ASPECTS OF NATURE,
IN
DIFFERENT LANDS AND DIFFERENT CLIMATES;
WITH
Scientific Elucidations.
BY
ALEXANDER VON HUMBOLDT.
TRANSLATED BY MRS. SABINE.
IN TWO VOLUMES.
VOL. II.
LONDON:
PRINTED FOR
LONGMAN, BROWN, GREEN, AND LONGMANS,
PATERNOSTER ROW; AND
JOHN MURRAY, ALBEMARLE STREET.
1849.
Wilson and Ogilvy, Skinner Street, Snowhill, London.
CONTENTS OF VOL. II.
PAGE
PHYSIOGNOMY OF PLANTS 3
Annotations and Additions 33
Postscript on the Physiognomic Classification of Plants 205
ON THE STRUCTURE AND MODE OF ACTION OF VOLCANOS, IN DIFFERENT
PARTS OF THE GLOBE 214
Annotations and Additions 243
THE VITAL FORCE, OR THE RHODIAN GENIUS 251
Note 259
THE PLATEAU OF CAXAMARCA, THE ANCIENT CAPITAL OF THE INCA
ATAHUALLPA, and the First View of the Pacific Ocean, from the
Crest of the Andes 267
Annotations and Additions 303
General Summary of the CONTENTS of the Second Volume 327
INDEX 341
ASPECTS OF NATURE
IN
DIFFERENT LANDS AND DIFFERENT CLIMATES.
PHYSIOGNOMY OF PLANTS.
When the active curiosity of man is engaged in interrogating Nature,
or when his imagination dwells on the wide fields of organic creation,
among the multifarious impressions which his mind receives, perhaps
none is so strong and profound as that of the universal profusion
with which life is everywhere distributed. Even on the polar ice the
air resounds with the cries or songs of birds, and with the hum of
insects. Nor is it only the lower dense and vaporous strata of the
atmosphere which are thus filled with life, but also the higher and
more ethereal regions. Whenever Mont Blanc or the summits of the
Cordilleras have been ascended, living creatures have been found there.
On the Chimborazo,[1] eight thousand feet higher than Etna, we found
butterflies and other winged insects, borne by ascending currents of
air to those almost unapproachable solitudes, which man, led by a
restless curiosity or unappeasable thirst of knowledge, treads with
adventurous but cautious steps: like him strangers in those elevated
regions, their presence shows us that the more flexible organization of
animal creation can subsist far beyond the limits at which vegetation
ceases. The condor,[2] the giant of the Vulture tribe, often soared
over our heads above all the summits of the Andes, at an altitude
higher than would be the Peak of Teneriffe if piled on the snow-covered
crests of the Pyrenees. The rapacity of this powerful bird attracts him
to these regions, whence his far-seeing eye may discern the objects
of his pursuit, the soft-wooled Vicunas, which, wandering in herds,
frequent, like the Chamois, the mountain pastures adjacent to the
regions of perpetual snow.
But if the unassisted eye sees life distributed throughout the
atmosphere, when armed with the microscope we discover far other
marvels. Rotiferæ, Brachionæ, and a multitude of microscopic
animalculæ, are carried up by the winds from the surface of evaporating
waters. These minute creatures, motionless and apparently dead, are
borne to and fro in the air until the falling dews bring them back to
the surface of the earth, dissolve the film or envelope which encloses
their transparent rotating bodies,[3] and, probably by means of the
oxygen which all waters contain, breathe new irritability into their
dormant organs.
According to Ehrenberg’s brilliant discovery, the yellow sand or dust
which falls like rain on the Atlantic near the Cape de Verde Islands,
and is occasionally carried even to Italy and Middle Europe, consists
of a multitude of siliceous-shelled microscopic animals. Perhaps
many of them float for years in the upper strata of the atmosphere,
until they are brought down by vertical currents or in accompaniment
with the superior current of the trade-winds, still susceptible of
revivification, and multiplying their species by spontaneous division
in conformity with the particular laws of their organisation.
But, besides creatures fully formed, the atmosphere contains
innumerable germs of future life, such as the eggs of insects and the
seeds of plants, the latter provided with light hairy or feathery
appendages, by means of which they are wafted through the air during
long autumnal wanderings. Even the fertilizing dust or pollen from
the anthers of the male flowers, in species in which the sexes are
separated, is carried over land and sea, by winds and by the agency of
winged insects,[4] to the solitary female plant on other shores. Thus
wherever the glance of the inquirer into Nature penetrates, he sees the
continual dissemination of life, either fully formed or in the germ.
If the aereal ocean in which we are submerged, and above the surface of
which we cannot rise, be indispensable to the existence of organised
beings, they also require a more substantial aliment, which they can
find only at the bottom of this gaseous ocean. This bottom is of two
kinds; the smaller portion consisting of dry land in immediate contact
with the external atmosphere, and the larger portion consisting of
water, which may perhaps have been formed thousands of years ago by
electric agencies from gaseous substances, and which is now incessantly
undergoing decomposition in the laboratories of Nature, in the clouds
and in the pulsating vessels of animals and plants. Organic forms also
descend deep below the surface of the earth, wherever rain or surface
water can percolate either by natural cavities or by mines or other
excavations made by man: the subterranean cryptogamic Flora was an
object of my scientific research in the early part of my life. Thermal
springs of very high temperature nourish small Hydropores, Confervæ,
and Oscillatoria. At Bear Lake, near the Arctic Circle, Richardson saw
the ground, which continues frozen throughout the summer at a depth of
twenty inches, covered with flowering plants.
We do not yet know where life is most abundant,--whether on continents
or in the unfathomed depths of the ocean. Through the excellent work of
Ehrenberg, “Über das Verhalten des kleinsten Lebens,” we have seen the
sphere of organic life extend, and its horizon widen before our eyes,
both in the tropical parts of the ocean and in the fixed or floating
masses of ice of the Antarctic seas. Siliceous-shelled Polygastrica,
and even Coscinodiscæ, with their green ovaries, have been found alive
enveloped in masses of ice only twelve degrees from the Pole; the small
black Glacier flea (Desoria glacialis) and Podurellæ inhabit the narrow
tubular holes examined by Agassiz in the Swiss glaciers. Ehrenberg has
shown that on several microscopic Infusoria (Synedra, Cocconeis) others
live as parasites, and that in the Gallionellæ such is their prodigious
power of development, or capability of division, that in the space of
four days an animalcule invisible to the naked eye can form two cubic
feet of the Bilin polishing slate. In the sea, gelatinous worms, living
or dead, shine like stars,[5] and by their phosphoric light change
the surface of the wide ocean into a sea of fire. Ineffaceable is the
impression made on my mind by the calm nights of the torrid zone, on
the waters of the Pacific. I still see the dark azure of the firmament,
the constellation of the Ship near the zenith, and that of the Cross
declining towards the horizon, shedding through the perfumed air their
soft and planetary lustre; while bright furrows of flashing light
marked the track of the dolphins through the midst of the foaming waves.
Not only the ocean, but also the waters of our marshes, hide from us
an innumerable multitude of strange forms. The naked eye can with
difficulty distinguish the Cyclidias, the Euglenes, and the host of
Naids divisible by branches like the Lemna or Duckweed, of which
they seek the shade. Other creatures inhabit receptacles where the
light cannot penetrate, and an atmosphere variously composed, but
differing from that which we breathe: such are the spotted Ascaris,
which lives beneath the skin of the earthworm; the Leucophra, of
a bright silvery colour, in the interior of the shore Naid; and a
Pentastoma, which inhabits the large pulmonary cells of the rattlesnake
of the tropics.[6] There are animalculæ in the blood of frogs and of
salmon, and even, according to Nordmann, in the fluids of the eyes of
fishes and in the gills of the Bleak. Thus the most hidden recesses
of creation teem with life. We propose in these pages to direct our
attention to the vegetable world, on the existence of which that of
animals is dependent. Plants are incessantly engaged in disposing
into order towards subsequent organization the raw materials of which
the earth is composed: it is their office, by their vital forces or
powers, to prepare those substances which, after undergoing a thousand
modifications, are gradually converted to nobler purposes in the
formation of nervous tissues. In directing our consideration towards
the various families of plants, we shall at the same time glance at
the multitude of animated beings to which they afford nutriment and
protection.
The carpet of flowers and of verdure spread over the naked crust of
our planet is unequally woven; it is thicker where the sun rises high
in the ever cloudless heavens, and thinner towards the poles, in the
less happy climes where returning frosts often destroy the opening
buds of spring, or the ripening fruits of autumn. Everywhere, however,
man finds some plants to minister to his support and enjoyment. If
new lands are formed, the organic forces are ever ready to cover the
naked rock with life. Sometimes, as at an early period among the
Greek Islands, volcanic forces suddenly elevate above the surface
of the boiling waves a rock covered with Scoriæ: sometimes, by a
long-continued and more tranquil series of phenomena, the collective
labours of united Lithophytes[7] raise their cellular dwellings on the
crests of submarine mountains, until, after thousands of years, the
structure reaches the level of the ocean, when the creatures which have
formed it die, leaving a low flat coral island. How are the seeds of
plants brought so immediately to these new shores? by wandering birds,
or by the winds and waves of the ocean? The distance from other coasts
makes it difficult to determine this question; but, no sooner is the
rock of the newly raised islands in direct contact with the atmosphere,
than there is formed on its surface, in our northern countries, a
soft silky net-work, appearing to the naked eye as coloured spots and
patches. Some of these patches are bordered by single or double raised
lines running round their margins; other patches are crossed by similar
lines traversing them in various directions. Gradually the light colour
of the patches becomes darker, the bright yellow which was visible
at a distance changes to brown, and the bluish gray of the Leprarias
becomes a dusty black. The edges of neighbouring patches approach and
run into each other; and on the dark ground thus formed there appear
other lichens, of a circular shape and dazzling whiteness. Thus an
organic film or covering establishes itself by successive layers; and
as mankind, in forming settled communities, pass through different
stages of civilisation, so is the gradual propagation and extension
of plants connected with determinate physical laws. Lichens form the
first covering of the naked rock, where afterwards lofty forest trees
rear their airy summits. The successive growth of mosses, grasses,
herbaceous plants, and shrubs or bushes, occupies the intervening
period of long but undetermined duration. The part which lichens and
mosses perform in the northern countries is effected within the tropics
by Portulacas, Gomphrenas, and other low and succulent shore plants.
The history of the vegetable covering of our planet, and its gradual
propagation over the desert crust of the earth, has its epochs, as
well as that of the migrations of the animal world.
Yet although organic life is everywhere diffused, and the organic
powers are incessantly at work in reconnecting with each other the
elements set free by death or dissolution, the abundance and variety
of organised beings, and the rapidity with which they are renewed,
differ in different climates. In the cold zones, the activity of
organic life undergoes a temporary suspension during a portion of the
year by frost; fluidity is an essential condition of life or vital
action, and animals and plants, with the exception of mosses and other
cryptogamia, are in those regions buried for several months of each
year in winter sleep. Over a large part of the earth, therefore, there
could only be developed organic forms capable of supporting either
a considerable diminution of heat, or, being without leaves, a long
interruption of the vital functions. Thus we see variety and grace of
form, mixture of colours, and generally the perpetually youthful energy
and vigour of organic life, increase as we approach the tropics. This
increase can be denied only by those who have never quitted Europe, or
who have neglected the study of physical geography. When, leaving our
oak forests, we traverse the Alps or the Pyrenees, and enter Italy or
Spain, or when we direct our attention to some of the African shores
of the Mediterranean, we might easily be led to draw the erroneous
inference that hot countries are marked by the absence of trees. But
those who do so, forget that the South of Europe wore a different
aspect on the first arrival of Pelasgian or Carthaginian colonies; they
forget that an ancient civilisation causes the forests to recede more
and more, and that the wants and restless activity of large communities
of men gradually despoil the face of the earth of the refreshing
shades which still rejoice the eye in Northern and Middle Europe, and
which, even more than any historic documents, prove the recent date
and youthful age of our civilization. The great catastrophe which
occasioned the formation of the Mediterranean, when the swollen waters
of what was previously an immense lake burst through the barriers
of the Dardanelles and of the Pillars of Hercules, appears to have
stripped the adjacent countries of a large portion of their coating of
vegetable mould. The traditions of Samothrace,[8] handed down to us
by Grecian writers, appear to indicate the recentness of the epoch of
the ravages caused by this great change. In all the countries which
surround the Mediterranean, and which are characterised by beds of the
tertiary and cretaceous periods (nummulitic limestone and neocomian
rocks), great part of the surface of the earth consists of naked rock.
One especial cause of the picturesque beauty of Italian scenery is the
contrast thus afforded between the bare rock, and the islands if I
may so call them of luxuriant vegetation scattered over its surface.
Wherever the rock is less intersected with fissures, so that it retains
water at the surface, and where it is covered with vegetable mould,
there, as on the enchanting shores of the Lake of Albano, Italy has her
oak forests, with glades as deeply embowered and verdure as fresh as
those which we admire in the North of Europe.
The deserts to the south of the Atlas, and the immense plains or
steppes of South America, must be regarded as only local phenomena. The
latter, the South American steppes, are clothed, in the rainy season
at least, with grass, and with low-growing almost herbaceous mimosas.
The African deserts are, indeed, at all seasons devoid of vegetation;
seas of sand, surrounded by forest shores clothed with perpetual
verdure. A few scattered fan-palms alone recall to the wanderer’s
recollection that these awful solitudes belong to the domain of the
same animated terrestrial creation which is elsewhere so rich and so
varied. The fantastic play of the mirage, occasioned by the effects of
radiant heat, sometimes causes these palm trees to appear divided from
the ground and hovering above its surface, and sometimes shews their
inverted image reflected in strata of air undulating like the waves of
the sea. On the west of the great Peruvian chain of the Andes, on the
coasts of the Pacific, I have passed entire weeks in traversing similar
deserts destitute of water.
The origin of extensive arid tracts destitute of plants, in the midst
of countries rich in luxuriant vegetation, is a geognostical problem
which has hitherto been but little considered, but which has doubtless
depended on ancient revolutions of nature, such as inundations or great
volcanic changes. When once a region has lost the covering of plants
with which it was invested, if the sands are loose and mobile and are
destitute of springs, and if the heated atmosphere, forming constantly
ascending currents, prevents precipitation taking place from clouds[9],
thousands of years may elapse ere organic life can pass from the
verdant shores to the interior of the sandy sea, and repossess itself
of the domain from which it had been banished.
Those, therefore, who can view nature with a comprehensive glance and
apart from local phenomena, may see from the poles to the equator
organic life and vigour gradually augment with the augmentation of
vivifying heat. But, in the course of this progressive increase there
are reserved to each zone its own peculiar beauties; to the tropics,
variety and grandeur of vegetable forms; to the north, the aspect of
its meadows and green pastures, and the periodic reawakening of nature
at the first breath of the mild air of spring. Each zone, besides its
own peculiar advantages, has its own distinctive character. Primeval
laws of organisation, notwithstanding a certain degree of freedom in
the abnormal development of single parts, bind all animal and vegetable
forms to fixed ever-recurring types. As we recognise in distinct
organic beings a determinate physiognomy, and as descriptive botany and
zoology, in the restricted sense of the terms, consist in a detailed
analysis of animal and vegetable forms, so each region of the earth
has a natural physiognomy peculiar to itself. The idea indicated by
the painter by expressions such as “Swiss nature,” “Italian sky,” &c.,
rests on a partial perception of this local character in the aspect
of nature. The azure of the sky, the lights and shadows, the haze
resting on the distance, the forms of animals, the succulency of the
plants and herbage, the brightness of the foliage, the outline of
the mountains, are all elements which determine the total impression
characteristic of each district or region. It is true that in every
zone the same kinds of rocks, trachyte, basalt, porphyritic schists,
and dolomite, form groups having the same physiognomy and aspect.
The greenstone precipices of South America and Mexico resemble those
of the Fichtel-Gebirge of Germany, just as among animals the form of
the Allco, or native race of dogs of the New Continent, corresponds
perfectly with that of the European race. For the inorganic crust of
the globe shews itself independent of climatic influences; whether it
be that differences of climate depending on differences of latitude
were more recent than the formation of the rocks, or that the mass
of the earth in solidifying and parting with its heat regulated its
own temperature,[10] instead of receiving it from without. Thus all
the kinds of rock with which we are acquainted may be met with in all
parts of the globe, and everywhere affect the same characteristic
forms. Everywhere basalt rises in twin mountains and truncated cones;
everywhere the porphyritic trap appears in grotesquely arranged masses,
and granite in rounded summits. Also similar forms of trees--pines
and oaks--adorn the declivities of the mountains of Sweden, and
those of the most southern part of Mexico.[11] Yet, notwithstanding
these correspondences of form, and this similarity of outline in the
component parts of the picture, their grouping gives to the whole the
greatest difference of character.
Mineralogy is not more distinct from geology than is the individual
description of natural objects from a general description of the
physiognomy of nature. George Forster, in the narrative of his voyages,
and in his other publications,--Goethe, in the descriptions of nature
which so many of his immortal works contain,--Buffon, Bernardin de
St. Pierre, and Chateaubriand, have traced with inimitable truth of
description the character of some of the zones into which the earth
is divided. Not only do such descriptions afford us mental enjoyment
of a high order, but the knowledge of the character which nature
assumes in different regions is moreover intimately connected with the
history of man, and of his civilisation. For although the commencement
of this civilisation is not solely determined by physical relations,
yet the direction which it takes, the national character, and the
more grave or gay dispositions of men, are dependent in a very high
degree on climatic influences. How powerfully have the skies of Greece
acted on its inhabitants! The nations settled in the fair and happy
regions bounded by the Euphrates, the Halys, and the Egean Sea, also
early attained amenity of manners and delicacy of sentiment. When in
the middle ages religious enthusiasm suddenly re-opened the sacred
East to the nations of Europe who were sinking back into barbarism,
our ancestors in returning to their homes brought with them gentler
manners, acquired in those delightful valleys. The poetry of the
Greeks, and the ruder songs of the primitive northern nations, owe
great part of their peculiar character to the aspect of the plants and
animals seen by the bard, to the mountains and valleys which surrounded
him, and to the air which he breathed. And to recall more familiar
objects, who does not feel himself differently affected in the dark
shade of the beech, on hills crowned with scattered fir-trees, or on
the turfy pasture, where the wind rustles in the trembling foliage
of the birch? These trees of our native land have often suggested or
recalled to our minds images and thoughts, either of a melancholy, of a
grave and elevating, or of a cheerful character. The influence of the
physical on the moral world,--that reciprocal and mysterious action
and reaction of the material and the immaterial,--gives to the study
of nature, when regarded from higher points of view, a peculiar charm,
still too little recognised.
But if the characteristic aspect of different portions of the earth’s
surface depends conjointly on all external phenomena,--if the contours
of the mountains, the physiognomy of plants and animals, the azure
of the sky, the form of the clouds, and the transparency of the
atmosphere, all combine in forming that general impression which is
the result of the whole, yet it cannot be denied that the vegetable
covering with which the whole earth is adorned is the principal
element in the impression. Animal forms are deficient in mass, and the
individual power of motion which animals possess, as well as often the
smallness of their size, withdraw them from our sight. The vegetable
forms, on the contrary, produce a greater effect by their magnitude
and by their constant presence. The age of trees is marked by their
size, and the union of age with the manifestation of constantly renewed
vigour is a charm peculiar to the vegetable kingdom. The gigantic
Dragon-tree of Orotava,[12] (as sacred in the eyes of the inhabitants
of the Canaries as the olive-tree in the Citadel of Athens, or the
Elm of Ephesus), the diameter of which I found, when I visited those
Islands, to be more than 16 feet, had the same colossal size, when the
French adventurers, the Béthencourts, conquered these gardens of the
Hesperides in the beginning of the fifteenth century; yet it still
flourishes, as if in perpetual youth, bearing flowers and fruit. A
tropical forest of Hymenæas and Cæsalpinieæ may perhaps present to us a
monument of more than a thousand years’ standing.
If we embrace in one general view the different species of phænogamous
plants at present contained in herbariums, the number of which may
now be estimated at considerably above 80000,[13] we shall recognise
in this prodigious multitude certain leading forms to which many
others may be referred. In determining these leading forms or types,
on the individual beauty, the distribution, and the grouping of which
the physiognomy of the vegetation of a country depends, we must not
follow the march of systems of botany, in which from other motives
the parts chiefly regarded are the smaller organs of propagation, the
flowers and the fruit; we must, on the contrary, consider solely that
which by its mass stamps a peculiar character on the total impression
produced, or on the aspect of the country. Among the leading forms of
vegetation to which I allude, there are, indeed, some which coincide
with families belonging to the “natural systems” of botanists. Such are
the forms of Bananas, Palms, Casuarineæ, and Coniferæ. But the botanic
systematist divides many groups which the physiognomist is obliged to
unite. When plants or trees present themselves in masses, the outlines
and distribution of the leaves and the form of the stems and of the
branches are blended together. The painter (and here the artist’s
delicate tact and appreciation of nature are demanded) can distinguish
in the middle distance and background of a landscape groves of palms or
pines from beech woods, but he cannot distinguish the latter from woods
consisting of other deciduous forest trees.
Above sixteen different forms of vegetation are principally concerned
in determining the aspect or physiognomy of Nature. I mention only
those which I have observed in the course of my travels both in the
New and Old Continents, where during many years I have attentively
examined the vegetation of the regions comprised between the 60th
degree of North and the 12th degree of South latitude. The number of
these forms will no doubt be considerably augmented when travellers
shall have penetrated farther into the interior of Continents, and
discovered new genera of plants. In the South-eastern part of Asia,
the interior of Africa and of New Holland, and in South America from
the river of the Amazons to the province of Chiquitos, the vegetation
is still entirely unknown to us. How if at some future time a country
should be discovered in which ligneous fungi, Cenomyce rangiferina,
or mosses, should form tall trees? The Neckera dendroides, a German
species of moss, is in fact arborescent; and bamboos (which are
arborescent grasses) and the tree ferns of the tropics, which are often
higher than our lime-trees and alders, now present to the European a
sight as surprising as would be that of a forest of tree mosses to its
discoverer. The absolute size and the degree of development attained by
organic forms of the same family (whether plants or animals), depend
on laws which are still unknown to us. In each of the great divisions
of the animal kingdom, insects, crustacea, reptiles, birds, fishes,
or mammalia, the size of the body oscillates between certain extreme
limits. But these limits, which have been established by observation as
far as it has yet gone, may be corrected by the discovery of species
with which we are still unacquainted.
In land animals the higher temperatures of the low latitudes appear
to have favoured organic development. The small and slender form of
our lizards is exchanged in the south for the gigantic, heavy, and
cuirassed bodies of crocodiles. In the formidable tiger, lion, and
jaguar, we see repeated, on a larger scale, the form of the common
cat, one of the smallest of our domestic animals. If we penetrate
into the interior of the earth, and search the cemeteries in which
the plants and animals of the ancient world lie entombed, the fossil
remains which we discover not only announce a distribution inconsistent
with our present climates,--they also disclose to us gigantic forms
that contrast no less with those which now surround us, than does the
simple heroism of the Greeks with the character of human greatness in
modern times. Has the temperature of our planet undergone considerable
changes,--possibly of periodical recurrence? If the proportion
between land and sea, and even the height of the aerial ocean and
its pressure,[14] have not always been the same, the physiognomy
of nature, and the dimensions and forms of organised beings, must
also have been subjected to various alterations. Huge Pachydermata,
Mastodons, Owen’s Mylodon robustus, and the Colossochelys, a
land-tortoise above six feet high, have existed, and in the vegetable
kingdom there have been forests composed of gigantic Lepidodendra,
cactus-like Stigmarias, and numerous kinds of Cycadeæ. Unable to
depict fully according to its present features the physiognomy of
our planet in this its later age, I will only venture to attempt to
indicate the characters which principally distinguish those vegetable
groups which appear to me to be most strongly marked by physiognomic
differences. However favoured by the richness and flexibility of our
native language, it is still an arduous and hazardous undertaking
when we attempt to trace in words that which belongs rather to the
imitative art of the painter. I feel also the necessity of avoiding as
much as possible the wearisome impression almost inseparable from all
lengthened enumerations.
We will begin with palms,[15] the loftiest and noblest of all vegetable
forms, that to which the prize of beauty has been assigned by the
concurrent voice of nations in all ages; for the earliest civilisation
of mankind belonged to countries bordering on the region of palms,
and to parts of Asia where they abound. Their lofty, slender, ringed,
and, in some cases, prickly stems, terminate in aspiring and shining
either fanlike or pinnated foliage. The leaves are frequently curled,
like those of some gramineæ. Smooth polished stems of palms carefully
measured by me had attained 192 English feet in height. In receding
from the equator and approaching the temperate zone, palms diminish in
height and beauty. The indigenous vegetation of Europe only comprises a
single representative of this form of plants, the sea-coast Dwarf-palm
or Chamærops, which, in Spain and Italy, extends as far north as the
44th parallel of latitude. The true climate of palms has a mean annual
temperature of 20°.5-22° Reaumur (78°.2-81°.5 Fahr). The Date, which
is much inferior in beauty to several other genera, has been brought
from Africa to the south of Europe, where it lives, but can scarcely be
said to flourish, in a mean temperature not exceeding 12°-13°.5 Reaumur
(59°-62°.4 Fahr). Stems of palms and fossil bones of elephants are
found buried beneath the surface of the earth in northern countries, in
positions which make it appear probable that their presence is not to
be accounted for by their having been drifted thither from the tropics,
and we are led to infer that in the course of the great revolutions
which our planet has undergone, great changes of climate, and of the
physiognomy of nature as dependent on climate, have taken place.
In all parts of the globe the palm form is accompanied by that of
Plantains or Bananas; the Scitamineæ and Musaceæ of botanists,
Heliconia, Amomum, and Strelitzia. In this form, the stems, which are
low, succulent, and almost herbaceous, are surmounted by long, silky,
delicately-veined leaves of a thin loose texture, and bright and
beautiful verdure. Groves of plantains and bananas form the ornament
of moist places in the equatorial regions. It is on their fruits
that the subsistence of a large part of the inhabitants of the torrid
zone chiefly depends, and, like the farinaceous cereals of the north,
they have followed man from the infancy of his civilisation[16]. The
aboriginal site of this nutritious plant is placed by some Asiatic
fables or traditions on the banks of the Euphrates, and by others, with
more probability, at the foot of the Himalaya. Grecian fables named
the fields of Enna as the happy native land of the cereals; and if in
northern climes, where corn is cultivated in immense unbroken fields,
their monotonous aspect adds but little to the beauty of the landscape,
the inhabitant of the tropics, on the other hand, in rearing groves
of plantains wherever he fixes his habitation, contributes to the
adornment of the earth’s surface by the extension of one of the most
noble and beautiful forms of the vegetable world.
The form of Malvaceæ[17] and Bombaceæ, represented by Ceiba,
Cavanillesia, and the Mexican hand-tree Cheirostemon, has enormously
thick trunks; large, soft, woolly leaves, either heart-shaped or
indented; and superb flowers frequently of a purple or crimson hue.
It is to this group of plants that the Baobab, or monkey bread-tree,
(Adansonia digitata), belongs, which, with a very moderate elevation,
has a diameter of 32 English feet, and is probably the largest and most
ancient organic monument on our planet. In Italy the Malvaceæ already
begin to impart to the vegetation a peculiar southern character.
The delicately pinnated foliage of the Mimosa form[18], of which
Acacia, Desmanthus, Gleditschia, Porleria, and Tamarindus are
important members, is entirely wanting in our temperate zone in the old
continent, though found in the United States, where, in corresponding
latitudes, vegetation is more varied and more vigorous than in Europe.
The umbrella-like arrangement of the branches, resembling that seen in
the stone pine of Italy, is very frequent among the Mimosas. The deep
blue of the tropic sky seen through their finely divided foliage has an
extremely picturesque effect.
The Heath form[19] belongs more especially to the old world, and
particularly to the African continent and islands: taking for our
guides physiognomic character and general aspect, we may class under
it the Epacrideæ and Diosmeæ, many Proteaceæ, and those Australian
Acacias which have mere leaf-stalks instead of leaves (phyllodias).
This form has some points of similarity with that of needle trees, and
the partial resemblance enhances the effect of the pleasing contrast
which, when these two are placed together, is afforded by the abundant
bell-shaped blossoms of the heaths. Arborescent heaths, like some other
African plants, extend to the northern shores of the Mediterranean:
they adorn Italy, and the cistus-covered grounds of the south of
Spain. The declivity of the Peak of Teneriffe is the locality where I
have seen them growing with the greatest luxuriance. In the countries
adjoining the Baltic, and farther to the north, the aspect of this form
of plants is unwelcome, as announcing sterility. Our heaths, Erica
(Calluna) vulgaris, Erica tetralix, E. carnea, and E. cinerea, are
social plants, and for centuries agricultural nations have combated
their advance with little success. It is remarkable that the extensive
genus which is the leading representative of this form appears to be
almost limited to one side of our planet. Of the 300 known species of
Erica only one has been discovered across the whole extent of the New
Continent, from Pensylvania and Labrador to Nootka and Alashka.
The Cactus form,[20], on the other hand, is almost exclusively
American. Sometimes spherical, sometimes articulated or jointed,
and sometimes assuming the shape of tall upright polygonal columns
resembling the pipes of an organ, this group presents the most striking
contrast to those of Liliaceæ and Bananas. It comprises some of the
plants to which Bernardin de St. Pierre has applied the term of
“vegetable fountains in the desert.” In the waterless plains of South
America the animals suffering from thirst seek the melon-cactus, a
spherical plant half buried in the dry sand, and encased in formidable
prickles, but of which the interior abounds in refreshing juice. The
stems of the columnar cactus rise to a height of 30 or 32 feet; they
are often covered with lichens, and, dividing into candelabra-like
branches, resemble, in physiognomy, some of the Euphorbias of Africa.
While the above-mentioned plants flourish in deserts almost devoid of
other vegetation, the Orchideæ[21] enliven the clefts of the wildest
rocks, and the trunks of tropical trees blackened by excess of heat.
This form (to which the Vanilla belongs) is distinguished by its bright
green succulent leaves, and by its flowers of many colours and strange
and curious shape, sometimes resembling that of winged insects, and
sometimes that of the birds which are attracted by the perfume of the
honey vessels. Such is their number and variety that, to mention only
a limited district, the entire life of a painter would be too short
for the delineation of all the magnificent Orchideæ which adorn the
recesses of the deep valleys of the Andes of Peru.
The Casuarina form[22], leafless, like almost all species of Cactus,
consists of trees with branches resembling the stalks of our
Equisetums. It is found only in the islands of the Pacific and in
India, but traces of the same singular rather than beautiful type are
seen in other parts of the world. Plumier’s Equisetum altissimum,
Forskäl’s Ephedra aphylla from the north of Africa, the Peruvian
Colletias, and the Siberian Calligonum pallasia, are nearly allied to
the Casuarina form.
As the Banana form shews the greatest expansion, so the greatest
contraction of the leaf-vessels is shewn in Casuarinas, and in the form
of Needle trees[23] (Coniferæ). Pines, Thuias, and Cypresses, belong
to this form, which prevails in northern regions, and is comparatively
rare within the tropics: in Dammara and Salisburia the leaves, though
they may still be termed needle-shaped, are broader. In the colder
latitudes the never-failing verdure of this form of trees cheers the
desolate winter landscape, and tells to the inhabitants of those
regions that when snow and ice cover the ground the inward life of
plants, like the Promethean fire, is never extinct upon our planet.
Like mosses and lichens in our latitudes, and like orchideæ in the
tropical zone, plants of the Pothos form[24] clothe parasitically the
trunks of aged and decaying forest trees: succulent herbaceous stalks
support large leaves, sometimes sagittate, sometimes either digitate
or elongate, but always with thick veins. The flowers of the Aroideæ
are cased in hooded spathes or sheaths, and in some of them when they
expand a sensible increase of vital heat is perceived. Stemless, they
put forth aerial roots. Pothos, Dracontium, Caladium, and Arum, all
belong to this form, which prevails chiefly in the tropical world. On
the Spanish and Italian shores of the Mediterranean, Arums combine
with the succulent Tussilago, the Acanthus, and Thistles which are
almost arborescent, to indicate the increasing luxuriance of southern
vegetation.
Next to the last-mentioned form of which the Pothos and Arum are
representatives, I place a form with which, in the hottest parts of
South America, it is frequently associated,--that of the tropical
twining rope-plants, or Lianes,[25] which display in those regions, in
Paullinias, Banisterias, Bignonias, and Passifloras, the utmost vigour
of vegetation. It is represented to us in the temperate latitudes by
our twining hops, and by our grape vines. On the banks of the Orinoco
the leafless branches of the Bauhinias are often between 40 and 50 feet
long: sometimes they hang down perpendicularly from the high top of the
Swietenia, and sometimes they are stretched obliquely like the cordage
of a ship: the tiger-cats climb up and descend by them with wonderful
agility.
In strong contrast with the extreme flexibility and fresh
light-coloured verdure of the climbing plants, of which we have
just been speaking, are the rigid self-supporting growth and bluish
hue of the form of Aloes,[26] which, instead of pliant stems and
branches of enormous length, are either without stems altogether, or
have branchless stems. The leaves, which are succulent, thick, and
fleshy, and terminate in long points, radiate from a centre and form
a closely crowded tuft. The tall-stemmed aloes are not found in close
clusters or thickets like other social or gregarious plants or trees;
they stand singly in arid plains, and impart thereby to the tropical
regions in which they are found a peculiar, melancholy, and I would
almost venture to call it, African character. Taking for our guides
resemblance in physiognomy, and influence on the impression produced by
the landscape, we place together under the head of the Aloe form, (from
among the Bromeliaceæ) the Pitcairnias, which in the chain of the Andes
grow out of clefts in the rocks; the great Pournetia pyramidata, (the
Atschupalla of the elevated plains of New Granada); the American Aloe,
(Agave); Bromelia aranas and B. karatas; from among the Euphorbiaceæ
the rare species which have thick short candelabra-like divided
stems; from the family of Asphodeleæ the African Aloe and the Dragon
tree, (Dracæna draco); and lastly, from among the Liliaceæ, the tall
flowering Yucca.
If the Aloe form is characterised by an almost mournful repose and
immobility, the form of Gramineæ,[27] especially the physiognomy
of arborescent grasses, is characterised, on the contrary, by an
expression of cheerfulness and of airy grace and tremulous lightness,
combined with lofty stature. Both in the East and West Indies groves of
Bamboo form shaded over-arching walks or avenues. The smooth polished
and often lightly-waving and bending stems of these tropical grasses
are taller than our alders and oaks. The form of Gramineæ begins
even in Italy, in the Arundo donax, to rise from the ground, and to
determine by height as well as mass the natural character and aspect of
the country.
The form of Ferns,[28] as well as that of Grasses, becomes ennobled
in the hotter parts of the globe. Arborescent ferns, when they reach
a height of above 40 feet, have something of a palm-like appearance;
but their stems are less slender, shorter, and more rough and scaly
than those of palms. Their foliage is more delicate, of a thinner and
more translucent texture, and the minutely indented margins of the
fronds are finely and sharply cut. Tree ferns belong almost entirely
to the tropical zone, but in that zone they seek by preference the
more tempered heat of a moderate elevation above the level of the sea,
and mountains two or three thousand feet high may be regarded as their
principal seat. In South America the arborescent ferns are usually
found associated will the tree which has conferred such benefits on
mankind by its fever-healing bark. Both indicate by their presence the
happy region where reigns a soft perpetual spring.
I will next name the form of Liliaceeous plants,[29] (Amaryllis,
Ixia, Gladiolus, Pancratium) with their flag-like leaves and superb
blossoms, of which Southern Africa is the principal country; also the
Willow form[30], which is indigenous in all parts of the globe, and
is represented in the elevated plains of Quito, (not in the shape
of the leaves but in that of the ramification), by Schinus Molle;
Myrtaceæ[31], (Metrosideros, Eucalyptus, Escallonia myrtilloides);
Melastomaceæ[32], and the Laurel form[33].
It would be an enterprise worthy of a great artist to study the aspect
and character of all these vegetable groups, not merely in hot-houses
or in the descriptions of botanists, but in their native grandeur in
the tropical zone. How interesting and instructive to the landscape
painter[34] would be a work which should present to the eye, first
separately and then in combination and contrast, the leading forms
which have been here enumerated! How picturesque is the aspect of
tree-ferns spreading their delicate fronds above the laurel-oaks of
Mexico; or groups of plantains over-shadowed by arborescent grasses
(Guaduas and Bamboos)! It is the artist’s privilege, having studied
these groups, to analyse them: and thus in his hands the grand and
beautiful form of nature which he would pourtray resolves itself, (if
I may venture on the expression) like the written works of men, into a
few simple elements.
It is under the burning rays of a tropical sun that vegetation displays
its most majestic forms. In the cold north the bark of trees is covered
with lichens and mosses, whilst between the tropics the Cymbidium and
fragrant Vanilla enliven the trunks of the Anacardias, and of the
gigantic fig trees. The fresh verdure of the Pothos leaves, and of the
Dracontias, contrasts with the many-coloured flowers of the Orchideæ.
Climbing Bauhinias, Passifloras, and yellow flowering Banisterias,
twine round the trunks of the forest trees. Delicate blossoms spring
from the roots of the Theobroma, and from the thick and rough bark of
the Crescentias and the Gustavia.[35] In the midst of this profusion of
flowers and fruits, and in the luxuriant intertwinings of the climbing
plants, the naturalist often finds it difficult to discover to which
stem the different leaves and flowers really belong. A single tree
adorned with Paullinias, Bignonias, and Dendrobium, forms a group of
plants which, if disentangled and separated from each other, would
cover a considerable space of ground.
In the tropics vegetation is generally of a fresher verdure, more
luxuriant and succulent, and adorned with larger and more shining
leaves than in our northern climates. The “social” plants, which often
impart so uniform and monotonous a character to European countries,
are almost entirely absent in the Equatorial regions. Trees almost as
lofty as our oaks are adorned with flowers as large and as beautiful
as our lilies. On the shady banks of the Rio Magdalena in South
America, there grows a climbing Aristolochia bearing flowers four
feet in circumference, which the Indian boys draw over their heads
in sport, and wear as hats or helmets.[36] In the islands of the
Indian Archipelago the flower of the Rafflesia is nearly three feet in
diameter, and weighs above fourteen pounds.
The great elevation attained in several tropical countries not only
by single mountains but even by extensive districts, enables the
inhabitants of the torrid zone--surrounded by palms, bananas, and the
other beautiful forms proper to those latitudes--to behold also those
vegetable forms which, demanding a cooler temperature, would seem to
belong to other zones. Elevation above the level of the sea gives
this cooler temperature even in the hottest parts of the earth; and
Cypresses, Pines, Oaks, Berberries and Alders, (nearly allied to our
own) cover the mountainous districts and elevated plains of Southern
Mexico and the chain of the Andes at the Equator. Thus it is given to
man in those regions to behold without quitting his native land all
the forms of vegetation dispersed over the globe, and all the shining
worlds which stud the heavenly vault from pole to pole.[37]
These and many other of the enjoyments which Nature affords are wanting
to the nations of the North. Many constellations, and many vegetable
forms,--and of the latter, those which are most beautiful, (palms, tree
ferns, plantains, arborescent grasses, and the finely-divided feathery
foliage of the Mimosas),--remain for ever unknown to them. Individual
plants languishing in our hot-houses can give but a very faint idea of
the majestic vegetation of the tropical zone. But the high cultivation
of our languages, the glowing fancy of the poet, and the imitative art
of the painter, open to us sources whence flow abundant compensations,
and from whence our imagination can derive the living image of that
more vigorous nature which other climes display. In the frigid North,
in the midst of the barren heath, the solitary student can appropriate
mentally all that has been discovered in the most distant regions, and
can create within himself a world free and imperishable as the spirit
by which it is conceived.