Chapter II: Front Matter (2)

The double seed-leaf plants include all the highest and most specialized varieties. Bark, stem, pith, and concentric rings of growth are clearly defined; the leaves are netted-veined, and the petals grouped in fours or fives or multiples of these numbers. The lowest class, represented by the catkin-bearers, as the birch and alder, the poplar and the oak, and by plants allied to the nettle and to the laurel, are nearly related to the highest gymnosperms. Next in order are the crown-bearers, or flowers with corollas, as the rose family, which includes most of our fruit yielders, from strawberries to apples; while the highest and most perfect of all are plants in which the petals are united together in bell-shape or funnel fashion. Such are the convolvulus and honeysuckle, the olive and ash, and at the top of the plant-scale, the family of which the daisy is the most familiar representative. Its position among plants corresponds to man’s position among animals. As he, in virtue of being the most complex and highly specialized, is at their head, albeit many exceed him in bulk and strength, so is the daisy with its allies, for like reasons, above the giants of the forest.

The primary function for which the organs of plants known as flowers exists is not that which man has long assumed. He once thought that the earth was the centre of the universe until astronomy dispelled the illusion, and there yet lingers in him an old _Adam_ of conceit that everything on the earth has for its sole end and aim his advantage and service. Evolution will dispel that illusion. But our delight in the colors and perfumes of flowers will not be lessened, while wonder will have larger field for play in learning that the colored leaves known as flowers, together with their scent and honey, have been developed in furtherance of nature’s supreme aim--the preservation and increase of the species. And truly the contrivances to secure this which are manifest in plant-life are astounding even to those who perceive most clearly the unity of function which connects the highest and lowest life-forms together. It is difficult, nay, wellnigh impossible, to deny the existence of a rudimentary consciousness in the efforts of certain plants to secure fertilization. Take, for example, the well-known aquatic plant, _Vallisneria spiralis_. When the male flowers detach themselves and float about the water, the female flowers develop long spiral stalks by which to reach them, and become fertilized by the discharge of pollen on their pistils. Most flowers have their male and female organs within the same petals, and in some cases fertilize themselves by scattering the pollen from the bursting stamens on the stigma or head of the pistil. But nature is opposed to this; “tells us in the most emphatic manner that she abhors perpetual self-fertilization,” with its resultant puny and feeble offspring; and we find a number of contrivances to prevent this, and to secure fertilization by the pollen of another plant, to the abiding gain all round of the plant, whose blood, as we may say, is thus mixed with that of a stranger. Two agencies--insects and the wind--undesignedly effect this; while in the dispersion of the matured seed, birds and other animals play an important, although equally unconscious, part.

Plants which are wind-fertilized have no gayly colored petals or sepals, and do not secrete water. Such are the naked-seeded groups whose sombre flowers are borne on dull brown cones; and, among cover-seeded groups, grasses and rushes, with their feathery flowers; and willows and birches, with their long waving clusters of catkins. All of these provide against the fitfulness of the wind, which is as likely to blow the pollen one way as another, by producing it in large quantities.

Plants which are insect-fertilized seek to attract their visitors by secreting honey and developing colored floral organs. The way in which this came about is probably as follows:

The common idea about flowers is that they are made up of petals and sepals, whereas the _essential_ parts are the stamens and pistils--_i. e._, the male, or pollen-producing organs, and the female, or seed-containing organs. The earliest flowers consisted of these alone, having no colored whorl of petals within another colored whorl of sepals, but were only scantily protected by leaves, as are many extant species. These the food-seeking insects then, as now, visited for the sake of the pollen, to the detriment of the plant, which lost the fertilizing stuff and gained nothing in return. To arrest this, certain plants began, especially when in the act of flowering, to secrete honey and store it in glands or nectaries, or near their seed-vessels, where the insects could not get at it without covering their bodies with some of the pollen, which they rubbed on the pistils of the plant next visited, and thus fertilized the ovule, provided that the plants were nearly related. Honey is sweeter to the taste than pollen, and the plants that produced the most honey stood the better chance of visits from insects, and therefore of fertilization, to the advantage of this species over others. As a rule, those which secrete honey have hairy coverings at the base of the petals, or other contrivances to prevent it being washed out by the rain or dew, or seized by useless insects, and we find curious interrelations established between plants and their desired visitors. Certain flowers adapt themselves to certain insects, and _vice versâ_, as where the plant has secreted the honey at the bottom of a long tube and the insect has developed a correspondingly long proboscis to gather it. By these and kindred devices the pollen is preserved for its sole function, the energy of the plant being conserved in the smaller quantity which it has to produce. As the honey was secreted as counter-attraction to the pollen, so the colored floral envelopes were developed to attract the insects, to the honey-secreting plant, and those floral whorls, both of petals and sepals, are modified or transformed stamens which have exchanged their function of pollen-producers for that of insect-allurers. And as both stamens and pistils are leaves aborted or modified for the special function of reproduction, Goethe’s well-known generalization that the leaf is the type of the plant has a large measure of truth in it.

But before speaking further about color-development in plants, it may be useful to say a little about color itself. Since everything is black in the dark, and moreover has no color in itself, it follows that color is in some way a property of light. Now light, which is itself invisible, is due to vibrations or oscillations set up in all directions by any luminous body--whether the sun or a rushlight--in the ethereal medium which pervades all space, and is composed of rays of different refrangibilities--_i. e._, change of direction in passing from one medium to another. White light is due to a combination of all these rays, ranging through innumerable gradations of color, from red to violet, and it is to the absence of one or more of them that the infinite variety of colors is due. If a body is quite opaque, or otherwise so constituted as to absorb none of the rays, it appears white; if it absorbs them all it appears black; if it absorbs green, blue, and violet, and not red, it appears red; if it absorbs red, orange, and violet and returns or reflects green, it appears green. The colors which bodies reflect are therefore regulated by their structure; the way in which their molecules are arranged determines the number and character of the light vibrations or ether waves which are returned to the eye and which rule the color we see--_e. g._, charcoal and the diamond are both pure carbon; the dull opacity of the one and the trembling splendor of the other are solely due to the arrangement of the several molecules of each.

It is thus obvious that any change in the nature or structure of a thing is accompanied by change in its color, and to this cause the various pigments in plants are to be referred.

All growth involves expenditure of the energy which the plant has stored within itself, and which becomes active when the hydrocarbons combine with oxygen, resulting in cellular change, and appearance of other colors than the green, which is due to chlorophyl. Thus may be explained the color of sprouting buds and young shoots and the more or less intensified colors of leaves and flowers--one and all due to oxidation, the minutest changes inducing subtle variations in color.

Whichever plants made the most show of color would the sooner catch the eye of insects, however dim their perception of the difference in colors might be, and would thus get fertilized before plants which made less display. Thus have insects been the main cause in the propagation of flowering plants; the plants in return developing the color-sense in insects. The flower nourishes the insect, the insect propagates the flower. Other contrivances to meet the need for fertilization might be cited, as the markings upon the petals to guide the insect to the nectary; the exhalation of scent by inconspicuous flowers, or by such as would attract visitors at night, and so forth; but enough has been adduced to show what is the chief, if not the sole, function discharged by flowers--the attraction of insects to aid in securing cross-fertilization. Nor does the provision stop here. The fertilized seed is not left to chance, but, like the fertilizing pollen, is intrusted to secondary agents, to the care of the birds and the breezes. Where not scattered by the bursting of the ovary it is winged with gossamer shafts, as in the dandelion, and carried by the wind, floated on gentlest zephyr or rushing storm to a genial soil. Such wind-wafted seeds, like wind-fertilized flowers, are rarely colored; neither are the seeds of the larger trees, since their abundance ensures notice by food-seeking animals; nor the nuts, which are protected by shelly coats. But other seeds inwrap themselves in sweet pulpy masses, called fruits, whose skins brighten as they ripen, and attract the eye of fruit-loving birds and beasts. The seeds pass through their stomachs undigested, and are scattered by them in their flight over wide areas. As with the brightest-hued and sweetest-scented flowers, so it is with the brightest and juiciest fruits; they sooner attract the visitor whose services they need, and thus gain advantage over less-favored members of their species, developing by the selective action of their devourers into the finest and pulpiest kinds.

PLANT GEOGRAPHY
--LOUIS FIGUIER

We can distinguish in Europe three great botanical regions. 1. The region of the North; 2. The Middle region; and 3. The region of the South, or Mediterranean.

The Northern region comprehends Lapland, Iceland, Sweden, Norway, and the northern provinces of Russia. The vegetation is monotonous; the ligneous species form only the one-hundredth part of the plants; the cryptogams predominate. The trees are principally coniferous and amentaceous. The oak, the hazel, and poplar are arrested at 60° N. lat.; the beech, the ash, and the lime at 63°; the conifers at 67°; barley and oats can be cultivated up to 70°. Spitzbergen, the most northerly island of Europe, situated between 76° 30′ and 81°, contains only ninety-three species of phanerogamous plants, belonging principally to the families of _Graminaceæ_, _Cruciferæ_, _Caryophyllaceæ_, _Saxifragaceæ_, _Ranunculaceæ_, and _Compositæ_. Among these plants there is scarcely a single tree or shrub, but only an under-shrub, _Empetrum nigrum_, and two small creeping willows.

Martius, to whom botanical geography is indebted for many valuable observations, made a voyage along the western coast of Norway, from Drontheim to North Cape, in recording which he has traced with a vigorous hand the picturesque vegetation of that country. “While disembarking I was much surprised to see cherry-trees bearing fruit about the size of peas. Lilac, mountain ash, black currant, and _Iris germanica_ were covered with expanding flowers. My astonishment ceased, however, when I learned that the spring had been a very fine one. The most common tree in the gardens and streets is the mountain ash. I remarked also four oaks (_Quercus Robur_), which appeared to suffer from the cold; in fact, upon the west coast of Norway the northern limit of the oak lies half a degree south of Drontheim. The ash is a more hardy tree, but it never attains the dimensions of the oak in Sweden, and in latitude 61° 18′ I noted the last of them. The lime lives at Drontheim, as do the poplar (_P. balsamifera_) and the horse chestnut; the lilac blooms in every garden. All fruit trees can only be cultivated as espaliers. Even in the most favored situations, the apple, pear, and plum do not ripen every year. In the environs of Drontheim, groups of elder, birch, fir, intermingled with ash, maple, aspen, bird-cherry, hazel, juniper, and willow crown the heights. The fields are dry and well exposed, while the meadows occupy the lower ground.

“Toward the north I pushed on to Cape Ladehamer, which is crowned with light-foliaged birches. In the fields and by the roadsides I found a great many plants which occupy similar situations in France. Nevertheless,” he continues further on, “the eye of the botanist was rejoiced by the sight of a vegetation belonging at once to the Flora of the Boreal regions of the Alps and of the seashore.” In the thickets grow _Geranium sylvaticum_, _Aquilegia vulgaris_, _Aconitum septentrionale_, _Pedicularis lapponica_, _Trientalis europæa_, _Paris quadrifolia_; in the less sheltered places, _Cornus suecica_, _Vaccinium Vitis-idæa_, _Polygonum viviparum_; in the marshes, the Bleaberry and _Geum rivale_; upon the sandy seashore, _Plantago maritima_, _Glaux maritima_, _Elymus arenarius_, _Triglochin maritimum_, and many others equally interesting to the botanist.

1. Willow; 2. Oak; 3. Sycamore; 4. Cedar; 5. Chestnut; 6. Olive]

“At Bodoë, in 67° 16′,” he continues, “I saw for the first time houses covered with turf, upon which grew many tufts of grass. According to my custom, I first examined the cultivated vegetables, but I saw only a few potatoes, peas, radishes, a few gooseberry-trees without fruit, and some fields of barley and rye. In the meadows just above the sea-level I found some plants which would have demonstrated to me, in the absence of other proofs, how much the climate of this country approaches that of the most elevated Alpine regions.

“At Hammerfest, which is under 70° 48′ north latitude, all attempts at cultivation had disappeared. The energies of the place are turned to commerce; it is from curiosity rather than for profit or utility that a few vegetables are cultivated.

“Near the city I observed rich meadows, that were cut once a year, and some herds of half-wild reindeer, which grazed and roamed about freely. We shall deceive ourselves, however, if we consider Hammerfest a dull or melancholy city. Its principal streets, on the contrary, consist of very fair new wooden houses, well ordered, and in all respects comfortable. These are the habitations of the better class of inhabitants. The houses of the lower classes are poorer and older; borrowing, however, a particular charm from the flowery turf with which they are covered. The roofs are formed of great squares of turf, on which a number of plants have germinated and grow vigorously. In seeing these aerial gardens I have for the first time been able to comprehend the phrase ‘_in tectis_’, which often occurs in the writings of Linnæus, indicative of the locality. In short, it was upon the roofs of houses that the learned botanist of Upsala herborized at Hammerfest; indeed, I frequently borrowed a ladder myself from the proprietor in order to gather the plants which grew round the chimney of one of these picturesque old houses. What I often found there were _Cochlearia anglica_, _Lychnis diurna_, _Chrysanthemum inodorum_, Shepherd’s Purse, _Poa pratensis_, and _P. trivialis_. In autumn, when the flowers of _Chrysanthemum inodorum_ are in full bloom, these hanging meadows rival in beauty those of our own more genial climate, and give the city a smiling physiognomy which contrasts most happily with the severe aspect of surrounding Nature. _Ranunculus glacialis_, _Arabis alpina_, _Silene acaulis_, _Saxifraga nivalis_, Bilberries, _Diapensia lapponica_, _Salix reticulata_, _S. herbarcea_, etc., grow in the neighborhood.

“How great was my surprise on landing at the North Cape, in latitude 71°, to find myself in the middle of the richest subalpine meadows that can be imagined! high and tufted grass, which reached my knees. I found here, in short, at the northern extremity of Europe, the flowers which had so often attracted my admiration at the foot of the Swiss Alps; there they were, as vigorous, as brilliant, and much larger than among the mountains.”

The mid-European region includes southern Russia, Germany, Holland, Belgium, Switzerland, the Tyrol, and the British Isles, Upper Italy, and the greater part of France. This region, whose exact limits it would be difficult to trace, is very different from the preceding. It is milder, more temperate; its woods and forests consist essentially of oak (_Quercus Robur_), to which we may add chestnut, beech, birch, elm, hornbeam, alder, etc.; but the oak predominates. These trees, all of which lose their leaves during winter, give to the landscape a very peculiar feature, varying with the season. This region is especially favorable to the cultivation of the cereals. An oblique line, drawn from east to west, with certain inflections of its course, but ranging between the forty-seventh and forty-eighth parallel, and inclining a little toward the north, would divide it into two zones--one, the Northern, in which the vine and the mulberry yield to the rigor of winter, whose forests are chiefly composed of conifers, where the culture of the apple and pear takes their place, and which includes more _Cyperacæ_, _Rosaceæ_, and _Cruciferæ_; the other, the Southern, characterized by the culture of the vine, the mulberry, and the maize, and in which _Labiatæ_ begin to predominate.

In the Southern region, the Mediterranean forms the centre. It is a vast basin, whose shores present a vegetation which, if not identical, is at least analogous in its whole extent. _Labiatæ_ abound there, and in certain seasons the air is filled with their sweet perfume. To this extensive family we may add a large number of _Caryophyllaceæ_, _Cistaceæ_, _Liliacæ_, and _Boraginaceæ_. The Mediterranean draws its distinctive character, however, from the vast extent of uncultivated country, where the kermes oak, _Phillyrea_, the evergreen oak, and various half frutescent Labiatæ, reign supreme. These plants more especially abound in Italy, Spain, Greece, Algeria, and in the northern portion of Asia Minor. Nevertheless, a new vegetation makes its appearance at Rhodes and Jaffa, which becomes closely connected with that of Egypt. The vegetation of the Mediterranean often presents itself with a smiling and agreeable aspect. Clumps of odorous myrtles, _Arbutus_, and _Vitex Agnus-castus_, frequently occur on its shores; magnificent oleanders, whose praises have been sung by the poets, occupy the edges of the brooks. In Italy, Sicily, and Spain, the orange-trees bear without cessation flowers and fruit. The prickly pear (_Opuntia vulgaris_), and the American _Agave_, naturalized here, form impenetrable hedges in the southern parts of these countries, to which they give a marked and very characteristic landscape. The forests consist essentially of the evergreen oak (_Quercus Ilex_), whose persistent leaves remain until after their third year, and whose acorns, which have a very agreeable taste, form a considerable portion of the people’s food, and of the cork-tree (_Quercus Suber_), mixed with other characteristic trees and shrubs, such as _Erica arborea_, numerous species of _Cistus_, with ephemeral flowers, often large and of dazzling brilliance, and of _Cytisus_, _Genista_, etc.

Among the other species characteristic of these happy regions we may cite the cypress (_Cupressus_), the Aleppo pine, the stone pine, planes, the olive, which we scarcely meet with elsewhere; mastic-tree (_Pistacia lentiscus_), and the pomegranate (_Ceratona Siliqua_), etc.

Over a great part of the south coast of Sicily, a palm, the _Chamærops humilis_, with fan-like foliage, waves sometimes beside the date, from the bosom of a clump of oranges and citrons, its tall stipe crowned with an elegant panicle of drooping and feather-like leaves.

It would require a volume to give even an idea of the rich and varied vegetation of Asia. We must limit ourselves to a rapid glance of the features most characteristic of its Northern, Central, and Southern divisions.

The Northern region, or Siberia, forms a botanical region in close connection with the northern region of Europe in the one direction, and with its own middle region in the other. It has its own peculiar character, nevertheless, from the predominance of certain families, such as _Leguminosæ_, _Ranunculaceæ_, _Cruciferæ_, _Liliaceæ_, and _Umbelliferæ_. Some genera are remarkable for the number of their species; we may quote _Astragalus_ among the _Leguminosæ_; _Spiræa_ among the _Rosaceæ_; and _Artemisia_ among the _Compositæ_. Considering that the mean temperature varies from 29° to 46° Fahr., we can not reckon on a condition of vegetation very varied. Forests are formed by larch, spruce, _Pinus Cembra_, _P. sibirica_, _P. sylvestris_, etc.; white and balsam poplars and isolated balsamic plants, dwarf birches, service-trees, alder buckthorn, alders, willows, accompany them, while whortleberries and rhododendrons form the under-shrubs. The flora of the steppes of Kamtchatka does not differ materially from that of the pasturages of central Europe. According as the spectator expects these to be rich or sterile, he is the more or less surprised to find stately tulips and graceful irises mingling with the grassy turf in spring, but the wormwood (_Artemisia_) and other monotonous forms of vegetation succeed them.

Humboldt assigns to the forests of the Ural the vegetation characteristic of a park. “They present,” he says, “an alternation consisting of a mixture of needle-leaved and round-leaved trees, and lawns; an assemblage which is completed by masses of brushwood, formed by wild roses, honeysuckles, and junipers, while _Hesperis_, _Polemonium_, _Cortusa_, _Mathioli_, magnificent primroses, and larkspurs form a perfect carpet of flowers; while the water buckbean, with white blossoms, is the grace of the marshes.” He saw also “on the banks of the Irtisch great spaces entirely colored red by _Epilobium_, with which were associated tall-stemmed larkspurs (_Delphinium_), with blue flowers, and the fiery-scarlet _Lychnis chalcedonica_.”

The Central region consists of northern China and Japan. The magnolias--those grand-leaved trees, with magnificent flowers and delicate aroma, which give such an attractive feature to gardens where they can be cultivated--are natives of this vast region. So is the camellia, which has been, as it were, naturalized in the greenhouses of Europe, whose evergreen, glossy, and persistent foliage is the admiration of travelers, and of which we may reckon upward of 700 varieties; and the tea-plant (_Camellia Thea_), of whose leaves so many millions of pounds are annually imported into Europe. Also the _Aucuba_, with coriaceous leaves and clustered flowers, so ornamental in our gardens and shrubberies; _Celastrus_, hollies, spindle-tree, _Lagerströmia_, _Spiræa_, _Elæagnus_, etc.

The most remarkable trees and shrubs besides these are the palm, _Raphis flabelliformis_; the paper mulberry (_Broussonetia papyrifera_); _Osmanthus_, whose flowers are employed to give flavor to tea leaves; the ebony-tree (_Diospyros Kaki_), with white flowers, and berries of a cherry-red, and of a delicious flavor; the loquat (_Eriobotrya japonica_); _Salisburia adiantifolia_, which is planted round the temples; yews (_Taxus nucifera_ and _verticillata_); cypress (_Cupressus japonica_); junipers, thujas, oaks (_Quercus glabra_ and _glauca_); _Alnus japonica_, _Juglans nigra_, and several species of laurels and maples.

Among the cultivated plants we find rice, wheat, barley, oats, _Sorghum vulgare_, Sago (_Cycas revoluta_), taro (_Caladium esculentum_), _Convolvulus Batatas_, apple, pear, quince, plum, apricot, peach, orange, radish, cucumber, gourds, watermelons, anise (_Pimpinella Anisum_), peas, beans, hemp, and cotton (_Gossypium herbaceum_)--a remarkable mingling of vegetable productions, which transports us at one moment from Asia to Europe, and at the next from America to Asia. We might dwell upon a crowd of ornamental plants, many of which are now well known in Europe, as the _Glycine_, the lily of Japan, tiger lily, and Chinese primrose.

The Southern region of Asia comprehends the two Indian peninsulas. Here non-tropical species disappear, or only present themselves very rarely. Tropical families become more numerous; the trees cease to lose their leaves; ligneous species are more numerous than without the tropics; the flowers are larger, more magnificent; climbing, creeping, and parasitic plants increase in number and size. India may be considered the true country of aromatic plants. Nor is the rich soil less fruitful in the production of suitable timber for constructive purposes.

Among the most abundant arborescent plants in this botanical region are _Bombax_, _Sapindus_, _Mimosa_, _Acacia_, _Cassia_, _Jambosa_, _Gardenia_; ebony (_Diospyros Ebenus_) has been celebrated for its black-colored solid wood from the most ancient times; _Bignonia_; teak (_Tectona grandis_), is a magnificent tree, which furnishes timber well adapted for building purposes from its great endurance; _Isonandra Gutta_ produces _gutta-percha_; laurels have an aromatic bark; the nutmeg-tree (_Myristica_) produces seeds which are employed as spice; figs (_Ficus religiosa_, _indica_, _elastica_); palms, such as the Borassus (_Borasus flabelliformis_) with magnificent large fan-like leaves; _Sagus_, whose soft pulp yields sago, a farinaceous product very rich in starch; _Calamus_, whose twining and creeping stem is sometimes upward of 500 feet in length, of one uniform thickness, and of which the canes used in Europe are made; areca (_Areca Catechu_), the nut of which is a favorite masticatory with the natives; _Corypha umbraculifera_, the trunk of which, sometimes reaching the height of sixty or seventy feet, is crowned with an ample tuft of leaves spread out in umbrella form, covering a space of eighteen feet; _Dracæna_; screw-pines (_Pandanus_); last, but not least, the bamboo.

If we throw a glance, moreover, at the plants under cultivation, we find them equally important: rice, earth-nut, _Sorghum_, Indian corn, the cocoanut, the elegant and useful tree which gives to man almost all the necessaries of life, supplying him at once with shelter, food, light, heat, and clothing; the clove-tree (_Caryophyllus aromaticus_), the unopened flower of which is the well-known clove; pepper (_Piper nigrum_), the fruit of which, gathered before maturity, has been constantly brought to Europe since the expedition of Alexander the Great; and the betel (_Chavica Betel_), with bitter and aromatic leaves, in which the southern Asiatics inclose a few slices of the areca-nut, which they chew; the tamarind (_Tamarindus indica_), a magnificent tree, the fruit of which incloses a pulp of acid flavor; the mango (_Mangifera indica_), whose much-vaunted fruit has a sweet and richly perfumed flavor accompanied with a grateful acidity; the mangosteen (_Garcinia Mangostana_), whose berry incloses, under a bitter and astringent epicarp, a delicious pulp; the banana, whose yellow-clustered fruit, each six or eight inches long, furnishes a very nourishing food; the rose apple (_Jambosa vulgaris_), the guava (_Psidium pomiferum_), with yellow fruit of the size of a pear; oranges, watermelons, sugar-cane, and coffee.

Africa, like Asia, presents three very distinct regions: 1st, the Northern, which comprehends the Mediterranean littoral and the Sahara; 2d, the Central, which is tropical; 3d, the Southern, which includes the Cape of Good Hope.

The Mediterranean region, by which we mean the African littoral bathed by the Mediterranean, includes Algeria from the northern slopes of the Atlas to the sea, and the Delta of the Nile. This part of Africa represents, in many respects, a vegetation analogous to that of South Europe. In the mountain region of North Africa all the plants of Central Europe may be cultivated with advantage. The vine prospers in the neighborhood of Tlemcen, Milianah, Mascara, and Medeah, where the colonists and even the natives have undertaken its cultivation. The olive, so generally spread over North Africa, constitutes one of the chief sources of wealth to the Kabyle tribes. The cork-tree forms immense forests in the lower mountain region of the littoral: in the province of Constantine, gathering the cork has become an important trade since its conquest by France. With respect to the Sahara, M. Cosson, a traveler and botanist, thus expresses himself:

“Northern Africa is especially characterized by the extreme rarity of rains, the dryness of the atmosphere, and the extremes of temperature; the absence of great ranges of mountains and of permanent water-courses gives an aspect quite special to the desert-like vegetation. The number of species growing spontaneously does not exceed 500. The greater number of these are perennials, which grow in tufts, and have a dry and sterile aspect, giving them a characteristically rugged and hard appearance. The families represented in the Algerian Sahara in greatest number are _Compositæ_, _Graminaceæ_, _Leguminosæ_, _Cruciferæ_, and _Chenopodiaceæ_. Among the ligneous species are Tamarisks, a genus of elegant flowering shrubs, and the _Pistacia atlantica_. The date-tree is, however, the chief source of wealth in the gardens of the oases. This tree is cultivated, not alone for the abundance and variety of its products, but also for its shade, which secures other cultivated plants from the violence of the winds, and maintains in the soil the moisture required for the cultivation of other crops.

“Besides the date, an oasis generally presents an abundant crop of figs, pomegranates, apricots, frequently the vine. The peach, the quince, the pear, and the apple, are planted in gardens, and in the oases, the citron, the orange-tree, olives, barley, more rarely still, wheat, are cultivated in the irrigated lands of the neighborhood, and in the intervals between the date plantations. Onions, beans, carrots, turnips, and cabbages, occupy a large place among the plants cultivated. Pimento is also largely cultivated for the stimulating properties of its fruit, which render it a favorite condiment with the Arabs. The egg-plant and the tomato are cultivated in some gardens for their fruit. Numberless species of _Cucurbitaceæ_ are also sown in the gardens in summer, and sometimes attain a great size. The gombo (_Hibiscus esculentus_) is cultivated here and there by the negroes for its mucilaginous fruit. The industrial and fodder plants are principally hemp, represented by a dwarf variety (Haschich), which is not employed as a textile plant, but its extremities are smoked by some of the less fervent Mussulmans. Tobacco is also cultivated. Henna (_Lawsonia inermis_), the leaves of which have been employed in dyeing a black color, scarcely exists except in the oasis of Ziban.”

The Central region is only very imperfectly known, in consequence of the terribly insalubrious nature of its coast. The same forms of vegetation, however, prevail there which are found in other tropical regions. We may remark here that the plants, which are usually herbaceous in countries without the tropics, become ligneous in these regions. This is the case with plants of the families _Rubiaceæ_ and _Malvaceæ_. We note here also the almost entire disappearance of _Cruciferæ_ and _Caryophyllaceæ_. The prevailing families are _Leguminosæ_, _Terebinthaceæ_, _Malvaceæ_, _Rubiaceæ_, _Acanthaceæ_, _Capparidaceæ_, and _Anonaceæ_. If we take a glance at prevailing vegetation proper to this region of Africa, we find upon the humid coasts impenetrable forests formed of mangroves (_Rhizophora Mangle_), and _Avicennia tomentosa_, _Musa_, _Canna_, _Amomum_, _Pandanaceæ_, gigantic _Malvaceæ_ (such as the baobab), _Bromeliaceæ_, _Aroideæ_. Aloes (_Aloe socotrina_) furnishes the aloes of medicine; and several fleshy Euphorbias impress their strange characteristics upon the vigorous vegetation of this region.

It would be depriving African vegetation of its richest ornament not to mention its admirable palms. At their head stands the oil palm (_Elæis guineensis_), the fruit of which, of the size of an olive, contains so much oil that the liquid flows out when it is pressed between the fingers. The seed contains a sort of butter. The sap of this precious tree yields an excellent wine; its leaves prove excellent food for sheep and goats. But the true palm wine is produced from _Raphia vinifera_. Another remarkable member of this elegant family is _Lodoicea Seychellarum_, the fruit of which is larger than a man’s head and weighs upward of twenty pounds; it sometimes floats as far as the coast of India. It is a fact worthy of remark that in this region very few ferns or orchids are observed, and yet these groups of plants are extremely numerous in other tropical countries.

Among the exotic vegetables which are successfully cultivated in central Africa we may reckon maize, rice, _Sorghum_, Indian corn, manioc, _Caladium esculentum_, belonging to the family of the _Araceæ_, the rhizome and leaves of which are alimentary; the banana, the mango, the papaw-tree (_Carica Papaya_), the fruit of which, about the size of a small melon, is eaten either raw or cooked, and the pulp mixed with sugar forms a delicious marmalade; the pineapple, figs, coffee, sugar-cane, ginger, various species of _Dolichos_, the earth-nut, cotton, tobacco, and the tamarind.

The Southern region of the Cape of Good Hope is the country of the species of _Protea_, _Pelargonium_, _Epacridaceæ_, _Oxalis_, and _Ixia_, which decorate our hothouses and parterres. No other country can compare with this region for the prodigious abundance and dimensions of its heaths. While the plains of Europe, the Alps included, scarcely yield a dozen species, at the Cape there are many hundreds. They attain sometimes the height of fifteen or sixteen feet. Their leaves are small, inconspicuous, and acicular; but their flowers are large, and the colors which decorate them brilliant in the extreme, varying from the softest shades to dazzling ones.

The flora of this region is rich in vegetable forms, but it is by no means smiling in its aspect. We find no true forests, grand and sombre, in the whole region; there are few creeping plants, but, on the other hand, there are many succulents. The most characteristic families are the _Restiaceæ_, _Iridaceæ_, _Proteaceæ_, _Ericaceæ_, _Mesembryanthaceæ_, _Rutaceæ_, _Gernaiaceæ_, _Oxalidaceæ_, and _Polygalaceæ_. Among the characteristic genera we may mention the _Ixia_; _Gladiolus_, with their sword-shaped leaves and party-colored flowers; _Strelitzia_, so remarkable for their inflorescence, and for their blue and yellow flowers; _Protea_, so named for their diversity of appearance; _Leucadendron_, of which one species, _L. argenteum_ (the silver-tree), rises to the height of from thirty to forty feet, its branches bearing lanceolate leaves, silky and silvery; _Helichrysum_ and _Gnaphalium_, corymbiferous composites, better known as _Immortelles_; _Mesembryanthemum_, or ice-plants; _Stapelia_, leafless asclepiads, with angular fleshy stem and showy flowers, but somewhat fœtid odor; _Phylica_, a genus of Rhamnads somewhat resembling heaths, with abundant evergreen foliage and small cottony heads of white flowers; _Pelargonium_, of which an infinite variety of forms, the result of culture, are known; _Oxalis_, the evergreen _Sparmannia_, whose white flowers, stamens with purple filaments and irritable anthers, are so ornamental in orangeries. It is upon the sandy coast of this curious botanical region that the species of _Stapelia_, _Iridaceæ_, _Mesembryanthemum_, and _Diosma_ abound. The heaths and crassulas grow upon the slopes of the mountains.

The cultivated plants are the cereals, most of the fruits and vegetables of Europe, the sorghum of Kaffirland, yam, banana, tamarind, and guava.

Vegetation is richer and more varied in America than in any other part of the globe. Beginning with North America, we find its polar vegetation quite analogous to that of Europe and Asia under the same latitudes. The willow, birch, and poplar, exposed to the persistent action of the cold, become stunted bushes; and saxifrages, mosses, and lichens prevail.

Without dwelling on the Arctic regions, then, we may divide this immense country into two regions; one of which, descending as far as 36°, may be called the Northern region; the other, comprehended between 36° and 30° of latitude, will constitute the Southern region.

The Northern region well deserves to be called the region of _Aster_ and _Solidago_; those beautiful composites abound there with _Liatris_, _Rudbeckia_, and _Galardia_, of the same family. _Œnothera_, _Clarkia_, _Andromeda_, and _Kalmia_, charming ornamental plants, well known in our flower gardens, likewise characterize this vegetable zone. Among the most abundant arborescent species, we may mention numerous species of pine, fir, larch, _Thuja_, juniper; no less than twenty-seven species of willow; twenty-five of oak, beeches, chestnuts, elms, hornbeams, alders, birches, poplars, and ashes. With these are mingled the American plane, _Liquidambar_, the trunk and branches of which furnish juices used in medicine; the tulip-tree, with singularly truncate leaves and large, spreading, solitary, yellowish flowers; different species of maple, lime, _Robinia_, and walnut. Together with these numerous and varied arborescent species, which attain considerable dimensions, grow the _Myrica cerifera_, which furnishes an abundant wax drawn from the fruit by boiling; the currant (_Ribes_), with colored and ornamental flowers in great varieties of red, yellow, and white; the elegant _Andromeda_, _Azalea_, _Rhododendron_, and _Spiræa_, present themselves in endless varieties; sumacs, a species of which (_Rhus toxicodendron_), with greenish yellow flowers, contains a juice so acrid that contact with it produces blisters and erysipelas, and is a dangerous poison; _Ceanothus_, hollies, and buckthorns.

In the Southern region the vegetation somewhat resembles that of the tropics, being a transition between that of the temperate and torrid zones. Walnuts, elms, chestnuts, and oaks are found there, and with them three species of palms, one of which is _Chamærops Palmetto_; species of _Yucca_; of _Zamia_, among the _Cycadaceæ_; _Passiflora_; of woody twining plants, such as _Bignonia sapindus_; cacti, and laurels. Lastly, by the side of tulip-trees, _Pavia_, and _Robinia_, grow magnificent species of _Magnolia_, of which this is the true domain. The vegetation of this region is thus remarkable in its variety. The sugar-cane, indigo, cotton, and tobacco cover the cultivated plains. In Missouri, Texas, Arkansas, and Mexico, the great colony of the cacti raise their lofty stems. In this region _Cactus_, _Opuntia_, _Cereus_, _Echinocactus_, and _Melocactus_, raise their oddly branching stems and clustering flowers, the most remarkable of all doubtless being _Cereus giganteus_. It inhabits the wildest and most inaccessible regions, requiring little or no soil to attain a prodigious development. It has at first the appearance of an enormous tomahawk. Thence rises a column, three yards high, which branches off and assumes the shape of an immense candelabrum, the height of which may be twelve or thirteen yards. Mexico, according to the reports of botanists, may be divided into three regions of altitude. The first extends from the valleys as far as the oak forests--this is the region of palms, cotton, indigo, sugar-cane, coffee, and tropical fruits. The second, situated at an elevation of from 3,500 to 9,000 feet above the sea, is the temperate region. It stretches from the oak forests to the forests of _Coniferæ_. At this height the temperature is still sufficient to ripen some tropical fruits. The third, or cold region, occupies a space comprehended between the Conifers and perpetual snow. In many places it possesses a climate under which pear, apple, and cherry trees, and the potato, can still grow. In ascending from the foot of Orizaba, one sees successively appear and disappear _Mimosa_, _Acacia_, cotton, _Convolvulus_, _Bignonia_, oaks, palms, bananas, myrtles, laurels, _Terebinthaceæ_, tree-ferns, _Magnolia_, arborescent composites, plane, _Storax_, apples, pears, cherries, apricots, pomegranates, lemon and orange trees, orchids, _Fuchsia_, and _Cactus_.

The plains of Venezuela, known under the name of Llanos, are principally covered with grass-like plants, such as _Kyllingia_, _Cenchrus_, and _Raspalum_. With these we find a few dicotyledonous plants, such as _Turnera_; some _Malvaceæ_, and, what is very remarkable, species of _Mimosa_, with leaves quite sensitive to the touch, which the Spaniards call _Dornuderas_. The same race of cows which in Spain fatten upon sainfoin and clover, here find excellent nourishment in the herbaceous sensitive plants. The pasturage is richest, not only near rivers subject to inundations, but also where the trunks of the palm-trees are the most crowded, which can not be attributable to the shelter and protection which they have from the sun’s rays, since the palm of the Llanos (_Corypha tectorum_) has only a very few corrugated and palmate leaves, like those of _Chamærops_, and the lower are always parched and dried up. Besides the isolated trunks of palms we also find, here and there, in the Llanos, groups of palms, in which the _Corypha_ mingles with a tree of the family of _Proteaceæ_--a new species of _Rhopala_, with hard and resonant leaves. In the Llanos of Caracas, the _Corypha_ extends from the Mesa de Paja to Guayaval. More to the north and northwest it is replaced by another species of the same genus, with leaves equally palmate, but much larger. To the south of Guayaval other palms predominate, chiefly the pinnate-leaved _Piritu_ (_Guilielma speciosa_) and the _Mauritia flexuosa_, the sago-tree of America, which supplies farinaceous food, good wine, thread to weave into hammocks, clothes, and baskets; its fruit, in shape resembling pine-cones, being covered with scales, like those of _Calamus_ (Rotang), with something of the taste of an apple. The Guaranes, whose very existence, so to speak, depends on the Murichi palm, obtain an acid and very refreshing fermented liquor from it. This palm has large, shiny, corrugated, and fan-like leaves, maintaining a most beautiful verdure in times of the greatest drought. The sight of it alone in the Llanos produces an agreeable and refreshing sensation; and the Murichi, laden with its scaly fruit, contrasts singularly with the sad aspect of the palm of Cobija, the leaves of which are always gray and covered with dust.

If we ascend the Andes, between 20° south latitude and 5° north, at a height of from 5,000 to 10,000 feet above the sea level, we shall find extra-tropical forms of vegetation become more abundant: _Graminaceæ_; some _Amentaceæ_--such as the oaks, willows; _Labiatæ_; _Ericaceæ_; numerous _Compositæ_; _Caprifoliaceæ_; _Umbelliferæ_; _Rosaceæ_; _Cruciferæ_; and _Ranunculaceæ_. Tropical plants, on the contrary, disappear, or become very rare; but still, isolated species of palms, pepper-plants, _Cactaceæ_, passion-flowers, and _Melastomaceæ_ are found at considerable heights. Among the most abundant ligneous species are the _Ceroxylon andicola_, the highest of all the palms, which reaches the height of 200 feet, and produces a wax which exudes from its leaves, and from the base of their petioles; willow and Humboldt’s oak; several species of _Cinchona_, which here reign supreme; a few hollies, and species of _Andromeda_. Vegetables cultivated between the tropics, in Mexico, and as far south as the river Amazon, disappear almost entirely here; but maize and coffee, the cereals and European fruits, are cultivated in these regions; potatoes; _Chenopodium Quinoa_, the seeds of which, when boiled, serve as food for the inhabitants of the mountains.

If we ascend to the height of 10,000 feet above the sea on the Andes, and in the same latitude, tropical forms of vegetation almost entirely disappear. Those, on the contrary, which characterize temperate climates, and even the Polar regions, become abundant. Large trees are no longer seen. Alders, bilberries, currants; _Escallonia_, with bitter and tonic leaves, of which this is the home; hollies and _Drymis_, are bushes belonging to these regions, as well as the curious calceolarias, with shoe-shaped corolla, the seeds of which have supplied horticulture with an infinite number of varieties. Among the characteristic families we also find _Umbelliferæ_, _Caryophyllaceæ_, _Cruciferæ_, _Cyperaceæ_, mosses and lichens. Returning to more circumscribed botanical districts, the climate of Caracas has often been called one of perpetual spring. A more delicious temperature can not be conceived. During the day it ranges between 60° and 68° Fahr., and in the night between 60° and 64°, at once favorable to the growth of the banana, the orange, coffee, the apple, apricot, and wheat.

We must not quit these regions without mentioning two beneficent trees--the _Theobroma Cacao_ and the cow-tree, _Brosimum Galactodendron_. The roasted and crushed seeds of _Theobroma Cacao_, with the addition of sugar, make chocolate. Humboldt gives the following account of the cow-tree, which has the habit of _Chrysophyllum Cainito_: “The fruit is rather fleshy, consisting of one, sometimes two nuts. When incisions are made in the trunk an abundance of thick glutinous milk flows, which is without any acidity. This substance exhales a very agreeable balsam-like odor. It was presented to us in the fruit of the Calabash-tree. We drank considerable quantities of it in the evening before going to bed, and again early in the morning, without experiencing any injurious effects. Negroes and free people who work on the plantations drink of it, and soak their maize or manioc bread in it. The master of the farm assured us that the slaves fattened visibly during the season when the _Palo de Vacca_ furnishes them with most milk. Upon the arid flank of a rock,” adds Von Humboldt, “there grows a tree whose leaves are dry and coriaceous, its great ligneous roots almost piercing the stone. During many months of the year not a shower waters its foliage, the branches appear dry and dead; but when the trunk is pierced a sweet and nourishing milk follows the incision.”

In order to penetrate to the heart of the vegetation of Brazil, the region of palms and _Melastomaceæ_, the land of promise to the naturalists, we shall take as our guide Martius and August de Sainte-Hilaire, who have written with much exactness on the vegetable wonders displayed in the Brazilian forests. Their aspect varies according to the nature of the soil, and the distribution of water traversing them. If these forests are not the seat of a constant supply of moisture, or if the moisture is only renewed by periodical rains, the drought stops the vegetation, and it becomes intermittent, as in European climates. This is the case in the Catingas. The vegetation of the untrodden forests, on the contrary, of which Sainte-Hilaire gives an eloquent picture, is the reverse of this; excited by the ceaseless action of the two agents, humidity and heat, the vegetation of the virgin forests remains in a state of continual activity. The winter is only distinguished from the summer by a shade of color in the verdure of the foliage; and if some of the trees lose their leaves, it is to assume immediately a new appearance. “When a European arrives in America, and sees from a distance the untrodden forests for the first time, he is astonished not to see the singular forms which he admired in European hothouses, but which are here mingled in masses and lost. And he is astonished at the little difference in the outline of the forests between those of his own country and those of the New World, and he is only struck with the proportions and the deep green color of the leaves, which, under the most brilliant sky imaginable, impart a grave and severe aspect to the landscape. In order to appreciate all the beauties of the tropical forest we must plunge into retreats as old as the world. Nothing there reminds us of the fatiguing monotony of our oak and fir forests: each tree has a bearing peculiar to itself. Each has its own foliage, and often its own peculiar shade of verdure. Gigantic specimens of vegetation, each belonging to different, sometimes to remote, families, mingle their branches and blend their foliage. Five-leaved _Bignoniaceæ_ grow beside _Cæsalpinia_, and the golden leaves of _Cassia_ spread themselves in falling upon arborescent ferns. Myrtles and _Eugenia_, with their thousand-times-divided branches, are finely contrasted with the elegant simplicity of the palms; _Cecropia_ spreads its broad leaves and branches, which resemble immense candelabra, among the delicate foliage of _Mimosa_. There are trees with perfectly smooth bark, others are defended by prickly spines; and the enormous trunk of a species of wild fig spreads itself out with sloping plates, which seem to support it like so many arched buttresses. The obscure flowers of our beeches and oaks only attract the attention of naturalists; but in the forests of South America gigantic trees often display the most brilliant colors in their corolla. Long golden clusters hang from the branches of the _Cassia_. _Vochysia_ erect a thyrsus of odd-shaped flowers. Yellow and sometimes purple corollas, longer than those of our _Digitalis_, cover in profusion the species of trumpet-flowered _Bignonia_; and _Chorisia_ is decked with flowers which resemble our lily in shape, and remind us of _Alstromeria_ from the mixture of colors they present. Certain vegetable forms, which assume at home very humble proportions, present themselves with a floral pomp unknown in temperate climates; some _Boraginaceæ_ become shrubs; many _Euphorbiaceæ_ assume the proportions of majestic trees, offering an agreeable shelter under their thick umbrageous foliage.”

But it is principally among the _Graminaceæ_ that the greatest difference is observable. Of these there are a great number which attain no larger dimensions than our _Bromus_, forming masses of grass only distinguished from European species by their stems being more branchy, and the leaves larger. Others shoot up to the height of the forest tree, with a graceful habit. At first they are as upright as a lance, terminating in a point, with only one leaf, resembling a large scale, at each internode; when these fall, a crown of short branches springs from their axils, bearing the true leaves. The stems of the bamboos are thus decorated with verticils at regular intervals. It is to the _Lianes_ principally that tropical forests are indebted for their picturesque beauty, and these are the source of the most varied effects. Our own honeysuckle and the ivy give but a faint idea of the appearance presented by the crowd of climbing and creeping plants belonging to many different families. These are _Bignoniaceæ_, _Bauhinia_, _Cissus_, and _Hippocrateaceæ_, and while they all require a support, they each have notwithstanding a bearing peculiar to themselves. One of those climbing parasites will encircle the trunk of the largest trees to a prodigious height, the marks left by the old leaves seeming in their lozenge-shaped design to resemble the skin of a serpent. From this parasitic stem spring large leaves of a glossy green, while its lower parts give birth to slender roots, which descend again to the earth straight as a plumb-line. The tree which bears the Spanish name of _Cipo-Matador_, “the murderous Liane,” has a trunk so slight that it can not support itself alone, but must find support on a neighboring tree more robust than itself. It presses against its stem, aided by its aerial roots, which embrace it at intervals like so many flexible osiers, by which it secures itself and defies the most terrible hurricanes. Some _Lianes_ resemble waving ribbons, others are twisted in large spirals, or hang in festoons, spreading between the trees, and darting from one to another, twining round them, and forming masses of stem, leaves, and flowers, where the observer often finds it difficult to assign to each species what belongs to it.

Thousands of different species of shrubs, _Melastomaceæ_, _Boraginaceæ_, _peppers_, and _Acanthaceæ_, springing up round the roots of large trees, fill up the intervals left between them. Species of _Tillandsia_ and orchids, with flowers of strange and whimsical shape, make their appearance, and these often serve as supports to other parasites. Numerous brooks generally run through these forests, communicating their own freshness to the forest vegetation, presenting to the tired traveler delicious and limpid water, while the banks of the stream are carpeted with mosses, lycopodiums, and ferns, from the midst of which spring begonias, with delicate and succulent stems, unequal leaves, and flesh-colored flowers.

The forests of Paraguay, still little known, situated along the coast of the Atlantic, consist of ligneous _Compositæ_ and _Ilex paraguayensis_, the Paraguay tea, of which a large quantity is annually exported.

In the Argentine Republic Auguste de Saint-Hilaire found only 500 species of plants, among which only fifteen belonged to families which are not European.

When we reach the south coast of Patagonia and the Falkland Islands, a few brown and coriaceous _Graminaceæ_ and _Cyperaceæ_, such as _Dactylis cæspitosa_, _Carex trifida_, _Bolax glebaria_, _Cardamine glacialis_, _Veronica_, _Calceolaria_, _Aster_, _Opuntia Darwinii_, _Lomaria magellanica_ among the tree ferns, a few brambles, thickets of bilberries and _Arbutus_, include nearly the whole of the vegetation of these desert lands, where mosses, hepaticas, and lichens reign supreme. We now reach the southern part of South America. In the stormy region of Terra del Fuego thick forests cover the mountains, where they are sheltered from the wind, to the height of 1,500 feet above the level of the sea. _Fagus betuloides_ predominates there; then comes _F. antarctica_, accompanied by barberry and currant bushes.

At the Island of Hermite, the most southerly point of the American Continent, there is still some arborescent vegetation. Hooker there observed eighty-four flowering plants and many cryptogams. A fungus parasitic on the beech (_Cyttaria Gunnii_) constitutes there a principal aliment of the miserable inhabitants of these gloomy regions.

The Australian flora presents forms more ancient than any other contemporary vegetation. More than nine-tenths of the species found between 33° and 35° south latitude, in Australia, are absolutely limited to these regions. Many constitute completely distinct families; others form families which are scarcely represented in any other part of the globe. Those even which belong to groups more generally diffused disguise their natural affinities under forms isolated and unlike their congeners. The different species of two genera, namely, _Eucalyptus_ among _Myrtaceæ_, and _Acacia_ among _Leguminosæ_, form perhaps, from their number and dimensions, one-half of the vegetation which covers the country. Their leaves are reduced to phyllodes. Neither these phyllodes nor the limb of the real leaves are placed horizontally, like those of Europe and other parts of the world, but are perpendicular to the surface of the soil, so that the light shining between these vertical blades is not arrested, as in the case with our trees and bushes, in which the leaves are placed transversely one above the other. The effect produced by masses of Australian verdure is thus entirely different from that to which we are accustomed. The aspects of these forests particularly struck the first travelers who visited them, from the singular sensation communicated to the eye by this mode of distributing light and shade.