basking on the shore, and, before the fish has time to plunge
into the sea, the pincer of the crab secures it in a vice-like gripe,
from which it is perfectly hopeless to escape.
‘Johnny’ is a pugnacious little fellow, and rather prolonged fights
may be observed between him and his brethren. At the mouth of the
Zambesi, Dr. Livingstone saw one which, in fleeing from an apparent
danger, jumped into a pool a foot square, which another evidently
regarded as his by prior discovery. In a twinkling the owner, with eyes
flashing fury, and with dorsal fin bristling up in a rage, dashed at
the intruding foe. The fight waxed furious. No tempest in a teapot ever
equalled the storm of that miniature sea. The warriors were now in the
water and anon out of it, for the battle raged on sea and shore. They
struck hard, they bit each other, until becoming exhausted, they seized
each other by the jaws like two bull-dogs. They paused for breath, and
were at it again as fiercely as before, until the combat ended by the
precipitate retreat of the invader.
The vast multitude of marine animals which peoples the mangrove swamps
naturally attracts a great number of strand, lacustrine, and sea birds;
for it would be strange, indeed, if guests were wanting where the table
is so prodigally supplied. The red ibis, the snow-white egrette, the
rosy spoonbill, the tall flamingo, and an abundance of herons and other
water-fowl, love to frequent the mangrove thickets, enhancing by their
magnificent plumage the beauty of the scene. For, however repulsive may
be the swampy ground on which these strange trees delight, yet their
bright green foliage, growing in radiated tufts at the ends of the
branches, and frequently bespangled with large gaily-coloured flowers,
affords a most pleasing spectacle. Many an interesting discovery would
here, no doubt, reward the naturalist’s attention; but the mangroves
know well how to keep their secrets, and to repel the curiosity of
man. Should he attempt to invade their domains, clouds of bloodthirsty
insects would instantly make him repent of his temerity; for the plague
of the mosquitoes is nowhere more dreadful than in the thickets of the
semi-aquatic Rhizophoræ. And supposing his scientific zeal intense
enough to bid defiance to the torture of their stings, and to scorn
the attacks of every other visible foe--insect or serpent, crocodile
or beast of prey--that may be lurking among the mangroves, yet the
reflection may well bid him pause, that poisonous vapours, pregnant
with cholera or yellow fever, are constantly rising from that muddy
soil. Even in the temperate regions of Europe the emanations from
marshy grounds are pregnant with disease, but the malaria ascending
from the sultry morasses of the torrid zone is absolutely deadly.
Thus there cannot possibly be a better natural bulwark for a land
than to be belted with mangroves; and if Borneo, Madagascar, Celebes,
and many other tropical islands and coasts, have to the present day
remained free from the European yoke, they are principally indebted for
their independence to the miasms and tangles of a Rhizophora girdle,
bidding defiance alike to the sharp edge of the axe or the destructive
agency of fire.
As the mangroves are found in places suited to their growth throughout
the whole torrid zone, it is not surprising that there are many
species, some rising to the height of stately trees, while others are
content with a shrub-like growth. Some are peculiar to America, others
to the Old World; some grow near the sea, others prefer a brackish
water and the low swampy banks of rivers.
The Jriarteas and Screw-pines are as singular as the mangroves in
the formation of their roots; but those of the Lum, a large tree
which Kittlitz found growing on the island of Ualan, are perhaps
without a parallel in the vegetable world. Each of the roots,
running above-ground for a considerable distance, is surmounted by a
perfectly vertical crest, gradually diminishing in size as the root
recedes from the trunk, but often three, or even four, feet high near
its base. These crests, which are very thin but perfectly smooth,
regularly follow all the sinuosities of the root, and thus form, for
a considerable distance round the tree, a labyrinth of the strangest
appearance. Large spaces of swampy ground are often covered with their
windings, and it is no easy matter to walk on the sharp edges of these
vertical bands, whose interstices are generally filled with deep mud.
On being struck, the larger crests emit a deep sonorous sound, like
that of a kettledrum.
The thorns and spines with which many European plants are armed,
give but a faint idea of the size which these defensive weapons
attain in the tropical zone. The cactuses, the acacias, and many
of the palm-trees, bristle with sharp-pointed shafts, affording
ample protection against the attacks of hungry animals, and might
appropriately be called vegetable hedge-hogs, or porcupines. The
Toddalia aculeata, a climbing plant, very common in the hill-jungles
of Ceylon, is thickly studded with knobs, about half an inch high, and
from the extremity of each a thorn protrudes, as large and sharp as the
bill of a sparrow-hawk.
The black twigs of the buffalo-thorn (_Acacia latronùm_), a low shrub
abounding in northern Ceylon, are beset at every joint by a pair of
thorns set opposite each other, like the horns of an ox, as sharp as
a needle, from two to three inches in length, and thicker at the base
than the stem they grow on; and the Acacia tomentosa, another member
of the same numerous genus, has thorns so large as to be called the
jungle-nail by Europeans, and the elephant-thorn by the natives. In
some of these thorny plants, the spines grow, not singly, but in
branching clusters, each point presenting a spike as sharp as a lancet;
and where these shrubs abound, they render the forest absolutely
impassable, even to animals of the greatest size and strength.
The formidable thorny plants of the torrid zone, which are often made
use of by man to protect his fields and plantations against wild beasts
and robbers, have sometimes even been made to serve as a bulwark
against hostile invasions. Thus Sir Emerson Tennent informs us, that,
during the existence of the Kandyan kingdom, before its conquest by
the British, the frontier forests were so thickened and defended by
dense plantations of thorny plants as to form a natural fortification
impregnable to the feeble tribes on the other side; and at each pass
which led to the level country, movable gates, formed of the
same thorny beams, were suspended as an ample security against the
incursions of the naked and timid lowlanders.
[Illustration: THE LUM TREE.]
Poets and moralists, judging by what they see in England, have
concluded that fruits of a small size, whose fall cannot be dangerous
to man, invariably grow on high trees, while large fruits, such as
the pumpkin, are only found trailing on the ground. But a visit to
the tropics would soon convince them of their error, for two of the
largest and heaviest fruits known, the Brazilian nut (_Bertholletia_)
and the Durian of the Indian Archipelago, grow on high forest trees,
from which they fall down when ripe, and frequently wound or kill the
natives. ‘From this,’ says Mr. Wallace, ‘we can learn two things--in
the first place, not to draw general conclusions from a locally very
limited knowledge of nature, and, secondly, that trees and fruits, as
well as the manifold productions of the animal kingdom, have not been
exclusively organised with a reference to man.’
[Illustration: A CEYLONESE COCOA-NUT OIL-MILL.]