[14] p. 19.—“If the height of the aerial ocean and its pressure have not always been the same.”
The pressure of the atmosphere has a decided influence on the form and life of plants. From the abundance and importance of their leafy organs provided with porous openings, plants live principally in and through their surfaces; and hence their dependence on the surrounding medium. Animals are dependent rather on internal impulses and stimuli; they originate and maintain their own temperature, and, by means of muscular movement, their own electric currents, and the chemical vital processes which depend on and react upon those currents. A species of skin-respiration is an active and important vital function in plants, and this respiration, in so far as it consists in evaporation, inhalation, and exhalation of fluids, is dependent on the pressure of the atmosphere. Therefore it is that alpine plants are more aromatic, and are hairy and covered with numerous pores. (See my work über die gereizte Muskel- und Nervenfaser, Bd. ii. S. 142-145.) For according to Zoonomic experience, organs become more abundant and more perfect in proportion to the facility with which the conditions necessary for the exercise of their functions are fulfilled,—as I have elsewhere shown. In alpine plants the disturbance of their skin-respiration occasioned by increased atmospheric pressure makes it very difficult for such plants to flourish in the low grounds.
The question whether the mean pressure of the aerial ocean which surrounds our globe has always been the same is quite undecided: we do not even know accurately whether the mean height of the barometer has continued the same at the same place for a century past. According to Poleni’s and Toaldo’s observations, the pressure would have seemed to vary. The correctness of these observations has long been doubted, but the recent researches of Carlini render it almost probable that the mean height of the barometer is diminishing in Milan. Perhaps the phenomenon is a very local one, and dependent on variations in descending atmospheric currents.
[15] p. 20.—“Palms.”
It is remarkable that of this majestic form of plants,—(some of which rise to more than twice the height of the Royal Palace at Berlin, and to which the Indian Amarasinha gave the characteristic appellation of “Kings among the Grasses”),—up to the time of the death of Linnæus only 15 species were described. The Peruvian travellers Ruiz and Pavon added to these 8 more species. Bonpland and I, in passing over a more extensive range of country from 12° S. lat. to 21° N. lat., described 20 new species of palms, and distinguished as many more, but without being able to obtain complete specimens of their flowers. (Humboldt de distrib. geogr. Plantarum, p. 225-233.) At the present time, 44 years after my return from Mexico, there are from the Old and New World, including the East Indian species brought by Griffith, above 440 regularly described species. The Enumeratio Plantarum of my friend Kunth, published in 1841, had already 356 species.
A few, but only a few species of palms, are, like our Coniferæ, Quercineæ, and Betulineæ, social plants: such are the Mauritia flexuosa, and two species of Chamærops, one of which, the Chamærops humilis, occupies extensive tracts of ground near the Mouth of the Ebro and in Valencia; and the other, C. mocini, discovered by us on the Mexican shore of the Pacific and entirely without prickles, is also a social plant. While some kinds of palms, including Chamærops and Cocos, are littoral or shore-loving trees, there is in the tropics a peculiar group of mountain palms, which if I am not mistaken was entirely unknown previous to my South American travels. Almost all species of the family of palms grow on the plains or low grounds in a mean temperature of between 22° and 24° Reaumur (81°.5 and 86°, Fahr.); rarely ascending so high as 1900 English feet on the declivities of the Andes: but in the mountain palms to which I have alluded, the beautiful Wax-palm (Ceroxylon andicola), the Palmeto of Azufral at the Pass of Quindiu (Oreodoxa frigida), and the reed-like Kunthia montana (Caña de la Vibora) of Pasto, attain elevations between 6400 and 9600 English feet above the level of the sea, where the thermometer often sinks at night as low as 4°.8 and 6° of Reaumur (42°.8 and 45.°5, Fahr.), and the mean temperature scarcely amounts to 11° Reaumur, or 56°.8 Fahrenheit. These Alpine Palms grow among Nut trees, yew-leaved species of Podocarpus and Oaks (Quercus granatensis). I have determined by exact barometrical measurement the upper and lower limits of the range of the Wax-Palm. We first began to find it on the eastern declivity of Andes of Quindiu, at the height of 7440 (about 7930 English) feet above the level of the sea, and it extended upwards as far as the Garita del Paramo and los Volcancitos, or to 9100 (almost 9700 English) feet: several years after my departure from the country the distinguished botanist Don Jose Caldas, who had been long our companion amidst the mountains of New Granada, and who afterwards fell a victim to Spanish party hatred, found three species of palms growing in the Paramo de Guanacos very near the limits of perpetual snow; therefore probably at an elevation of more than 13000 (13855 English) feet. (Semanario de Santa Fé de Bogotá, 1809, No. 21, p, 163.) Even beyond the tropics, in the latitude of 28° North, the Chamærops martiana reaches on the sub-Himalayan mountains a height of 5000 English feet. (Wallich, Plantæ Asiaticæ, Vol. iii. Tab. 211.)
If we look for the extreme geographical limits of palms, (which are also the extreme climatic limits in all the species which inhabit localities but little raised above the level of the sea), we see some, as the date-palm, the Chamærops humilis, C. palmetto, and the Areca sapida of New Zealand, advance far into the temperate zones of either hemisphere, into regions where the mean temperature of the year hardly equals 11°.2 and 12°.5 Reaumur (57°.2, and 60°.2 Fahrenheit). If we form a series of cultivated plants or trees, placed in order of succession according to the degree of heat they require, and beginning with the maximum, we have Cacao, Indigo, Plantains, Coffee, Cotton, Date-palms, Orange and Lemon Trees, Olives, Sweet Chestnuts, and Vines. In Europe, date-palms (introduced, not indigenous) grow mingled with Chamærops humilis in the parallels of 43½° and 44°, as on the Genoese Rivera del Ponente, near Bordighera, between Monaco and San Stefano, where there is an assemblage of more than 4000 palm-stems; and in Dalmatia round Spalatro. It is remarkable that Chamærops humilis is abundant both at Nice and in Sardinia, and yet is not found in the island of Corsica which lies between those localities. In the New Continent, the Chamærops palmetto, which is sometimes above 40 English feet high, only advances as far North as 34° latitude, a difference sufficiently explained by the inflexions of the isothermal lines. In the Southern hemisphere, in New Holland, palms, of which there are very few, (six or seven species) only advance to 34° of latitude (see Robert Brown’s general remarks on the Botany of Terra Australis, p. 45); and in New Zealand, where Sir Joseph Banks first saw an Areca palm, they reach the 38th parallel. In Africa, which, quite contrary to the ancient and still widely prevailing belief, is poor in species of palms, only one palm, the Hyphæne coriacea, advances to Port Natal in 30° latitude. The continent of South America presents almost the same limits in respect to latitude. On the eastern side of the Andes, in the Pampas of Buenos Ayres and in the Cis-Plata province, palms extend, according to Auguste de St.-Hilaire, to 34° and 35° S. latitude. This is also the latitude to which on the western side of the Andes the Coco de Chile (our Jubæa spectabilis?), the only Chilian palm, extends, according to Claude Gay, being as far as the banks of the Rio Maule. (See also Darwin’s Journal, edition of 1845, p. 244 and 256).
I will here introduce some detached remarks which I wrote in March, 1801, on board the ship in which we were sailing from the palmy shores of the mouth of the Rio Sinu, west of Darien, to Cartagena de las Indias.
“We have now, in the course of the two years which we have spent in South America, seen 27 different species of palms. How many must Commerson, Thunberg, Banks, Solander, the two Forsters, Adanson, and Sonnerat, have observed in their distant voyages! Yet, at the present moment, when I write these lines, our systems of botany do not include more than from 14 to 18 systematically described species. In truth, the difficulty of procuring the flowers of palms is greater than can readily be imagined. We have felt it so much the more from having especially directed our attention to Palms, Grasses, Cyperaceæ, Juncaceæ, Cryptogamous Plants, and such other objects as have been least studied hitherto. Most species of palms flower only once a year, in the neighbourhood of the Equator in the months of January and February. But how often is it impossible for travellers to be precisely at that season in places where palms are principally found. In many species of palms the flowers last only so few days that one almost always arrives too late, and finds the fertilization completed and the male blossoms gone. Frequently only three or four species of palms are found in areas of 2000 square German geographical miles (3200 English geographical square miles). How is it possible during the short flowering season to visit the different places where palms abound: the Missions on the Rio Caroni, the Morichales at the mouth of the Orinoco, the valley of Caura and Erevato, the banks of the Atabapo and the Rio Negro, and the side of the Duida Mountain? Add to this the difficulty of reaching the flowers, when, in the dense forests, or on the swampy river banks, (as on the Temi and Tuamini), one sees them hanging from stems above 60 feet high, and armed with formidable spines. A traveller, when preparing to leave Europe on an expedition in which natural history is one of his leading objects, flatters himself with the thoughts of shears or curved blades fastened to long poles, with which he imagines he will be able to reach and cut down whatever he desires; he dreams, too, of native boys, who, with a cord fastened to their two feet, are to climb up the highest trees at his bidding. But, alas! very few of these fancies are ever realised; the great height of the blossoms renders the poles useless; and in the missions established on the banks of the rivers of Guiana, the traveller finds himself among Indians whose poverty, stoicism, and uncultivated state, renders them so rich, and so free from wants of every kind, that neither money nor other presents that can be made to them will induce them to turn three steps out of their path. This insurmountable apathy is the more provoking to a European, because he sees the same people climb with inconceivable agility wherever their own fancies lead them; for example, when they wish to catch a parrot, or an iguana, or a monkey, which having been wounded by their arrows saves himself from falling by holding on to the branches with his prehensile tail. Even at the Havannah we met with a similar disappointment. We were there in the month of January, and saw all the trees of the Palma Real (our Oreodoxa Regia), in the immediate vicinity of the city and on the public walks, adorned with snow-white blossoms. For several days we offered the negro boys whom we met in the streets of Regla and Guanavacoa two piastres for a single bunch of the blossoms which we wanted, but in vain! Between the tropics men are indisposed to laborious exertion, unless compelled by constraint or by extreme destitution. The botanists and artists of the Royal Spanish Commission for researches in Natural History, under the direction of Count Jaruco y Mopor (Estevez, Boldo, Guio, and Echeveria),—acknowledged to us that during several years they had not been able to obtain these flowers for examination. These difficulties sufficiently explain what would have been incomprehensible to me before my voyage, namely, that although during our two years’ stay up to the present time, we have, indeed, discovered more than 20 different species of palms, we have as yet been only able to describe systematically 12. How interesting a work might be produced by a traveller in South America who should occupy himself exclusively with the study of palms, and should make drawings of the spathe, spadix, inflorescence, and fruit, all of the size of nature!” (I wrote this many years before the Brazilian travels of Martius and Spix, and the admirable and excellent work of Martius on Palms.) “There is considerable uniformity in the shape of the leaves of palms; they are generally either pinnate (feathery, or divided like the plume of a feather);—or else palmate or palmo-digitate (of a fan-like form); the leaf-stalk (petiolus), is in some species without spines, in others sharply toothed (serrato-spinosus). The form of the leaf in Caryota urens and Martinezia caryotifolia, (which we saw on the banks of the Orinoco and Atabapo, and again in the Andes, at the pass of Quindiu, 3000 Fr. (3197 English) feet above the level of the sea), is exceptional and almost unique among palms, as is the form of the leaf of the Gingko among trees. The port and physiognomy of palms have a grandeur of character very difficult to convey by words. The stem, shaft, or caudex, is generally simple and undivided, but in extremely rare exceptions divides into branches in the manner of the Dracænas, as in Cucifera thebaica (the Doum-palm), and Hyphæne coriacea. It is sometimes disproportionately thick (as in Corozo del Sinu, our Alfonsia oleifera); sometimes feeble as a reed (as in Piritu, Kunthia montana, and the Mexican Corypha nana); sometimes swelling towards the base (as in Cocos); sometimes smooth, and sometimes scaly (Palma de covija o de sombrero, in the Llanos); sometimes armed with spines (as Corozo de Cumana and Macanilla de Caripe), the long spines being distributed with much regularity in concentric rings.
“Characteristic differences are also furnished in some species by roots which, springing from the stem at about a foot or a foot and a half above the ground, either raise the stem as it were upon a scaffolding, or surround it with thick buttresses. I have seen Viverras, and even very small monkeys, pass underneath this kind of scaffolding formed by the roots of the Caryota. Often the shaft or stem is swollen only in the middle, being more slender above and below, as in the Palma Real of the Island of Cuba. The leaves are sometimes of a dark and shining green (as in the Mauritia and the Cocoa nut palm); sometimes of a silvery white on the under side (as in the slender Fan-palm, Corypha miraguama, which we found in the Harbour of Trinidad de Cuba). Sometimes the middle of the fan or palmate leaf is ornamented with concentric yellowish or bluish stripes like a peacock’s tail; as in the thorny Mauritia which Bonpland discovered on the banks of the Rio Atabapo.
“The direction of the leaves is a character not less important than their form and colour. The leaflets (foliola), are sometimes arranged like the teeth of a comb, set on in the same plane, and close to each other, and having a very rigid parenchyma (as in Cocos, and in Phœnix the genus to which the Date belongs); whence the fine play of light from the sun-beams falling on the upper surface of the leaves (which is of a fresher verdure in Cocos, and of a more dead and ashy hue in the date palm); sometimes the leaves are flag-like, of a thinner and more flexible texture, and curl towards the extremities (as in Jagua, Palma Real del Sinu, Palma Real de Cuba, and Piritu dell’ Orinoco). The peculiarly majestic character of palms is given not only by their lofty stems, but also in a very high degree by the direction of their leaves. It is part of the beauty of any particular species of palms that its leaves should possess this aspiring character; and not only in youth, as is the case in the Date-palm, but also throughout the duration of the life of the tree. The more upright the direction of the leaves, or, in other words, the more acute the angles which they form with the upper part or continuation of the stem, the grander and more imposing is the general character and physiognomy of the tree. How different are the character and aspect given by the drooping leaves of the Palma de covija del Orinoco y de los Llanos de Calabozo (Corypha tectorum); the more nearly horizontal or at least less upright leaves of the Date and Cocoa-nut palms; and the aspiring heavenward pointing branches of the Jagua, the Cucurito, and the Pirijao!
“Nature has lavished every beauty of form on the Jagua palm, which, intermingled with the Cucurito or Vadgihai, (85 to 106 English feet high), adorns the cataracts of Atures and Maypures, and is occasionally found also on the lonely banks of the Cassiquiare. The smooth slender stems of the Jagua, rising to between 64 and 75 English feet, appear above the dense mass of foliage of other kinds of trees from amidst which they spring like raised colonnades, their airy summits contrasting beautifully with the thickly-leaved species of Ceiba, and with the forest of Laurineæ, Calophyllum, and different species of Amyris which surround them. The leaves of the Jagua, which are few in number (scarcely so many as seven or eight), are sixteen or seventeen feet long, and rise almost vertically into the air; their extremities are curled like plumes; the ultimate divisions or leaflets, having only a thin grass-like parenchyma, flutter lightly and airily round the slowly balancing central leaf-stalks. In all palms the inflorescence springs from the trunk itself, and below the place where the leaves originate; but the manner in which this takes place modifies the physiognomic character. In a few species only (as the Corozo del Sinu), the spathe (or sheath enclosing the flowers and fruits), rises vertically, and the fruits stand erect, forming a kind of thyrsus, like the fruits of the Bromelia: in most species of palms the spathes (which are sometimes smooth and sometimes rough and armed with formidable spines) are pendent; in a few species the male flowers are of a dazzling whiteness, and in such cases the flower-covered spadix, when fully developed, shines from afar. In most species of palms the male flowers are yellowish, closely crowded, and appear almost withered when they disengage themselves from the spathe.
“In Palms with pinnate foliage, the leaf-stalks either proceed (as in the Cocoa-nut, the Date, and the Palma Real del Sinu) from the dry, rough, woody part of the stem; or, as in the Palma Real de la Havana (Oreodoxa regia) seen and admired by Columbus, there rises upon the rough part of the stem a grass-green, smooth, thinner shaft, like a column placed upon a column, and from this the leaf-stalks spring. In fan-palms, “foliis palmatis,” the leafy crown (as in the Moriche and the Palma sombrero de la Havana) often rests on a previous bed of dry leaves, a circumstance which gives to the tree a sombre and melancholy appearance. In some umbrella-palms the crown consists of very few leaves, which rise upwards, carried on very slender petioles or foot-stalks (as in Miraguama).
“The form and colour of the fruits of Palms also offer much more variety than is commonly believed in Europe. Mauritia flexuosa bears egg-shaped fruits, whose scaly, brown, and shining surface, gives them something of the appearance of young fir-cones. What a difference between the enormous triangular cocoa-nut, the soft fleshy berries of the date, and the small hard fruits of the Corozo! But among the fruits of palms none equal in beauty those of the Pirijao (Pihiguao of S. Fernando de Atabapo and S. Balthasar); they are egg-shaped, mealy, and usually without seeds, two or three inches thick, and of a golden colour, which on one side is overspread with crimson; and these richly coloured fruits, crowded together in a bunch, like grapes, are pendent from the summits of majestic palm trees.” I have already spoken in the first volume of the present work, p. 216, of these beautiful fruits, of which there are seventy or eighty in a bunch, and which can be prepared as food in a variety of ways, like plantains and potatoes.
In some species of Palms the flower sheath, or spathe surrounding the spadix and the flowers, opens suddenly with an audible sound. Richard Schomburgk (Reisen in Britisch Guiana, Th. i. S. 55) has like myself observed this phenomenon in the flowering of the Oreodoxa oleracea. This first opening of the flowers of Palms accompanied by sound recalls the vernal Dithyrambus of Pindar, and the moment when, in Argive Nemea, “the first opening shoot of the date-palm proclaims the arrival of balmy spring.” (Kosmos, Bd. ii. S. 10; Eng. ed. p. 10.)
Three vegetable forms of peculiar beauty are proper to the tropical zone in all parts of the globe; Palms, Plantains or Bananas, and Arborescent Ferns. It is where heat and moisture are combined that vegetation is most vigorous, and its forms most varied; and hence South America excels the rest of the tropical world in the number and beauty of her species of Palms. In Asia this form of vegetation is more rare, perhaps because a considerable part of the Indian continent which was situated immediately under the equinoctial line has been broken up and covered by the sea in the course of former geological revolutions. We know scarcely anything of the palm trees of Africa between the Bight of Benin and the Coast of Ajan; and, generally speaking, we are only acquainted, as has been already remarked, with a very small number of species of Palms belonging to that quarter of the globe.
Palms afford, next to Coniferæ and species of Eucalyptus belonging to the family of Myrtaceæ, examples of the greatest loftiness of stature attained by any of the members of the vegetable kingdom. Of the Cabbage Palm (Areca oleracea), stems have been seen from 150 to 160 French (160 to 170 English) feet high. (Aug. de Saint-Hilaire, Morphologie végétale, 1840, p. 176.) The Wax-palm, our Ceroxylon andicola, discovered by us on the Andes between Ibague and Carthago, on the Montaña de Quindiu, attains the immense height of 160 to 180 French (170 to 192 English) feet. I was able to measure with exactness the prostrate trunks which had been cut down and were lying in the forest. Next to the Wax-palm, Oreodoxa Sancona, which we found in flower near Roldanilla in the Cauca Valley, and which affords a very hard and excellent building wood, appeared to me to be the tallest of American palms. The circumstance that notwithstanding the enormous quantity of fruits produced by a single Palm tree, the number of individuals of each species which are found in a wild state is not very considerable, can only be explained by the frequently abortive development of the fruits (and consequent absence of seeds), and by the voracity of their numerous assailants, belonging to all classes of the animal world. Yet although I have said that the wild individuals are not very numerous, there are in the basin of the Orinoco entire tribes of men who live for several months of the year on the fruits of palms. “In palmetis, Pihiguao consitis, singuli trunci quotannis fere 400 fructus ferunt pomiformes, tritumque est verbum inter Fratres S. Francisci, ad ripas Orinoci et Gauiniæ degentes, mire pinguescere Indorum corpora, quoties uberem Palmæ fructum fundant.” (Humboldt, de Distrib. geogr. Plant. p. 240.)
[16] p. 22.—“Since the earliest infancy of human civilisation.”
In all tropical countries we find the cultivation of the Banana or Plantain established from the earliest times with which tradition or history make us acquainted. It is certain that in the course of the last few centuries African slaves have brought new varieties to America, but it is equally certain that Plantains were cultivated in the new world before its discovery by Columbus. The Guaikeri Indians at Cumana assured us that on the Coast of Paria, near the Golfo Triste, when the fruits were allowed to remain on the tree till ripe, the plantain sometimes produced seeds which would germinate; and in this manner plantains are occasionally found growing wild in the recesses of the forest, from ripe seeds conveyed thither by birds. Perfectly formed seeds have also sometimes been found in plantain fruits at Bordones, near Cumana. (Compare my Essai sur la Géographie des Plantes, p. 29; and my Relat. hist. T. i. pp. 104 and 587, T. ii. pp. 355 and 367.)
I have already remarked elsewhere (Kosmos, Bd. ii. S. 191; English edition, p. 156), that Onesicritus and the other companions of Alexander, while they make no allusion to the tall arborescent ferns, speak of the fan-leaved umbrella palm, and of the delicate and always fresh verdure of the cultivated plantains or bananas. Among the Sanscrit names given by Amarasinha for the plantain or banana (the Musa of botanists) there are bhanu-phala (sun-fruit), varana-buscha, and moko. Phala signifies fruit in general. Lassen explains the words of Pliny (xii. 6), “arbori nomen palæ, pomo arienæ” thus: “The Roman mistook the word pala, fruit, for the name of the tree; and varana (in the mouth of a Greek ouarana) became transformed into ariena. The Arabic mauza may have been formed from moko, and hence our Musa. Bhanu-fruit is not far from banana-fruit.” (Compare Lassen, Indische Alterthumskunde, Bd. i. S. 262, with my Essai politique sur la Nouvelle Espagne, T. ii. p. 382, and Rel. hist. T. i. p. 491.)
[17] p. 22—“The form of Malvaceæ.”
Larger malvaceous forms begin to appear as soon as we have crossed the Alps; at Nice and in Dalmatia, Lavatera arborea; and in Liguria, Lavatera olbia. The dimensions of the Baobab, monkey-bread tree, have been mentioned above, (Vol. ii. p. 90.) To this form are attached the also botanically allied families of the Byttneriaceæ (Sterculia, Hermannia, and the large-leaved Theobroma Cacao, in which the flowers spring from the bark both of the trunk and the roots); the Bombaceæ (Adansonia, Helicteres, and Cheirostemon); and lastly the Tiliaceæ (Sparmannia Africana.) I may name more particularly as superb representatives of the Mallow-form, our Cavanillesia platanifolia, of Turbaco near Carthagena in South America, and the celebrated Ochroma-like Hand-tree, the Macpalxochiquahuitl of the Mexicans, (from macpalli, the flat hand), Arbol de las Manitas of the Spaniards, our Cheirostemon platanoides; in which the long curved anthers project beyond the fine purple blossom, causing it to resemble a hand or claw. Throughout the Mexican States this one highly ancient tree is the only existing individual of this extraordinary race: it is supposed to be a stranger, planted about five centuries ago by the kings of Toluca. I found the height above the sea where the Arbol de las Manitas stands to be 8280 French (8824 English) feet. Why is there only a single individual, and from whence did the kings of Toluca procure either the young tree or the seed? It seems no less difficult to account for Montezuma not having possessed it in his botanical gardens of Huaxtepec, Chapoltepec, and Iztapalapan, of which Hernandez, the surgeon of Philip II., was still able to avail himself, and of which some traces remain even to the present day; and it seems strange that it should not have found a place among the representations of objects of natural history which Nezahualcoyotl, king of Tezcuco, caused to be drawn half a century before the arrival of the Spaniards. It is asserted that the Hand-tree exists in a wild state in the forests of Guatimala. (Humboldt and Bonpland, Plantes équinoxiales, T. i. p. 82, pl. 24; Essai polit. sur la Nouv. Esp., T. i. p. 98.) At the equator we have seen two Malvaceæ, Sida Phyllanthos (Cavan), and Sida pichinchensis, ascend, on the mountain of Antisana and the Volcano Rucu-Pichincha, to the great elevations of 12600 and 14136 French (13430 and 15066 English) feet. (See our Plantes équin., T. ii. p. 113, pl. 116.) Only the Saxifraga boussingaulti (Brongn.) reaches, on the slope of the Chimborazo, an altitude six or seven hundred feet higher.
[18] p. 22.—“The Mimosa form.”
The finely feathered or pinnated leaves of Mimosas, Acacias, Schrankias, and species of Desmanthus, are most truly forms of tropical vegetation. Yet there are some representations of this form beyond the tropics; in the northern hemisphere in the Old Continent I can indeed cite but one, and that only in Asia, and a low-growing shrub, the Acacia Stephaniana, according to Kunth’s more recent investigations a species of the genus Prosopis. It is a social plant, covering the arid plains of the province of Shirwan, on the Kur (Cyrus), as far as the ancient Araxes. Olivier also found it near Bagdad. It is the Acacia foliis bipinnatis mentioned by Buxbaum, and extends as far north as 42° of latitude. (Tableau des Provinces situées sur la Côte occidentale de la Mer Caspienne, entre les fleuves Terek et Kour, 1798, pp. 58 and 120.) In Africa the Acacia gummifera of Willdenow advances as far as Mogador, or to 32° north latitude.
On the New Continent, the banks of the Mississipi and the Tennessee, as well as the savannahs of Illinois, are adorned with Acacia glandulosa (Michaux), and A. brachyloba (Willd). Michaux found the Schrankia uncinata extend northwards from Florida into Virginia, or to 37° N. latitude. Gleditschia tricanthos is found, according to Barton, on the east side of the Alleghany mountains, as far north as the 38th parallel, and on the west side even as far as the 41st parallel. Gleditschia monosperma ceases two degrees farther to the south. These are the limits of the Mimosa form in the northern hemisphere. In the southern hemisphere we find beyond the tropic of Capricorn simple leaved Acacias as far as Van Diemen Island; and even the Acacia cavenia, described by Claude Gay, grows in Chili between the 30th and 37th degrees of south latitude. (Molina, Storia Naturale del Chili, 1782, p. 174.) Chili has no true Mimosa, but it has three species of Acacia. Even in the north part of Chili the Acacia cavenia only grows to a height of twelve or thirteen feet; and in the south, near the sea coast, it hardly rises a foot above the ground. In South America, north of the equator, the most excitable Mimosas were (next to Mimosa pudica), M. dormiens, M. somnians, and M. somniculosa. Theophrastus (iv. 3) and Pliny (xii. 10) mention the irritability of the African sensitive plant; but I find the first description of the South American sensitive plants (Dormideras) in Herrera, Decad. II. lib. iii. cap. 4. The plant first attracted the attention of the Spaniards in 1518, in the savannahs on the isthmus near Nombre de Dios: “parece como cosa sensible;” and it was said that the leaves (“de echura de una pluma de pajaros”) only contracted on being touched with the finger, and not if touched with a piece of wood. In the small swamps which surround the town of Mompox on the Magdalena, we discovered a beautiful aquatic Mimosacea (Desmanthus lacustris). It is figured in our Plantes équinoxiales, T. i. p. 55, pl. 16. In the Andes of Caxamarca we found two Alpine Mimoseæ (Mimosa montana and Acacia revoluta), 8500 and 9000 French (about 9060 and 9590 English) feet above the surface of the Pacific.
Hitherto no true Mimosa (in the sense established by Willdenow), or even Inga, has been found in the temperate zone. Of all Acacias, the Oriental Acacia julibrissin, which Forskål has confounded with Mimosa arborea, is that which supports the greatest degree of cold. In the botanic garden of Padua there is in the open air a tree of this species with a stem of considerable thickness, although the mean temperature of Padua is below 10.°5 Reaumur (55°.6 Fahr.)
[19] p. 23—“Heaths.”
In these physiognomic considerations we by no means comprise under the name of Heaths the whole of the natural family of Ericaceæ, which on account of the similarity and analogy of the floral parts includes Rhododendron, Befaria, Gaultheria, Escallonia, &c. We confine ourselves to the highly accordant and characteristic form of the species of Erica, including Calluna (Erica) Vulgaris, L., the common heather.
While, in Europe, Erica carnea, E. tetralix, E. cinerea, and Calluna vulgaris, cover large tracts of ground from the plains of Germany, France, and England to the extremity of Norway, South Africa offers the most varied assemblage of species. Only one species which is indigenous in the southern hemisphere at the Cape of Good Hope, Erica umbellata, is found in the northern hemisphere, i. e. in the North of Africa, in Spain, and Portugal. Erica vagans and E. arborea also belong to the two opposite coasts of the Mediterranean: the first is found in North Africa, near Marseilles, in Sicily, Dalmatia, and even in England; the second in Spain, Italy, Istria, and in the Canaries. (Klotsch on the Geographical Distribution of species of Erica with persistent corollas, MSS.) The common heather, Calluna vulgaris, is a social plant covering large tracts from the mouth of the Scheldt to the western declivity of the Ural. Beyond the Ural, oaks and heaths cease together: both are entirely wanting in the whole of Northern Asia, and throughout Siberia to the shores of the Pacific Ocean. Gmelin (Flora Sibirica, T. iv. p. 129) and Pallas (Flora Rossica, T. i. Pars 2, p. 58) have expressed their astonishment at this disappearance of the Calluna vulgaris,—a disappearance which, on the eastern declivity of the Ural Mountains, is even more sudden and decided than might be inferred from the expressions of the last-named great naturalist. Pallas says merely: “ultra Uralense jugum sensim deficit, vix in Isetensibus campis rarissime apparet, et ulteriori Sibiriæ plane deest.” Chamisso, Adolph Erman, and Heinrich Kittlitz, have found Andromedas indeed in Kamtschatka, and on the North West coast of America, but no Calluna. The accurate knowledge which we now possess of the mean temperature of several parts of Northern Asia, as well as of the distribution of the annual temperature into the different seasons of the year, affords no sort of explanation of the cessation of heather to the east of the Ural Mountains. Joseph Hooker, in a note to his Flora Antarctica, has treated and contrasted with great sagacity and clearness two very different phenomena which the distribution of plants presents to us: on the one hand, “uniformity of surface accompanied by a similarity of vegetation;” and on the other hand, “instances of a sudden change in the vegetation unaccompanied by any diversity of geological or other features.” (Joseph Hooker, Botany of the Antarctic Voyage of the Erebus and Terror, 1844, p. 210.) Is there any species of Erica in Central Asia? The plant spoken of by Saunders in Turner’s Travels to Thibet (Phil. Trans. Vol. lxxix. p. 86), as having been found in the Highlands of Nepaul (together with other European plants, Vaccinium myrtillus and V. oxycoccus) and described by him as Erica vulgaris, is believed by Robert Brown to have been an Andromeda, probably Andromeda fastigiata of Wallich. No less striking is the absence of Calluna vulgaris, and of all the species of Erica throughout all parts of the Continent of America, while the Calluna is found in the Azores and in Iceland. It has not hitherto been seen in Greenland, but was discovered a few years ago in Newfoundland. The natural family of the Ericaceæ is also almost entirely wanting in Australia, where it is replaced by Epacrideæ. Linnæus described only 102 species of the genus Erica; according to Klotzsch’s examination, this genus really contains, after a careful exclusion of all mere varieties, 440 true species.
[20] p. 4.—“The Cactus form.”
If we take the natural family of the Opuntiaceæ separated from the Grossulariaceæ (the species of Ribes), and, viewed as it is by Kunth (Handbuch der Botanik, S. 609), we may well regard it as belonging exclusively to America. I am aware that Roxburgh, in the Flora Indica (inedita), cites two species of Cactus as belonging to South Eastern Asia;—Cactus indicus and C. chinensis. Both are widely disseminated, and are found in a wild state (whether they were originally wild or have become so), and are distinct from Cactus opuntia and C. coccinellifer; but it is remarkable that the Indian plant (Cactus indicus) has no ancient Sanscrit name. Cactus chinensis has been introduced in St. Helena as a cultivated plant. Now that a more general interest has at length been awakened on the subject of the original distribution of plants, future investigation will dispel the doubts which have been felt in several quarters respecting the existence of true Asiatic Opuntiaceæ. In the animal kingdom particular forms are found to occur singly. Tapirs were long regarded as a form exclusively characteristic of the New Continent; and yet the American tapir has been found as it were repeated in that of Malacca (Tapirus indicus, Cuv.)
Although the species of Cactus belong, generally speaking, more properly to the tropical regions, yet some are indigenous in the temperate zone, as on the Missouri and in Louisiana, Cactus missuriensis and C. vivipara; and Back saw with astonishment the shores of Rainy Lake, in north lat. 48° 40´, covered with C. opuntia. South of the equator the species of Cactus do not extend beyond the Rio Itata, in lat. 36°, and the Rio Biobio, in lat. 37° 15´. In the part of the Andes which is situated between the tropics, I have seen species of Cactus (C. sepium, C. chlorocarpus, C. bonplandii) growing on elevated plains nine or ten thousand (French) feet (about 9590 and 10660 English) above the level of the sea; but a still more alpine character is shewn in latitudes belonging to the temperate zone, in Chili, by the Opuntia ovallei, which has yellow flowers and a creeping stem. The upper and lower limits beyond which this plant does not extend have been accurately determined by barometric measurement by the learned botanist Claude Gay: it has never been found lower than 6330 French (6746 English) feet, and it reaches and even passes the limits of perpetual snow, having been found on uncovered masses of rock rising from amongst the snows. The last small plants were collected on spots situated 12820 French (13663 English) feet above the level of the sea. (Claudio Gay, Flora Chilensis, 1848, p. 30.) Some species of Echino-cactus are also true alpine plants in Chili. A counterpart to the fine-haired Cactus senilis is found in the thick-wooled Cereus lanatus, called by the natives Piscol, which has handsome red fruit. We found it in Peru, near Guancabamba, when on our journey to the Amazons river. The dimensions of the different kinds of Cactaceæ (a group on which the Prince of Salm-Dyck has been the first to throw great light) offer great variety and contrasts. Echinocactus wislizeni, which is 4 feet high and 7 feet in circumference (4 feet 3 inches and 7 feet 5 inches English), is still only the third in size, being surpassed by E. ingens (Zucc.) and by E. platyceras (Lem.) (Wislizenus, Tour to Northern Mexico, 1848, p. 97.) The Echinocactus stainesii reaches from 2 to 2½ feet diameter; E. visnago, from Mexico, upwards of 4 English feet high, is above 3 English feet diameter, and weighs from 700 to 2000 lbs.: while Cactus nanus, which we found near Sondorillo, in the province of Jaen, is so small that, being only slightly rooted in the sand, it gets between the toes of dogs. The Melocactuses, which are full of juice in the dryest seasons like the Ravenala of Madagascar (forest-leaf in the language of the country, from rave, raven, a leaf, and ala, the Javanese halas, a forest), are vegetable fountains; and the manner in which the horses and mules stamp them open with their hoofs, at the risk of injury from the spines, has been already mentioned (Vol. I p. 19). Since the last quarter of a century Cactus opuntia has extended itself in a remarkable manner into Northern Africa, Syria, Greece, and the whole of the South of Europe; even penetrating, in Africa, from the coasts far into the interior of the country, and associating itself with the indigenous plants.
When one has been accustomed to see Cactuses only in our hothouses, one is astonished at the degree of density and hardness which the ligneous fibres attain in old cactus stems. The Indians know that cactus wood is incorruptible, and excellent for oars and for the thresholds of doors. There is hardly anything in vegetable physiognomy which makes so singular and ineffaceable an impression on a newly arrived person, as the sight of an arid plain thickly covered, like those near Cumana, New Barcelona, and Coro, and in the province of Jaen de Bracamoros, with columnar and candelabra-like divided cactus stems.
[21] p. 24.—“Orchideæ.”
The almost animal shape of blossoms of Orchideæ is particularly striking in the celebrated Torito of South America (our Anguloa grandiflora); in the Mosquito (our Restrepia antennifera); in the Flor del Espiritu Santo (also an Anguloa, according to Floræ Peruvianæ Prodrom. p. 118, tab. 26); in the ant-like flower of the Chiloglottis cornuta (Hooker, Flora antarctica, p. 69); in the Mexican Bletia speciosa; and in the highly curious host of our European species of Ophrys: O. muscifera, O. apifera, O. aranifera, O. arachnites, &c. A predilection for this superbly flowering group of plants has so increased, that the number cultivated in Europe by the brothers Loddiges in 1848 has been estimated at 2360 species; while in 1843 it was rather more than 1650, and in 1813 only 115. What a rich mine of still unknown superb flowering Orchideæ the interior of Africa must contain, if it is well watered! Lindley, in his fine work entitled “The Genera and Species of Orchideous Plants,” described in 1840 precisely 1980 species; at the end of the year 1848 Klotzsch reckoned 3545 species.
While in the temperate and cold zones there are only “terrestrial” Orchideæ, i. e. growing on and close to the ground, tropical countries possess both forms, i. e. the “terrestrial” and the “parasitic,” which grow on trunks of trees. To the first-named of these two divisions belong the tropical genera Neottia, Cranichis, and most of the Habenarias. We have also found both forms growing as alpine plants on the slopes of the chain of the Andes of New Granada and Quito: of the parasitical Orchideæ (Epidendreæ), Masdevallia uniflora (at 9600 French, or about 10230 English feet); Cyrtochilum flexuosum (at 9480 French, or about 10100 English feet); and Dendrobium aggregatum (8900 French, or about 9480 English feet): and of the terrestrial Orchideæ, the Altensteinia paleacea, near Lloa Chiquito, at the foot of the Volcano of Pichincha. Claude Gay thinks that the Orchideæ said to have been seen growing on trees in the Island of Juan Fernandez, and even in Chiloe, were probably in reality only parasitical Pourretias, which extend at least as far south as 40° S. lat. In New Zealand we find that the tropical form of Orchideæ hanging from trees extends even to 45° S. lat. The Orchideæ of Auckland’s and Campbell’s Islands, however (Chiloglottis, Thelymitra, and Acianthus), grow on the ground in moss. In the animal kingdom, one tropical form at least advances much farther to the south. In Macquarie Island, in lat. 54° 39´, nearer to the South Pole therefore than Dantsic is to the North Pole, there is a native parrot. (See also the section Orchideæ in my work de Distrib. geogr. Plant., pp. 241-247.)
[22] p. 25.—“The Casuarinæ.”
Acacias which have phyllodias instead of leaves, some Myrtacesæ (Eucalyptus, Metrosideros, Melaleuca, and Leptospermum), and Casuarinas, give a uniform character to the vegetation of Australia and Tasmania (Van Diemen Island). Casuarinas with their leafless, thin, string-like, articulated branches, having the joints provided with membranous denticulated sheaths, have been compared by travellers, according to the particular species which fell under their observation, either to arborescent Equisetaceæ (Horsetails) or to our Scotch firs. (See Darwin, Journal of Researches, p. 449.) Near the coast of Peru the aspect of small thickets of Colletia and Ephedra also produced on my mind a singular impression of leaflessness. Casuarina quadrivalvis advances, according to Labillardière, to 48° S. lat. in Tasmania. The sad-looking Casuarina form is not unknown in India and on the east coast of Africa.
[23] p. 25.—“Needle-leaved trees.”
The family of Coniferæ holds so important a place by the number of individuals, by their geographical distribution, and by the vast tracts of country in the northern temperate zone covered with trees of the same species living in society, that we are almost surprised at the small number of species of which it consists,—even including members which belong to it in essential respects, but deviate from it in a degree by the shape of their leaves and their manner of growth (Dammara, Ephedra, and Gnetum, of Java and New Guinea). The number of known Coniferæ is not quite equal to three-fourths of the number of described species of palms; and there are more known Aroideæ than Coniferæ. Zuccarini, in his Beiträgen zur Morphologie der Coniferen (Abhandl. der mathem. physikal. Classe der Akademie der Wiss. zu München, Bd. iii. S. 752, 1837-1843), reckons 216 species, of which 165 belong to the northern and 51 to the southern hemisphere. Since my researches these proportionate numbers must be modified, as, including the species of Pinus, Cupressus, Ephedra, and Podocarpus, found by Bonpland and myself in the tropical parts of Peru, Quito, New Granada, and Mexico, the number of species between the tropics rises to 42. The most recent and excellent work of Endlicher, Synopsis Coniferarum, 1847, contains 312 species now living, and 178 fossil species found in the coal measures, the bunter-sandstone, the keuper, and the Jurassic formations. The vegetation of the ancient world offers to us more particularly forms which, by their simultaneous affinity with several different families of the present vegetable world, remind us that many intermediate links have perished. Coniferæ abounded in the ancient world: their remains, belonging to an early epoch, are found especially in association with Palms and Cycadeæ; but in the latest beds of lignite we also find pines and firs associated as now with Cupuliferæ, maples, and poplars. (Kosmos, Bd. i. S. 295-298, and 468-470; Engl. edit. p. 271-274, and lxxxix.)
If the earth’s surface did not rise to considerable elevations within the tropics, the highly characteristic form of needle-leaved trees would be almost unknown to the inhabitants of the equatorial zone. In common with Bonpland I have laboured much in the determination of the exact lower and upper limits of the region of Coniferæ and of oaks in the Mexican highlands. The heights at which both begin to grow (los Pinales y Encinales, Pineta et Querceta) are hailed with joy by those who come from the sea-coast, as indicating a climate where, so far as experience has hitherto shewn, the deadly malady of the black vomit (Vomito prieto, a form of yellow fever) does not reach. The lower limit of oaks, and more particularly of the Quercus xalapensis (one of the 22 Mexican species of oak first described by us), is on the road from Vera Cruz to the city of Mexico, a little below the Venta del Encero, 2860 (3048 E.) feet above the sea. On the western side of the highlands between the city of Mexico and the Pacific, the limit is rather lower down, for oaks begin to be found near a hut called Venta de la Moxonera, between Acapulco and Chilpanzingo, at an absolute elevation of 2328 (2480 E.) feet. I found a similar difference in the height of the lower limit of pine woods on the two-sides of the continent. On the Pacific side, in the Alto de los Caxones north of Quaxiniquilapa, we found this limit for Pinus Montezumæ (Lamb.), which we at first took for Pinus occidentalis (Swartz), at an elevation of 3480 (3709 E.) feet; while towards Vera Cruz, on the Cuesta del Soldado, pines are first met with at a height of 5610 (5950 E.) feet. Therefore both the kinds of trees spoken of above, oaks and pines, descend lower on the side of the Pacific than they do on the side of the Antillean sea. In ascending the Cofre di Perote, I found the upper limit of the oaks 9715 (10354 E.) feet, and that of the Pinus Montezumæ at 12138 (12936 E.) feet above the sea, or almost 2000 (2132 E.) feet higher than the summit of Etna. Considerable quantities of snow had fallen at this elevation in the month of February.
The more considerable the heights at which the Mexican Conifers are first met with, the more striking it appears to find in the Island of Cuba (where, indeed, on the borders of the torrid zone, northern breezes sometimes cool the atmosphere down to 6½° Reaumur, 46°.6 Fah.), another species of pine (P. occidentalis of Swartz), growing in the plains or on the low hills of the Isla de Pinos, intermixed with palms and mahogany trees (Swietenias). Columbus mentions a small pine wood (Pinal) in the journal of his first voyage (Diario del 25 de Nov. 1492), near Cayo de Moya, on the north-east of the Island of Cuba. In Hayti also, Pinus occidentalis descends from the mountains to the sea-shore, near Cape Samana. The trunks of these Pines, carried by the Gulf-stream to the Islands of Graciosa and Fayal in the Azores, were among the chief indications from which the great discoverer inferred the existence of unknown lands to the west. (See my Examen crit., T. ii. p. 246-259.) Is it true that in Jamaica, notwithstanding the height of its mountains, Pinus occidentalis is entirely wanting? We may also ask what is the species of Pinus found on the eastern coast of Guatimala, as P. tenuifolia (Benth.) probably belongs only to the mountains near Chinanta?
If we cast a general glance on the species which form the upper limits of arborescent vegetation in the northern hemisphere, from the frigid zone to the equator, we find, beginning with Lapland, that according to Wahlenberg, on the Sulitelma Mountain (lat. 68°) it is not needle-trees which form the upper limit, but that birches (Betula alba) extend much higher up than Pinus sylvestris;—whilst in the temperate zone, in the Alps (lat. 45¾°), Pinus picea (Du Roi) advances highest, leaving the birches behind; and in the Pyrenees (lat. 42½°), Pinus uncinata (Ram.) and P. sylvestris var. rubra: within the tropics, in lat. 19°-20° in Mexico, Pinus Montezumæ leaves far behind Alnus toluccensis, Quercus spicata, and Q. crassipes; while in the snow mountains of Quito at the equator, Escallonia myrtilloides, Aralia avicennifolia, and Drymis winteri, take the lead. The last-named tree, which is identical with Drymis granatensis (Mut.) and Wintera aromatica (Murray), presents, as Joseph Hooker has shewn (Flora Antarctica, p. 229), the striking example of the uninterrupted extension of the same species of tree from the most southern part of Tierra del Fuego and Hermit Island, where it was discovered by Drake’s Expedition in 1577, to the northern highlands of Mexico; or through a range of 86 degrees of latitude, or 5160 geographical miles. Where it is not birches (as in the far north), but needle trees (as in the Swiss Alps and the Pyrenees), which form the limit of arborescent vegetation on the highest mountains, we find above them, still nearer to the snowy summits which they gracefully enwreath with their bright garlands, in Europe and Western Asia, the Alp roses, the Rhododendra,—which are replaced on the Silla de Caracas and in the Peruvian Paramo de Saraguru by the purple flowers of another genus of Ericaceæ, the beautiful race of Befarias. In Lapland the needle-trees are immediately followed by Rhododendron laponicum; in the Swiss Alps by Rhododendron ferrugineum and R. hirsutum; in the Pyrenees by the R. ferrugineum only; and in the Caucasus by R. caucasicum. Decandolle found the Rhododendron ferrugineum growing singly in the Jura (in the Creux de Vent) at the moderate altitude of 3100 to 3500 (3304 to 3730 E.) feet, 5600 (5968 E.) feet lower down than its proper elevation. If we desire to trace the last zone of vegetation nearest to the snow line in the tropics, we must name, from our own observations, in the Mexican part of the tropical zone, Cnicus nivalis and Chelone gentianoides; in the cold mountain regions of New Granada, the woolly Espeletia grandiflora, E. corymbosa and E. argentea; and in the Andes of Quito, Culcitium rufescens, C. ledifolium, and C. nivale,—yellow flowering Compositæ which replace in the last-named mountains the somewhat more northerly Espeletias of New Granada, to which they bear a strong physiognomic resemblance. This replacement, the repetition of resembling or almost similar forms in countries separated either by seas or by extensive tracts of land, is a wonderful law of nature which appears to prevail even in regard to some of the rarest forms of vegetation. In Robert Brown’s family of the Rafflesieæ, separated from the Cytineæ, the two Hydnoras described by Thunberg and Drege in South Africa (H. africana and H. triceps) have their counterpart in South America in Hydnora americana (Hooker).
Far above the region of alpine plants, grasses, and lichens, and even above the limit of perpetual snow, the botanist sees with astonishment, both in the temperate and tropical zones, isolated phænogamous plants occur now and then sporadically on rocks which remain free from the general surrounding snowy covering, and which may possibly be warmed by heat ascending through open fissures. I have already spoken of the Saxifraga boussingaulti, which is found on the Chimborazo at an elevation of 14800 (15773 E.) feet; in the Swiss Alps, Silene acaulis has been seen at a height of 10680 (11380 E.) feet, being in the first-named case 600 (640 E.) feet, and in the second 2460 (2620 E.) feet above the limit of the snows, that limit being taken as it was in the two cases respectively at the time when the plants were found.
In our European Coniferæ, the Red and White Pine shew great and remarkable differences in respect to their distribution. While in the Swiss Alps the Red Pine (Pinus picea, Du Roi, foliis compresso—tetragonis; unfortunately called by Linnæus, and by most of the botanists of the present day, Pinus abies!) forms the upper limit of arborescent vegetation at a mean height of 5520 (5883 English) feet, only an occasional low growing mountain-alder (Alnus viridis, Dec., Betula viridis, Vill.) advancing now and then still nearer to the snow-line; the White Pine (Pinus abies, Du Roi, Pinus picea, Linn., foliis planis, pectinatodistichis, emarginatis) ceases, according to Wahlenberg, more than a thousand feet lower down. The Red Pine does not appear at all in the South of Europe, in Spain, the Appennines, and Greece; even on the northern slope of the Pyrenees it is seen only, as Ramond remarks, at great elevations, and is entirely wanting in the Caucasus. The Red Pine advances in Scandinavia farther to the north than the White Pine, of which last-named tree there is in Greece (on Mounts Parnassus, Taygetus, and Œta) a long needled variety (foliis apice integris, breviter mucronatis), the Abies Apollinis of Link. (Linnæa, Bd. xv. 1841, S. 529; and Endlicher, Synopsis Coniferarum, p. 96.)
On the Himalaya the Coniferæ are distinguished by the great thickness and height of their trunks, and by the length of their leaves. The Deodwara Cedar, Pinus deodara (Roxb.),—(properly, in Sanscrit, dêwa-dâru, timber of the Gods),—which is from 12 to 13½ feet thick, is the great ornament of the mountains. It grows in Nepaul to 11000 (11720 E.) feet above the level of the sea. More than 2000 years ago the Deodara supplied the materials for the fleet of Nearchus on the Hydaspes (the present Behut). In the valley of Dudegaon, north of the copper mines of Dhunpour in Nepaul, Dr. Hoffmeister, so early lost to science, found the Pinus longifolia of Royle (the Tschelu Pine) growing among tall stems of the Chamærops martiana of Wallich. (Hoffmeister’s Briefe aus Indien während der Expedition des Prinzen Waldemar von Preussen, 1847, S. 351.) Such an intermixture of pineta and palmata had excited the surprise of the companions of Columbus in the New Continent, as a friend and cotemporary of the Admiral, Petrus Martyr Anghiera, has informed us. (Dec. iii. lib. 10, p. 68.) I saw myself this intermixture of pines and palms for the first time on the road from Acapulco to Chilpanzingo. The Himalaya, like the Mexican highlands, has, besides Pines and Cedars, also the forms of Cypresses (Cupressus torulosa, Don), of Yews (Taxus wallichiana, Zuccar.), of Podocarpus (P. nereifolia, Robert Brown), and of Juniper (Juniperus squamata, Don., and J. excelsa, Bieberst; Juniperus excelsa is also found at Schipke in Thibet, in Asia Minor, in Syria, and in the Greek Islands). Thuja, Taxodium, Larix, and Araucaria, are forms found in the New Continent, but wanting in the Himalaya.
Besides the 20 species of Pines which we already know from Mexico, the United States of North America, which in their present extent reach to the Shores of the Pacific, have 45 described species, while Europe has only 15. There is a similar difference in respect to Oaks: i. e. greater variety of forms in the New Continent which extends continuously through a greater extent of latitude. The recent very exact researches of Siebold and Zuccarini have, however, completely refuted the previous belief, that many European species of Pines extend also across the whole of Northern Asia to the Islands of Japan, and even grow there, interspersed, as Thunberg has stated, with genuine Mexican species, the Weymouth Pine, Pinus Strobus of Linnæus. What Thunberg took for European Pines are wholly different and distinct species. Thunberg’s Red Pine (Pinus abies, Linn.) is P. polita, (Sieb.) and is often planted near Buddhistic temples; his common Scotch Fir (Pinus sylvestris) is P. Massoniana (Lamb.); his P. cembra (the German and Siberian pine with eatable seeds) is P. parviflora (Sieb.); his common Larch (P. larix) is P. leptolepis (Sieb.); and his supposed Taxus baccata, the fruits of which are eaten by Japanese courtiers in case of long-protracted court ceremonials, (Thunberg, Flora Japonica, p. 275), constitutes a distinct genus, and is the Cephalotaxus drupacea of Siebold. The Islands of Japan, notwithstanding the vicinity of the Continent of Asia, have a very distinct character of vegetation. Thunberg’s supposed Japanese Weymouth Pine, (Pinus Strobus) which would offer an important phenomenon, is only a planted tree, and is besides quite distinct from the American species of Pine. It is Pinus korajensis (Sieb.), and has been brought to Nipon from the peninsula of Corea, and from Kamtschatka.
Of the 114 species of the Genus Pinus with which we are at present acquainted, not one belongs to the Southern Hemisphere, for the Pinus merkusii described by Junghuhn and De Vriese belongs to the part of the Island of Sumatra which is north of the Equator, to the district of the Battas; and Pinus insularis (Endl.) although it was at first given in Loudon’s Arboretum as P. timoriensis, really belongs to the Philippines. Besides the Genus Pinus, the Southern hemisphere, according to the present state of our now happily advancing knowledge of the geography of plants, is entirely without species of Cupressus, Salisburia (Gingko), Cunninghamia (Pinus lanceolota, Lamb.) Thuja, (one of the species of which, Th. gigantea, Nutt., found on the banks of the Columbia, has a height of above 180 Eng. feet), Juniperus, and Taxodium (Mirbel’s Schubertia). I include the last-named genus with the less hesitation, as a Cape of Good Hope plant (Sprengel’s Schubertia capensis) is no Taxodium, but constitutes a genus of itself, Widringtonia, (Endl.) in quite a different division of the family of Coniferæ.
This absence, from the Southern Hemisphere, of true Abietineæ, Juniperineæ, Cupressineæ, and all the Taxodineæ, as well as of Torreya, Salisburia adiantifolia, and Cephalotaxus from among the Taxineæ, recalls forcibly the obscurity which still prevails in the conditions which have determined the original distribution of vegetable forms, a distribution which cannot be sufficiently and satisfactorily explained solely by similarity or diversity of soil, thermic relations, or meteorological phenomena. I remarked long ago that the Southern Hemisphere for example has many plants belonging to the natural family of Rosaceæ, but not a single species of the genus Rosa. We learn from Claude Gay that the Rosa chilensis described by Meyen is only a wild variety of the Rosa centifolia (Linn.), which has been for thousands of years a European plant. Such wild varieties, (i. e. varieties which have become wild) occupy large tracts of ground in Chili, near Valdivia and Osorno. (Gay, Flora Chilensis, p. 340.)
In the tropical region of the Northern hemisphere we also found only one single native rose, our Rosa montezumæ, in the Mexican highlands near Moran, at an elevation of 8760 (9336 Engl.) feet. It is one of the singular phenomena in the distribution of plants, that Chili, which has Palms, Pourretias, and many species of Cactus, has no Agave; although A. americana grows luxuriantly in Roussillon, near Nice, near Botzen and in Istria, having probably been introduced from the New Continent since the end of the 16th century, and in America itself forms a continuous tract of vegetation from Northern Mexico across the isthmus of Panama to the Southern part of Peru. I have long believed that Calceolarias were limited like Roses exclusively to one side of the Equator; of the 22 species which we brought back with us, not one was collected to the north of Quito and the Volcano of Pichincha; but my friend Professor Kunth remarks that Calceolaria perfoliata, which Boussingault and Captain Hall found at Quito, advances to New Granada, and that this species, as well as C. integrifolia of Santa Fé de Bogotá, were given by Mutis to the great Linnæus.
The species of Pinus which are so frequent in the tropical Antilles and in the tropical mountains of Mexico do not pass the isthmus of Panama, and are not found in the equally mountainous parts of the tropical portion of South America, and in the high plains of New Granada, Pasto, and Quito. I have been both in the plains and on the mountains from the Rio Sinu, near the isthmus of Panama, to 12° S. lat.; and in this tract of almost 1600 geographical miles the only forms of needle-trees which I saw were a Taxus-like species of Podocarpus with stems 60 (64 Eng.) feet high (Podocarpus taxifolia), growing in the Pass of Quindiu and in the Paramo de Saraguru, in 4° 26´ north, and 3° 40´ south latitude; and an Ephedra (E. americana) near Guallabamba, north of Quito.
Among the Coniferæ there are common to the northern and southern hemispheres the genera Taxus, Gnetum, Ephedra, and Podocarpus. The last-named genus was distinguished from Pinus long before L’Heritier by Columbus himself, who wrote on the 25th of November, 1492: “Pinales en la Serrania de Haiti que no llevan piñas, pero frutos que parecen azeytunos del Axarafe de Sevilla.” (See my Examen crit. T. iii. p. 24.) There are species of Taxus from the Cape of Good Hope to 61° N. lat. in Scandinavia, or through more than 95 degrees of latitude; Podocarpus and Ephedra extend almost as far. In Cupuliferæ, the species of oak which we are accustomed to regard as a northern form do not indeed pass beyond the equator in South America, but in the Indian Archipelago they re-appear in the southern hemisphere in the Island of Java. To the southern hemisphere belong exclusively ten genera of Coniferæ, of which I will name here only the principal: Araucaria, Dammara (Agathis Sal.), Frenela (with eighteen New Holland species), Dacrydium and Lybocedrus, which is found both in New Zealand and at the Straits of Magellan. New Zealand has one species of the genus Dammara (D. australis) and no Araucaria. In New Holland in singular contrast the case is opposite.
Among tree vegetation, it is in the form of needle-trees that Nature presents to us the greatest extension in length (longitudinal axis): I say among tree vegetation, because, as we have already remarked, among oceanic Algæ, Macrocystis pyrifera, which is found between the coast of California and 68° S. lat., often attains from 370 to 400 (about 400 to 430 Eng.) feet in length. Of Coniferæ, (setting aside the six Araucarias of Brazil, Chili, New Holland, Norfolk Island, and New Caledonia), the loftiest are those which belong to the northern temperate zone. As in the family of Palms we found the most gigantic, the Ceroxylon andicola, above 180 French (192 English) feet high, in the temperate mountain climate of the Andes, so the loftiest Coniferæ belong, in the northern hemisphere, to the temperate north-west coast of America and to the Rocky Mountains (lat. 40°-52°); and in the southern hemisphere to New Zealand, Tasmania or Van Diemen Island, the south of Chili and Patagonia (between 43° and 50° latitude). The most gigantic forms belong to the genera of Pinus, Sequoia (Endl.), Araucaria, and Dacrydium. I propose to name only those species which not only attain but often exceed 200 French feet (213 Eng.) In order to afford a standard of comparison, it should be remarked that in Europe the tallest Red and White Pines, the latter especially, attain about 150 or 160 (160-170 Eng.) feet; that, for example, in Silesia the Pine of the Lampersdorf Forest near Frankenstein enjoys great celebrity, although, with a circumference of 17 English feet, its height is only 153 Prussian, or 148 French, or 158 English feet. (Compare Ratzeburg, Forstreisen, 1844, S. 287.)
Pinus grandis (Douglas) in New California attains 224 English feet.
Pinus frémontiana (Endl.), also in New California, probably attains the same stature as the preceding. (Torrey and Frémont, Report of the Exploring Expedition to the Rocky Mountains in 1844, p. 319.)
Dacrydium cupressinum (Solander), from New Zealand, 213 English feet.
Pinus lambertiana (Dougl.), in North-west America, 224-235 English feet.
Araucaria excelsa (R. Brown), the Cupressus columnaris of Forster, in Norfolk Island and the surrounding rocky islets, 181-224 English feet. The six species of Araucaria which have become known to us hitherto, fall, according to Endlicher, into two groups:
a. The American group (Brazil and Chili): A. brasiliensis (Rich.), between 15° and 25° 8. lat.; and A. imbricata (Pavon), between 35° and 50° S. lat., the latter growing to 234-260 English feet.
b. The Australian group: A. bidwilli (Hook.) and A. cunninghami (Ait.) on the east side of New Holland; A. excelsa on Norfolk Island, and A. cookii (R. Brown) in New Caledonia. Corda, Presl. Göppert, and Endlicher, have already discovered five species of Araucarias belonging to the ancient world in the lias, in chalk, and in beds of lignite (Endlicher, Coniferæ fossiles, p. 301.).
Pinus Douglasii (Sabine), in the valleys of the Rocky Mountains and on the banks of the Columbia River (north lat. 48°-52°). The meritorious Scotch botanist from whom this tree is named perished in 1833 by a dreadful death in collecting plants in the Sandwich Islands, where he had arrived from New California. He fell inadvertently into a pit in which a fierce bull belonging to the cattle which have become wild had previously fallen, and was gored and trampled to death. By exact measurement a stem of Pinus Douglasii was 57½ English feet in girth at 3 feet above the ground, and its height was 245 English feet. (See Journal of the Royal Institution, 1826, p. 325.)
Pinus trigona (Rafinesque), on the western declivity of the Rocky Mountains, described in Lewis and Clarke’s Travels to the Source of the Missouri River and across the American Continent to the Pacific Ocean (1804-1806), 1814, p. 456. This gigantic Fir was measured with great care; the trunks were often 38 to 45 English feet in girth, 6 feet above the ground: one tree was 300 English feet high, and the first 192 feet were without any division into branches.
Pinus Strobus grows in the eastern parts of the United States of North America, especially on the east of the Mississipi; but it is found again in the Rocky Mountains from the sources of the Columbia to Mount Hood, or from 43° to 54° N. lat. It is called in Europe the Weymouth Pine and in North America the White Pine: its ordinary height does not exceed 160 to 192 Eng. feet, but several trees of 250 to 266 Eng. feet have been seen in New Hampshire. (Dwight, Travels, Vol. i. p. 36; and Emerson’s Report on the Trees and Shrubs growing naturally in the Forests of Massachusetts, 1846, p. 60-66.)
Sequoia gigantea (Endl.), Condylocarpus (Sal.) from New California; like Pinus trigona, about 300 English feet high.
The nature of the soil, and the circumstances of heat and moisture on which the nourishment of plants depend, no doubt influence the degree to which they flourish, and the increase in the number of individuals in a species; but the gigantic height attained by the trunks of a few among the many other nearly allied species of the same genus, depends not on soil or climate; but, in the vegetable as well as in the animal kingdom, on a specific organisation and inherent natural disposition. I will cite as the greatest contrast to the Araucaria imbricata of Chili, the Pinus Douglasii of the Columbia River, and the Sequoia gigantea of New California, which is from 245 to 300 Eng. feet in height,—not a plant taken from among a vegetation stunted by cold either of latitude or elevation, as is the case with the small Willow-tree, two inches in height, (Salix arctica),—but a small phænogamous plant belonging to the fine climate of the southern tropic in the Brazilian province of Goyaz. The moss-like Tristicha hypnoïdes, from the monocotyledonous family of the Podostemeæ, hardly reaches the height of 3 lines (27⁄100ths, or less than three-tenths of an English inch.) “En traversant le Rio Claro dans la Province de Goyaz,” says an excellent observer, Auguste de St.-Hilaire, “j’aperçus sur une pierre une plante dont la tige n’avoit pas plus de trois lignes de haut et que je pris d’abord pour une mousse. C’étoit cependant une plante phanérogame, le Tristicha hypnoïdes, pourvue d’organes sexuels comme nos chênes et les arbres gigantesques qui à l’entour élevaient leur cimes majestueuses.” (Auguste de St.-Hilaire, Morphologie Végétale, 1840, p. 98.)
Besides the height of their stems, the length, breadth, and position of the leaves and fruit, the form of the ramification aspiring or horizontal, and spreading out like a canopy or umbrella,—the gradations of colour, from a fresh green or silvery grey to a blackish-brown, all give to Coniferæ a peculiar physiognomy and character. The needles of Douglas’s Pinus lambertiana from North-west America are five French inches long; those of Pinus excelsa of Wallich, on the southern declivity of the Himalaya, near Katmandoo, seven French inches; and those of P. longifolia (Roxb.), from the mountains of Kashmeer, above a French foot long. In one and the same species the length of the leaves or needles varies in the most striking manner from the influence of soil, air, and elevation above the level of the sea. In travelling in an east and west direction through eighty degrees of longitude (above 3040 geographical miles), from the mouth of the Scheldt through Europe and the north of Asia to Bogoslowsk in the northern Ural and Barnaul beyond the Obi, I have found differences in the length of the needles of our common Fir (Pinus sylvestris) so great, that sometimes a traveller may be misled by the shortness and rigidity of the leaves, to think that he has discovered a new species allied to the Mountain Pine, P. rotundata (Link), P. uncinata (Ram.) Link has justly remarked (Linnæa, Bd. xv. 1841, S. 489) that such instances may be regarded as transitions to Ledebour’s P. sibirica of the Altai.
In the Mexican highlands I have looked with particular pleasure on the delicate cheerful green of the Ahuahuete, Taxodium distichum (Rich.), Cupressus disticha (Linn.), which, however, is much given to shedding its leaves. In this tropical region the above-mentioned tree, (of which the Aztec name signifies water-drum, from atl, water, and huehuetl, a drum, the trunk swelling to a great thickness), flourishes 5400 and 7200 (5755 and 7673 English) feet above the level of the sea, while in the United States of North America it is found in the low grounds of the cypress swamps of Louisiana, in the 43d parallel. In the Southern States of North America the Taxodium distichum (Cyprès chauve) reaches, as in the Mexican highlands, the height of 120 (128 English) feet, and the enormous thickness of 30 to 37 (32 to 39 English) feet, in diameter measured near the ground. (Emerson, Report on the Forests, pp. 49 and 101). The roots present the striking phenomenon of woody excrescences which project from 3 to 4½ feet above the earth, and are conical and rounded, and sometimes tabular. Travellers have compared these excrescences in places where they are very numerous to the grave tablets in a Jewish burying-ground. Auguste de St. Hilaire remarks with much acuteness:—“Ces excroissances du Cyprès chauve, ressemblant à des bornes, peuvent être regardées comme des exostoses, et comme elles vivent dans l’air, il s’en échapperoit sans doute des bourgeons adventifs, si la nature du tissu des plantes conifères ne s’opposoit au développement des germes cachés qui donnent naissance à ces sortes de bourgeons.” (Morphologie végétale, p. 91). A singularly enduring power of vitality in the roots of trees of this family is shown by a phenomenon which has excited the attention of vegetable physiologists, and appears to be of only very rare occurrence in other dicotyledonous trees. The remaining stumps of White Pines which have been cut down continue for several years to make fresh layers of wood, and to increase in thickness, without putting forth new shoots, leaves, or branches. Göppert believes that this only takes place by means of root nourishment received by the stump from a neighbouring living tree of the same species; the roots of the living individual which has branches and leaves having become organically united with those of the cut tree by their having grown together. (Göppert, Beobachtungen über das sogenannte Umwallen der Tannenstöcke, 1842, S. 12). Kunth, in his excellent new “Lehrbuch der Botanik,” objects to this explanation of a phenomenon which was known, imperfectly, so early as Theophrastus. (Hist. Plant. lib. iii. cap. 7, pp. 59 and 60, Schneider.) He considers the case to be analogous to what takes place when metal-plates, nails, carved letters, and even the antlers of stags, become enclosed in the wood of a growing tree. “The cambium, i. e. the viscid secretion out of which new elementary organs are constructed either of woody or cellular tissue, continues, without reference to the buds (and quite apart from them), to deposit new layers of wood on the outermost layer of the ligneous substance.” (Th. i. S. 143 and 166.)
The relations which have been alluded to, between elevation above the level of the sea and geographical and thermal latitude, manifest themselves often when we compare the tree vegetation of the tropical part of the chain of the Andes with the vegetation of the north-west coast of America, or with that of the shores of the Canadian Lakes. Darwin and Claude Gay have made the same remark in the Southern Hemisphere, in advancing from the high plains of Chili to Eastern Patagonia and Tierra del Fuego, where they found Drymis winteri and forests of Fagus antarctica and Fagus forsteri forming a uniform covering throughout long continuous lines running from north to south and descending to the low grounds. We find even in Europe small deviations (dependent on local causes which have not yet been sufficiently examined), from the law of constant ratio as regards stations or habitat of plants between elevation above the sea and geographical latitude. I would recall the limits, in respect to elevation, of the birch and the common fir in a part of the Swiss Alps, on the Grimsel. The fir (Pinus sylvestris) extends to 5940, and the birch (Betula alba) to 6480 French (6330 and 6906 English) feet; above the birches there is a higher line of Pinus cembra, whose upper limit is 6890 (7343 English) feet. Here, therefore, we have the birch intervening between two zones of Coniferæ. According to the excellent observations of Leopold Von Buch, and the recent ones of Martins, who also visited Spitzbergen, the following geographical limits were found in Lapland:—Pinus sylvestris extends to 70°; Betula alba to 70° 40´; and Betula nana quite up to 71°; Pinus cembra is altogether wanting in Lapland. (Compare Unger über den Einfluss des Bodens auf die Vertheilung der Gewächse, S. 200; Lindblom, Adnot. in geographicam plantarum intra Sueciam distributionem, p. 89; Martins, in the Annales des Sciences naturelles, T. xviii. 1842, p. 195).
If the length and arrangement of the needle-shaped leaves go far to determine the physiognomic character of Coniferæ, this character is still more influenced by the specific differences in the breadth of the needles, and the degree of development of the parenchyma of the appendicular organs. Several species of Ephedra may be called almost leafless; but in Taxus, Araucaria, Dammara (Agathis), and the Salisburia adiantifolia of Smith (Gingko biloba, Linn.), the surfaces of the leaves become gradually broader. I have here placed the genera in morphological succession. The specific names first chosen by botanists testify in favour of such a succession. The Dammara orientalis of Borneo and Java, often above ten feet in diameter, was first called loranthifolia; and Dammara australis (Lamb.) of New Zealand, which is 140 (149 English) feet high, was first called zamæfolia. In both these species of trees the leaves are not needles, but “folia alterna oblongo-lanceolata, opposita, in arbore adultiore sæpe alterna, enervia, striata.” The under surface of the leaves is thickly set with porous openings. This passage or transition of the appendicular system from the greatest contraction to a broad-leaved surface, like all progression from simple to compound, has at once a morphological and a physiognomic interest (Link, Urwelt, Th. I. 1834, S. 201-211). The short-stalked, broad, cleft leaf of the Salisburia (Kämpfer’s Gingko) has also its breathing pores only on the under side of the leaf. The original native country of this tree is unknown to us. By the connection and intercourse of Buddhistic communities it early passed from the temple-gardens of China to those of Japan.
In travelling from a port on the Pacific to Mexico, on our way to Europe, I witnessed the singular and painful impression which the first sight of a pine forest near Chilpanzingo made on one of our companions, who, born at Quito under the equinoctial line, had never seen needle trees, or trees with “folia acerosa.” It seemed to him as if the trees were leafless; and he thought that as we were travelling towards the cold North, he already recognised in this extreme contraction of the vegetable organs the chilling and impoverishing influence of the pole. The traveller whose impressions I here describe, whose name neither my friend Bonpland or myself can pronounce without regret, was Don Carlos Montufar (son of the Marquis of Selvalegre), an excellent young man, whose noble and ardent love of freedom led him a few years later, in the war of independence of the Spanish Colonies, to meet courageously a violent death, of which the dishonour did not fall on him.