Chapter XIV: Part 14

Larger forms of the Mallow appear, as soon as we have crossed the
Alps; _Lavatera arborea_, near Nice and in Dalmatia; and _L. olbia_,
in Liguria. The dimensions of the Baobab (monkey bread-tree) have
already been given. (See pp. 270–272.) With the form of the Malvaceæ
are associated the botanically allied families of the Byttneriaceæ,
(_Sterculia_, _Hermannia_, and the blossoms of the large-leaved
_Theobroma Cacao_, whose flowers break forth from the bark of the
trunk as well as from the roots); the Bombaceæ (_Adansonia_,
_Helicteres_, and _Cheirostemon_); and, lastly, the Tiliaceæ
(_Sparmannia Africana_). Our _Cavanillesia plantanifolia_ of Turbaco,
near Carthagena in South America, and the celebrated Ochroma-like
Hand-tree, the _Macpalxochiquahuitl_ of the Mexicans, (from Macpalli,
the flat of the hand,) _Arbol de las manitas_ of the Spaniards, our
_Cheirostemon platanoides_, are splendid representatives of the mallow
form. In the last named, the anthers are connected together in such a
manner as to resemble a hand or claw rising from the beautiful
purplish-red blossoms. There is in all the Mexican free states only
one individual remaining, one single primæval stem of this wonderful
genus. It is supposed not to be indigenous, but to have been planted
by a king of Toluca, about five hundred years ago. I found that the
spot where the Arbol de las Manitas stands is 8825 feet above the
level of the sea. Why is there only one tree of the kind? Whence did
the kings of Toluca obtain the young tree or the seed? It is equally
enigmatical, that Montezuma should not have possessed one of these
trees in his botanical gardens of Huaxtepec, Chapoltepec, and
Iztapalapan, which were used as late as by Philip the Second’s
physician, Hernandez, and of which gardens traces still remain; and it
appears no less striking that the Hand-tree should not have found a
place among the drawings of subjects connected with natural history,
which Nezahual Coyotl, king of Tezcuco, caused to be made, half a
century before the arrival of the Spaniards. It is asserted that the
Hand-tree grows wild in the forests of Guatimala.[OI] We found two
Malvaceæ, _Sida Phyllanthos_ (Cavan.), and _Sida Pichinchensis_,
rising in the equatorial region to the great height of 13,430, and
15,066 feet on the mountain of Antisana and at the volcano of Rucu
Pichincha.[OJ] The _Saxifraga Boussingaultii_ rises from 600 to
upwards of 700 feet higher, on the declivity of Chimborazo.

Footnote 88:

p. 225—“_Form of the Mimosæ_.”

The delicate and feathery foliage of the Mimosæ, Acaciæ, Schrankiæ,
and Desmanthus, may be regarded as peculiarly characteristic of
tropical vegetation; although some representatives of this form may
also be found without the tropics. In the Old Continent of the
northern hemisphere, and indeed in Asia, I can instance only one low
shrub, described by Marshal von Bieberstein as _Acacia Stephaniana_,
but which, according to Kunth’s more recent investigations, is a
species of the genus _Prosopis_. This social plant covers the arid
plains of the province of Schirvan on the Kur (Cyrus), near New
Schamach, as far as the ancient Araxes. Olivier found it also in the
neighbourhood of Bagdad. It is the _Acacia foliis bipinnatis_
mentioned by Buxbaum, and which extends towards the north as far as
42° lat.[OK] In Africa the _Acacia gummifera_ (Willd.), extends to
Mogador, and therefore as far as 32° north lat.

In the New Continent, _Acacia glandulosa_ (Michaux), and _A.
brachyloba_ (Willd.), adorn the banks of the Mississippi and
Tennessee, and the Savannahs of the Illinois. The _Schrankia uncinata_
was found by Michaux to penetrate from Florida northwards to Virginia
(therefore as far as 37° north lat.). _Gleditschia triacanthos_ is met
with, according to Barton, to the east of the Alleghany mountains, as
far as 38° north lat., and west of the same range even to 41° north
lat. The extreme northern limit of _Gleditschia monosperma_ is two
degrees further southward. Such are the boundaries of the Mimosa form
in the northern hemisphere, while in the southern hemisphere, beyond
the tropic of Capricorn, simple-leaved Acaciæ are found as far as Van
Dieman’s Land; the Acacia cavenia described by Claude Gay being even
found in Chili between 30° and 37° south lat.[OL] Chili has no true
Mimosa, but three species of Acacia; and even in the north of Chili
the Acacia cavenia grows only to a height of 12 or 13 feet, whilst in
the south, as it approaches the sea-coast, it scarcely rises a foot
above the ground. The most sensitive of the Mimosas which we saw in
the northern portion of South America, are (next to the Mimosa
pudica,) _M. dormiens_, _M. somnians_, and _M. somniculosa_. The
irritability of the African sensitive plant was already noticed by
Theophrastus (iv. 3), and by Pliny (xiii. 10); 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
round Nombre de Dios (“parece como cosa sensible”), and it was
pretended that the leaves (“de echura de una pluma de pajaros,”) only
contracted together when they were touched with the finger, and not
when brought in contact with a piece of wood. In the small swamps
which surround the town of Mompox on the Magdalena River, we
discovered a very beautiful aquatic Mimosa (_Desmanthus lacustris_), a
representation of which is given in our “Plantes équinoxiales” (t. i.
p. 55, pl. 16). In the chain of the Andes of Caxamarca we found two
Alpine Mimosas (Mimosa montana and Acacia revoluta) growing at
elevations of from 9000 to nearly 9600 feet above the level of the
sea.

As yet no true Mimosa, (in the meaning of the word as established by
Willdenow,) nor even any Inga, has been found in the temperate zone.
Amongst all the Acacias the Oriental _Acacia Julibrissin_, which
Forskäl has confounded with _Mimosa arborea_, endures the greatest
degree of cold. In the Botanical Garden of Padua there is a high stem
of considerable thickness growing in the open air, although the mean
temperature of Padua is below 56° Fahrenheit.

Footnote 89:

p. 225.—“_Heaths_.”

We do not, in these physiognomical considerations, by any means
comprehend, under the name of Heaths, the whole natural family of the
Ericaceæ, which, on account of the similarity and analogy in the
flowering parts of the plant, include Rhododendrum, Befaria,
Gaultheria, and Escallonia; we limit ourselves to the very accordant
and characteristic form of the species of Erica, including Calluna
(_Erica vulgaris_, L.).

“Whilst in Europe Erica carnea, E. tetralix, E. cinerea, and Calluna
vulgaris, cover large tracts of country, extending from the plains of
Germany, and from France and England, to the extremity of Norway;
Southern Africa presents the most varied assortment of species. One
single species, Erica umbellata, which is indigenous in the southern
hemisphere, at the Cape of Good Hope, is again found in Northern
Africa, Spain, and Portugal. Erica vagans and E. arborea also belong
to the opposite coasts of the Mediterranean. The former is met with in
Northern Africa, in the neighbourhood of Marseilles, in Sicily and
Dalmatia, and even in England; the second in Spain, Istria, Italy, and
the Canaries.”[OM] The common heath, _Calluna vulgaris_ (Salisbury),
which is a social plant, covers large tracts from the mouth of the
Scheldt to the western declivity of the Ural. Beyond the Ural both
Oaks and Heaths disappear. Both are wanting in the whole of Northern
Asia, and in all Siberia, as far as the Pacific. Gmelin[ON] and
Pallas[OO] have expressed their astonishment at this disappearance of
Calluna vulgaris; which, on the eastern declivity of the Ural chain is
even more decided and more sudden than one might be led to conclude,
from the words of the last-named great naturalist. Pallas merely says,
“ultra Uralense jugum sensim deficit, vix in Isetensibus campis
rarissime apparet, et ulteriori Sibiriæ plane deest.” Chamisso, Adolph
Erman, and Heinrich Kittlitz collected Andromedas but no Calluna in
Kamtschatka and on the north-west coast of America. The accurate
knowledge which we at present possess of the mean temperature of
different portions of Northern Asia, as well as of the distribution of
annual heat throughout the different seasons, in no way explains the
non-advance of the Heath to the east of the Ural. Dr. Joseph Hooker
has treated with much ingenuity, in a note to his “Flora Antarctica,”
of the two contrasting phenomena of the distribution of plants,
“uniformity of surface accompanied by a similarity of vegetation”, and
again, “instances of a sudden change in the vegetation, unaccompanied
with any diversity of geological and other feature.”[OP] Is there an
Erica in Central Asia? That which Saunders, in Turner’s “Travels to
Thibet,”[OQ] has described in the highlands of Nepaul, besides other
European plants (Vaccinium Myrtillus, and V. oxycoccus), as Erica
vulgaris, is, according to the opinion communicated to me by Robert
Brown, probably the Andromeda fastigiata of Wallich. The absence of
Calluna vulgaris and of all species of Erica, throughout the whole of
the continental part of America is an equally striking fact, since
Calluna is met with in the Azores and in Iceland. It has not hitherto
been found in Greenland, but it was discovered some years ago in
Newfoundland. The natural family of the Ericaceæ is also almost
entirely wanting in Australia, where its place is supplied by the
Epacrideæ. Linnæus described only 102 species of the genus Erica, but,
according to Klotzsch’s observations, this genus comprises 440 true
species, after the varieties have been carefully excluded.

Footnote 90:

p. 226—“_The Cactus form_.”

When the natural family of the Opuntiaceæ is separated from the
Grossulariaceæ (species _Ribes_), and is confined within the limits
indicated by Kunth,[OR] we may regard the whole as exclusively
American. I am not ignorant, that Roxburgh, in the _Flora indica_
(inedita), mentions two species of Cactus which he regards as peculiar
to the south-east of Asia, viz., Cactus indicus, and C. chinensis.
Both are widely diffused, originally wild or having become so, and
different from Cactus opuntia and C. Coccinellifer; but it is
remarkable that this Indian plant should have no ancient Sanscrit
name. The so-called Chinese Cactus has been introduced by cultivation
into the island of St. Helena. Modern investigations, prosecuted at a
period when a more general interest has been awakened in relation to
the original distribution of plants, will unquestionably remove the
doubts that have frequently been advanced against the existence of
Asiatic Opuntiaceæ. We see, in a similar manner, certain vital forms
appear separately in the animal world. How long did the Tapir continue
to be regarded as a characteristic form of the New Continent! And yet
the American Tapir is, as it were, repeated in that of Malacca
(_Tapirus indicus_, Cuv.).

Although the Cactus form belongs, properly speaking, to the tropical
regions, there are some species in the New Continent, that are
indigenous to the temperate zone on the Missouri and in Louisiana; as,
for instance, Cactus missuriensis and C. vivipara. Back, in his
northern expedition, saw with astonishment, the banks of the Rainy
Lake in lat. 48° 40′ (long. 92° 53′) entirely covered with C. Opuntia.
South of the equator the Cactus does not advance further than Rio
Itata (lat. 36°) and Rio Biobio (lat. 37¼°) In the part of the chain
of the Andes lying within the tropics, I have found species of Cactus
(_C. sepium_, _C. chlorocarpus_, _C. bonplandii_) on elevated plains
from 9000 to upwards of 10,600 feet above the level of the sea; but in
Chili, in the temperate zone, a far more strongly marked Alpine
character is exhibited by Opuntia Ovallei, whose upper and lower
limits have been accurately determined through barometric measurements
by the learned botanist, Claude Gay. The yellow-flowering Opuntia
Ovallei, which has a creeping stem, does not descend below 6746 feet,
advancing as high as the line of perpetual snow; and even above it,
wherever a few masses of rock remain uncovered. These little plants
have been gathered at spots lying at an elevation of 13,663 feet above
the level of the sea.[OS] Some species of Echinocactus are also true
alpine plants in Chili. A counterpart to the much admired fine-haired
Cactus senilis is presented by the thick-wooled Cereus lanatus, called
by the natives _Piscol_, which has a fine red fruit. We found it near
Guancabamba, in Peru, on our journey to the Amazon river. The
dimensions of the Cactaceæ (a group on which the Prince of Salm-Dyck
was the first to throw considerable light) present the most striking
contrasts. Echinocactus Wislizeni, which has a circumference of seven
feet and a half, with a height of four feet and a quarter, is only
third in size, being surpassed by E. ingens, (Zucc.) and E.
platyceras. (Lem.)[OT] The Echinocactus Stainesii attains a diameter
of from two feet to two and a-half; E. visnago, belonging to Mexico,
has a diameter of upwards of three feet, with a height of more than
four feet, and weighs as much as from 700 to 2000 lbs.; while the
Cactus nanus, which we collected near Sondorillo, in the province of
Jaen, is so small and so loosely rooted in the sand, that it gets
between the toes of dogs. The Melocactuses, which are full of juice
even in the driest season, as the Ravenala of Madagascar (wood-leaf in
the language of the country from _rave_, _raven_, a leaf, and _ala_,
the Javanese _halas_, a wood), are vegetable springs, which the wild
horses and mules open by stamping with their hoofs—a process in which
they frequently injure themselves.[OU] Cactus Opuntia has spread
during the last quarter of a century in a remarkable manner through
Northern Africa, Syria, Greece, and the whole of Southern Europe;
penetrating from the coasts of Africa far into the interior, where it
associates with the native plants.

After being accustomed to see Cactuses only in our hothouses, we were
astonished at the density of the woody fibres in old cactus stems. The
Indians are aware that cactus wood is indestructible, and admirably
adapted for oars and the thresholds of doors. There is hardly any
physiognomical character of exotic vegetation that produces a more
singular and ineffaceable impression on the mind of the traveller,
than an arid plain densely covered with columnar or candelabra-like
stems of cactuses, similar to those near Cumana, New Barcelona, Coro,
and in the province of Jaen de Bracamoros.

Footnote 91:

p. 226—“_Orchideæ_.”

The almost animal-like form occasionally observed in blossoms of the
Orchideæ is most strongly marked in Anguloa grandiflora, celebrated in
South America as the Torito; in the Mosquito (our Restrepia
antennifera); in the Flor del Espiritu Santo (likewise an Anguloa,
according to _Floræ Peruvianæ Prodrom._ p. 118, tab. 26); in the
ant-like flower of Chiloglottis cornuta;[OV] in the Mexican Bletia
speciosa; and in the whole host of our remarkable European species of
Ophrys: _O. muscifera_, _O. apifera_, _O. aranifera_, _O. arachnites_,
_&c._ The taste for these splendidly flowering plants has so much
increased, that the number of species cultivated by Messrs. Loddige,
which, in 1813, was only 115, was upwards of 1650 in 1843, and in
1848, the number was estimated at no fewer than 2360. What a treasure
of sumptuously flowering and unknown Orchideæ may be inclosed in the
interior of Africa wherever there is an abundant supply of water!
Lindley, in his beautiful work, _On the Genera and Species of
Orchideous Plants_, 1840, counted exactly 1980 species; whilst
Klotzsch at the close of the year 1848 counted 3545.

Whilst the temperate and cold zone possess only terrestrial Orchideæ,
growing close to the ground, both forms, the terrestrial, as well as
the parasitical, growing on the trunks of trees, are indigenous in the
beautiful regions of the tropics. To the former class belong the
tropical genera Neottia, Cranichis, and most Habenarias. But we have
found both these forms as alpine plants on the declivity of the Andes
of New Granada and Quito, viz., the parasitical (_Epidendreæ_)
Masdevallia uniflora (at an elevation of 10,231 feet), Cyrtochilum
flexuosum (at 10,103 feet), and Dendrobium aggregatum (at 9485 feet);
and the terrestrial forms of Altensteinia paleacea, near Lloa
Chiquito, at the foot of the volcano of Pichincha. Claude Gay is of
opinion that the Orchideæ supposed to have been found growing on trees
in the Island of Juan Fernandez and even at Chiloe, were probably only
parasitical Pourretiæ, which advance as far south at least as 40°. In
New Zealand, the tropical form of Orchideæ, hanging from trees, is
still to be seen as far south as 45°. But the Orchideæ of Auckland and
Campbell Islands (Chiloglottis, Thelymitra, and Acianthus), grow on
level ground in moss. In the animal world there is at least one
tropical form that penetrates further south. The Island of Macquarie
(lat. 54° 39′) has an indigenous parrot, which lives therefore in a
region nearer to the south pole than Danzig is to the north pole.[OW]

Footnote 92:

p. 226—“_Form of the Casuarinæ_.”

Acacias, in which the place of the leaves is supplied by phyllodia,
Myrtaceæ (Eucalyptus, Metrosideros, Melaleuca, Leptospermum), and
Casuarinæ, constitute the sole characteristics of the vegetable world
of Australia (New Holland) and Tasmania (Van Diemen’s Land). Casuarinæ
with their leafless, thin, thread-like, articulated branches, and
their joints furnished with membranous, toothed spathes, have been
compared by travellers,[OX] according to differences of species,
either with arborescent Equisetaceæ (Horsetails) or with our Scotch
firs. I have been much struck with the singular appearance of
leaflessness presented by the small thickets of Colletia and Ephedra
in South America, near the coast of Peru. Casuarina quadrivalvis
penetrates, according to Labillardière, as far south as 43° in
Tasmania. The mournful form of the Casuarina is not unknown in the
East Indies and even on the eastern coast of Africa.

Footnote 93:

p. 227—“_Acicular-leaved trees_.”

The family of the Coniferæ (including the genera of Dammara, Ephedra,
and Gnetum of Java and New Guinea, which are essentially allied to it,
though distinctly separated by the form of the leaf and the whole
conformation), plays so important a part in consequence of the number
of individuals in each species, and by its geographical diffusion,
while it covers in the northern temperate zone, as a social plant,
such extensive districts, that we are almost compelled to wonder at
the inconsiderable number of the species. We are not acquainted with
so many Coniferæ by three-fourths as there are Palms already
described, nay, the Coniferæ are numerically less than the Aroideæ.
Zuccarini, in his “Contributions to the Morphology of the
Coniferæ,”[OY] enumerates 216 species, of which 165 belong to the
Northern and 51 to the Southern hemisphere. These proportional numbers
must now, in consequence of my researches, be differently expressed,
since, with the species of Pinus, Cupressus, Ephedra, and Podocarpus,
which Bonpland and I discovered in the tropical part of Peru, Quito,
New Granada, and Mexico, the number of the cone-bearing trees
flourishing between the tropics amounts to 42. The excellent and
latest work of Endlicher[OZ] contains 312 species of Coniferæ now
living, and 178 of a primeval mundane period which are now buried in
the coal formation, in variegated sandstone, in keuper, and in Jura
limestone. The vegetation of the eocene world presents especially to
us forms which, by their coëval relationship with several families of
the present world, remind us that with it many intervening members
have disappeared. The Coniferæ, so frequent in the primeval world,
accompany, in particular, the ligneous remains of Palms and Cycadeæ;
but in the most recent beds of lignite or brown coal we again find
Coniferæ, our Pines and Firs, associated with Cupuliferæ (or
Mastworts), Maples and Poplars.[PA]

If the surface of the earth did not rise to great altitudes within the
tropics, the strikingly characteristic form of acicular-leaved trees
would have remained wholly unknown to the inhabitants of that zone. I
took great pains, in common with Bonpland, to trace out, in the
Mexican Highlands, the _lower_ and _upper_ boundary line of the
Coniferæ and Oaks. 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, because they announce a climate not yet
invaded, as far as experience has hitherto shown, by that mortal
disease called the black vomit (vomito prieto, a form of the yellow
fever). For the oaks, especially the Quercus Xalapensis (one of the
twenty-two Mexican species of oak which we first described), the lower
line of vegetation, on the way from Vera Cruz to the capital of
Mexico, somewhat below the Venta del Encero, is 3048 feet above the
sea. At the western slope of the plateau, between the South Sea and
Mexico, the inferior line for oaks is something lower; it begins near
a hut named Venta de la Moxonera, between Acapulco and Chilpanzingo,
at the absolute height of 2481 feet. I found a similar difference in
the lower boundary line of the pine-forest. This boundary, towards the
South Sea, in the Alto de los Caxones, north of Quaxinquilapa, is for
the Pinus Montezumæ (Lamb.), which we at first had considered to be
the Pinus occidentalis (Swartz), at the height of 4092 feet; but
towards Vera Cruz, at the Cuesta del Soldado, it rises to 5979 feet.
Both these kinds of tree, therefore, the oaks and firs as specified
above, descended lower towards the Pacific than towards the Caribbean
Gulf. During my ascent of the Cofre di Perote, I found the superior
boundary Line of the oaks to be 10,353 feet; that of the Pinus
Montezumæ 12,936 feet (about 2000 feet higher than the summit of Mount
Ætna) and here, in February, considerable masses of snow had already
fallen.

The greater the heights at which the Mexican cone-bearing trees begin
to show themselves, the more singular is it, in the island of Cuba
(where, at the border of the tropical zone the air, it is true, is
cooled down during northerly winds to 46°.6 Fahr.), to see another
kind of fir (_P. Occidentalis_, Swartz), in the plain itself, or on
the gentle hills of the Isle of Pines, growing among palms and
mahogany trees (_Swietenia_). Columbus even makes mention of a
fir-wood (_Pinal_) in the journal of his first voyage (Diario del 25
de Nov., 1492), at Caya de Moya, north-east of Cuba. At Haiti, too
(St. Domingo), the Pinus occidentalis near Cape Samana descends from
the mountains down to the very beach. The stems of these firs, wafted
by the gulf-stream to the two Azores, Graciosa and Fayal, were among
the principal signs that proclaimed to the great discoverer the
existence of unknown lands in the West.[PB] Is it positively
ascertained that the Pinus occidentalis is entirely absent from
Jamaica, notwithstanding its lofty mountains? We may be permitted to
inquire also, what kind of Pinus grows on the eastern coast of
Guatimala, since the P. tenuifolia (Benth.) is assuredly found only on
the mountains near Chinanta.

On taking a general view of the species of plants which form the upper
tree-boundary in the northern hemisphere from the frigid zone to the
equator; I find, for Lapland, according to Wahlenberg, in the
Sulitelma Mountains (lat. 68°), not acicular-leaved trees but birches
(Betula alba), far above the upper limit of the Pinus sylvestris; and
for the temperate zone I find in the Alps (lat. 45° 45′) Pinus picea
(Du Roi), advanced beyond the birches. In the Pyrenees (lat. 42° 30′),
we find Pinus uncinata (Ram.) and P. sylvestris, var. rubra; within
the tropics in Mexico (lat. 19°–20°), Pinus Montezumæ extends far
beyond Alnus toluccensis, Quercus spicata, and Q. crassipes; and in
the snow-crowned mountains of Quito, beneath the equator, Escallonia
myrtilloides, Aralia avicennifolia, and Drymis Winteri attain the
highest limits. This last species of tree, identical with the Drymis
granatensis (Mut.), and the Wintera aromatica of Murray, presents, as
Dr. Joseph Hooker has shown,[PC] the most singular instance of the
uninterrupted dissemination of the same species of tree from the
southernmost part of Tierra del Fuego and Hermit Island, where it was
discovered as early as 1577 by Drake’s expedition, up to the northern
Highlands of Mexico, over a meridian extent of 86° of latitude or 5160
miles. Where the acicular or needle-leaved trees, as in the Swiss Alps
and the Pyrenees, and not the birch as in the extreme north, form the
boundary of arborescent vegetation on the loftiest mountains, which
they picturesquely encircle, they are immediately followed in their
ascent towards the snow-crowned summits, in Europe and Western Asia by
the Alpine roses, Rhododendra, and at the Silla de Caracas, and the
Peruvian Paramo de Saraguru, by the purplish-red blossoms of the
graceful Befariæ. In Lapland the Rhododendron laponicum immediately
follows the Coniferous trees; in the Swiss Alps, the Rhododendron
ferrugineum and R. hirsutum, and in the Pyrenees the R. ferrugineum
alone; and in the Caucasus the R. caucasicum. But R. caucasicum has
also been found isolated by De Candolle in the Jura mountains (in the
Creux de Vent), 5968 feet lower down, at the inconsiderable height of
from 3303 to 3730 feet. If we would trace out the last zone of
vegetation near the snow line we must name, according to our personal
observation, in tropical Mexico, Cnicus nivalis and Chelone
gentianoides; in the cold mountainous tracts of New Granada, the
woolly Espeletia grandiflora, E. corymbosa, and E. argentea; in the
Andes chain of Quito, Culcitium rufescens, C. ledifolium, and C.
nivale;—yellow-blossomed Compositæ, which replace the somewhat more
northerly lanose herbs of New Granada, and the Epeletiæ, with which
they have so much physiognomical resemblance. This substitution or
repetition of similar and almost identical forms in regions that are
separated from each other by seas or wide intervening tracts, is a
wonderful law of nature. It prevails even in the rarest forms of the
floras. In Robert Brown’s family of the Rafflesiæ, separated from the
Cytineæ, the two Hydnoræ in Southern Africa (H. Africana and H.
Triceps), described by Thunberg and Drege, have, in South America,
their counterpart in the H. Americana of Hooker.

Far above the regions of Alpine herbs, of the grasses and the lichens,
nay, beyond the boundary of perpetual snow, there occasionally appears
a phanerogamic plant, growing sporadically, and as it were isolated,
to the astonishment of botanists; and this occurs both within the
tropics and in the temperate zone, on fragments of rock which remain
free from snow and are probably warmed by open fissures. I have
already mentioned the Saxifraga Boussingaulti, which is found at a
height of 15,773 feet on the Chimborazo; in the Swiss Alps the Silene
acaulis, a clovewort or caryophyllea, has been seen at a height of
11,382 feet. The former vegetates at 640, the latter at 2621 feet
above the respective local limits of snow, heights which were
determined when both the plants were discovered.

In our European Coniferous woods the Red Pine (or Norway Spruce), and
the White (or Silver) Pine show great and remarkable variations as
regards their geographical dispersion on the slopes of mountains.
Whilst in the Swiss Alps the Red Pine (_Pinus picea_, Du Roi, _foliis
compressotetragonis_; unfortunately named by Linnæus and by most
botanists of our time the _Pinus abies_!), forms the limit of tree
vegetation at the mean height of 5883 feet, and only here and there
does the lowly alder (_Alnus viridis_, Dec., _Betula viridis_, Vill.),
advance higher towards the snow-limit; the White Pine (_Pinus abies_,
Du Roi, _Pinus picea_, Linn., foliis planis, pectinato-distichis,
emarginatis), has its limit, according to Wahlenberg, about 1000 feet
lower. The Red Pine does not grow at all in Southern Europe, in Spain,
the Apennines, and Greece; and, as Ramond remarks, it is only seen on
the slope of the northern Pyrenees at great heights, and is entirely
wanting in the Caucasus. The Red Pine extends further to the north in
Scandinavia than the White, which latter tree appears in Greece (on
the Parnassus, the Taygetus, and the Œta), as a variety with long
acicular leaves, _foliis apice integris, breviter mucronatis_, the
Abies Apollinis of the acute observer Link.[PD]

On the Himalaya the acicular-leaved form of trees is distinguished by
the mighty thickness and height of the stem as well as by the length
of the leaf. The chief ornament of the mountain range is the Cedar
Deodwara (_Pinus deodara_, Roxb.), which word is, in Sanscrit,
dêwa-dâru, _i.e._ timber for the gods, its stem being nearly from 13
to 14 feet in diameter. It ascends in Nepaul to more than 11,700 feet
above the level of the sea. More than 2000 years ago the Deodwara
cedar near the River Behut, that is, the Hydaspes, furnished the
timber for the fleet of Nearchus. In the valley of Dudegaon, north of
the copper mines of Dhunpoor in Nepaul, Dr. Hoffmeister, so early lost
to science, found in a forest the Pinus longifolia (Royle), or the
Tschelu Fir, mixed with the lofty stems of a palm—Chamærops martiana
(Wallich).[PE] Such an interspersion of the _pineta_ and _palmeta_ had
already, in the new continent, excited the astonishment of the
companions of Columbus, as a friend and contemporary of the admiral’s,
Petrus Martyr Anghiera, relates.[PF] I myself saw, for the first time,
this blending of pines with palms on the road from Acapulco to
Chilpanzingo. The Himalaya, like the Mexican highlands, besides its
genera of pine and cedar, possesses also forms of the Cypress
(_Cupressus torulosa_, Don.); of the Yew (_Taxus Wallichiana_,
Zuccar.); of the Podocarpus (_Podocarpus nereifolia_, Brown); and the
Juniper (_Juniperus squamata_, Don., and _J. excelsa_, Bieberst.; the
latter species occurring also at Schipke in Thibet, in Asia Minor,
Syria, and the Grecian Islands; on the other hand, Thuja, Taxodium,
Larix, and Araucaria, are forms of the New Continent, which are
wanting in the Himalaya.

Besides the twenty species of pine with which we are acquainted in
Mexico, the United States of North America, in their present extension
to the Pacific, present forty-five described species, whilst all
Europe can only enumerate fifteen. The same difference between
abundance and paucity of forms is shown in the oaks, in favour of the
New Continent (a quarter of the world the most connected and most
elongated in a meridional direction). It has, however, been very
recently demonstrated by the extremely accurate researches of Siebold
and Zuccarini to be an erroneous assertion, that many European species
of pine, in consequence of their wide distribution throughout Northern
Asia, passed over to the Japanese islands, and there mingled with a
genuine Mexican species, the Weymouth pine (_Pinus strobus_, L.), as
Thunberg asserts. What Thunberg considered to be European species of
pine, are species entirely different. Thunberg’s Red Pine (_Pinus
abies_, Linn.) is _P. polita_, Sieb., and often planted near Buddhist
temples; his northern common fir (_Pinus sylvestris_) is P.
Massoniana, Lamb.; his P. cembra, the German and Siberian stone
pine-tree, is P. parviflora, Sieb.; his common larch (_P. larix_) is
the P. leptolepis, Sieb.; his Taxus baccata, the fruit of which the
Japanese courtiers eat as a precautionary measure when attending long
ceremonies,[PG] forms a special genus and is Cephalotaxus drupacea,
Sieb. The Japanese islands, despite the proximity of the Asiatic
Continent, have a very different character of vegetation. Thunberg’s
Japanese Weymouth pine, which would present an important phenomenon,
is moreover a naturalized tree, that differs entirely from the
indigenous pines of the New World. It is Pinus korajensis, Sieb.,
which has migrated from the peninsula of Corea and Kamtschatka to
Nipon.

Of the 114 species now known of the genus Pinus, there is not one in
the whole southern hemisphere, for the Pinus Merkusii, described by
Junghuhn and De Vriese, still belongs to that part of the island of
Sumatra which is north of the equator, that is, to the district of the
Battas. The P. insularis, Endl., belongs to the Philippines, although
at first it was introduced into Loudon’s _Arboretum_ as P.
timoriensis. From our present increasing knowledge of the geography of
plants, we know that there are excluded also from the southern
hemisphere, in addition to the genus Pinus, all the races of
Cupressus, Salisburia (_Ginkgo_), Cunninghamia (_Pinus lanceolata_,
Lamb.), Thuja, one species of which (_Th. gigantea_, Nutt.) at the
Columbia river rises as high as 180 feet, Juniperus, and Taxodium
(Mirbel’s _Schubertia_). I can introduce this last genus here with the
greater certainty, inasmuch as a Cape plant, Sprengel’s Schubertia
capensis, is no Taxodium, but forms a special genus, Widringtonia,
Endl., in quite another division of the Coniferæ.

This absence from the southern hemisphere of the true Abietineæ, of
the Juniperineæ, Cupressineæ, and all the Taxodineæ, as likewise of
the Torreya, of the Salisburia adiantifolia, and of the Cephalotaxus
among the Taxineæ, vividly reminds us of the enigmatical and still
obscure conditions which determined the original distribution of
vegetable forms. This distribution can by no means be satisfactorily
explained either by the similarity or diversity of the soil, by
thermal relations, or by meteorological conditions. I have long since
directed attention to the fact, that the southern hemisphere
possesses, for instance, many plants of the natural family of the
Rosaceæ, but not a single species of the genus Rosa itself. Claude Gay
informs us, that the Rosa Chilensis, described by Meyen, is a variety
that has become wild of the Rosa centifolia, Linn., which has been
naturalized in Europe for thousands of years. Such wild-growing
varieties occupy large tracts in Chili near Valdivia and Osorno.[PH]

In the whole tropical region of the northern hemisphere we only found
one single indigenous rose, our Rosa Montezumæ, and this was on the
Mexican highland, near Moran, at a height of 9336 feet. We may count
among the strange phenomena observed in the distribution of plants,
the total absence of the Agave from Chili, though it possesses Palms,
Pourretias, and many species of Cactus; and although A. americana
flourishes luxuriantly in Roussillon, at Nice, at Botzen, and in
Istria, where it was probably introduced from the New Continent since
the sixteenth century, and where it forms one connected line of
vegetation from the north of Mexico, across the isthmus of Panama, as
far as Southern Peru. With respect to the Calceolarias, I long
believed that, like the roses, they were only to be found exclusively
on the northern side of the equator. In fact, among the twenty-two
species that we brought with us, not one was gathered to the north of
Quito and the volcano of Pichincha; but my friend Professor Kunth
remarks that Calceolaria perfoliata, which Boussingault and Capt. Hall
found near Quito, advances also as far as New Granada, and that this
species, as well as C. integrifolia, was sent by Mutis from Santa Fé
de Bogotá to the great Linnæus.

The species of Pinus, which are so abundant in the wholly
inter-tropical Antilles, as well as in the tropical mountain regions
of Mexico, do not cross the isthmus of Panama, and are wholly wanting
in the equally mountainous parts of tropical South America, that lie
north of the equator; they are equally unknown on the elevated plains
of New Granada, Pasto, and Quito. I have advanced in the plains and on
the mountains from the Rio Sinu, near the isthmus of Panama, as far as
12° south lat.; and in this territorial extent, of nearly 1600 miles
in length, the only forms of needle-leaved trees that I saw, were the
taxoid Podocarpus (P. taxifolia), 64 feet high, in the Andes 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 group of the Coniferæ, the following are common to the
northern and southern hemispheres: Taxus, Gnetum, Ephedra, and
Podocarpus. Long before l’Heritier, the last genus had been very
properly distinguished from Pinus by Columbus on the 25th of November,
1492. He says, “Pinales en la Serrania de Haiti que no llevan piñas,
pero frutos que parecen azeytunos del Axarafe de Sevilla.”[PI] Species
of yew extend from the Cape of Good Hope to 61° north lat. in
Scandinavia, consequently through more than 95 degrees of latitude.
Podocarpus and Ephedra are almost as widely distributed; and even from
among the Cupuliferæ, the species of the oak genus, usually termed by
us a northern form, though they do not cross the equator in South
America, reappear in the southern hemisphere, at Java, in the Indian
archipelago. To this latter hemisphere ten genera of the cone-bearing
trees exclusively appertain, of which we will here cite only the most
important: Araucaria, Dammara (_Agathis_, Sal.), Frenela (comprising
about 18 Australian species), Dacrydium and Lybocedrus, whose habitat
is both in New Zealand and the Straits of Magellan. New Zealand
possesses one species of the genus Dammara (_D. australis_), but no
Araucaria. The contrary, by a singular contrast, is the case in New
Holland.

In the form of acicular-leaved trees, Nature presents us with the
greatest length of stem existing in arborescent productions. I use the
term arborescent, for, as we have already remarked, among the
Laminariæ (the oceanic algæ) Macrocystis pyrifera, between the coast
of California and 68° south lat., often attains a length of more than
400 feet. If we exclude the six Araucarias of Brazil, Chili, New
Holland, the Norfolk Islands and New Caledonia, then those Coniferæ
are the highest, whose habitat is the temperate zone of the North. As
we have found among the family of the palms the most gigantic of all,
the Ceroxylon andicola, about 192 feet high, in the temperate Alpine
climate of the Andes, so in like manner do the loftiest cone-bearing
trees belong, in the _northern_ hemisphere, to the temperate
north-western coast of America and to the Rocky Mountains (lat. from
40° to 52°), in the _southern_ hemisphere to New Zealand, Tasmania or
Van Dieman’s Land, to Southern Chili and Patagonia, (where the lat. is
again from 43° to 50°). The most gigantic forms among the genus Pinus
are Sequoia (Endl.), Araucaria, and Dacrydium. I only name those
species whose height not merely reaches but often exceeds 200 feet.
That the reader may have a standard of comparison, he is reminded that
in Europe the loftiest Red and White Pines, especially the latter,
reach a height of from 160 to 170 feet; for instance, in Silesia, the
pine in the Lampersdorf forest, near Frankenstein, long famous for its
altitude, is only 158 feet high, although 17 feet in girth.[PJ]

We give the following examples:—

Pinus Grandis (Dougl.), in New California, attains a height of 202–224
feet.

Pinus Frémontiana (Endl.), also there, and probably of the same
height.[PK]

Dacrydium Cupressinum (Solander), in New Zealand, above 213 feet.

Pinus Lambertiana (Dougl.), in North-western America, 223–234 feet.

Araucaria Excelsa (R. Brown), the Cupressus columnaris of Forster, in
Norfolk Island and the surrounding rocks, 182–223 feet. The six
Araucariæ hitherto known fall into two groups, according to Endlicher:

α. The American (Brazil and Chili), A. brasiliensis [Rich.], between
15° and 25° south lat., and A. imbricata [Pavon], between 35° and 50°
south lat.; the latter 234–260 feet;

β. The Australian (A. Bidwilli [Hook.] and A. Cunninghami [Ait.] on
the eastern side of New Holland, A. excelsa of Norfolk Island, and A.
Cookii [R. Brown] of New Caledonia). Corda, Presl, Göppert, and
Endlicher have already found five fossil Araucariæ in lias, in chalk,
and in lignite.[PL]

Pinus Douglasii (Sab.) in the valleys of the Rocky Mountains and at
the Columbia River (north lat. 43°–52°). That meritorious Scotch
botanist, whose name this tree bears, suffered a dreadful death in
1833, when he came from New California to collect plants on the
Sandwich Islands. He inadvertently fell into a pit, into which one of
the wild bulls of that country, always viciously disposed, had
previously fallen. This traveller has described from accurate
measurements a stem of P. Douglasii, which at three feet from the
ground was 57½ feet round, and 245 feet high.[PM]

Pinus Trigona (Rafinesque), on the western slope of the Rocky
Mountains.[PN] This “gigantic fir” was measured with great care; the
girth of the stem at 6¼ feet above the ground was often from 38 to 45
feet. One stem was 300 feet high, and without branches for the first
192 feet.

Pinus Strobus (in the eastern part of the United States of North
America, especially on this side of the Mississippi, but also again in
the Rocky Mountains, from the source of the Columbia to Mount Hood,
from 43° to 54° north lat.), in Europe called the Weymouth Pine, and
in North America the White Pine, commonly no more than 160 to 190 feet
high, but several have been seen in New Hampshire of 250 and 266
feet.[PO]

Sequoia Gigantea (Endl.; the Condylocarpus, Sal.), of New California,
like the Pinus trigona, about 300 feet high.

The nature of the soil and the conditions of heat and moisture, on
which the nourishment of plants simultaneously depends, promote, it
must be admitted, the development and the increase of the number of
the individuals in a species; but the gigantic height attained by the
stems of a few among the many nearly allied species of the same genus
is not dependent on soil and climate but on a specific organization,
on internal natural disposition, common alike to the vegetable and to
the animal world. With the Araucaria imbricata of Chili, the Pinus
Douglasii of the Columbia River, and the Sequoia gigantea of New
California (245–300 feet) contrasts most strongly—not the Willow
(_Salix arctica_) stunted by cold or mountain height, and only two
inches high,—but a little phanerogamic plant in the beautiful climate
of the southern tropical region, in the Brazilian province of Goyaz.
The moss-like Tristicha hypnoides, of the Monocotyledonous family of
the Podostemeæ, hardly attains the height of three lines. “While
crossing the Rio Clairo in the province of Goyaz,” says an excellent
observer, “I perceived on a stone a plant, the stalk of which was not
more than three lines high, and which I considered at first to be a
moss. It was, however, a phanerogamic plant, supplied with sexual
organs like our oaks, and those gigantic trees which raised their
majestic heads around.”[PP]

Besides the height of the stem, the length, breadth, and position also
of the leaves and fruit, the aspiring or horizontal, almost umbellate
ramification, the gradation of the colour from fresh or silver-greyish
green to dark brown, give a peculiar physiognomical character to the
Coniferæ. The acicular leaves of Pinus Lambertiana (Douglas) in
North-Western America are five, those of the P. excelsa (Wallich) on
the southern slope of the Himalaya near Katmandu, seven, and those of
P. longifolia (Roxb.) on the mountain range of Cashmere, more than
twelve inches long. Moreover, in one and the very same species, these
acicular leaves vary in the most remarkable manner, from the combined
influence of the nourishment derived from soil and air, and of the
height above the level of the sea. I found these variations in the
length of the leaves of our common wild pine (_Pinus sylvestris_) so
great, while travelling in a west and east direction over an extent of
80° of longitude (more than 3040 miles) from the Scheldt, through
Europe and Northern Asia, to Bogoslowsk, in the Northern Ural, and
Barnaul beyond the Obi, that occasionally, deceived by the shortness
and rigidity of the leaves, I have mistaken it for another species of
pine, allied to the mountain fir, _P. rotundata_, Link, (_Pinus
uncinata_, Ram.) These are, as Link correctly observes,[PQ]
transitions to Ledebour’s P. sibirica of the Altai.

The delicate and pleasing green though deciduous foliage of the
Ahuahuete (_Taxodium distichum_, Rich., _Cupressus disticha_, Linn.)
on the Mexican plateau especially delighted me. In this tropical
region the tree, swelling out to a portly bulk, and the Aztec name of
which signifies “water-drum” (from atl, water, and huehuetl, drum),
flourishes from 5750 to 7670 above the level of the sea, whilst it
descends towards the plain in the marshy district (Cypress swamps) of
Louisiana as far as 43° lat. In the southern States of North America
the Taxodium distichum (_Cyprès chauve_), as well as in the lofty
plains of Mexico, attains a height of 128 feet, with an enormous
girth, the diameter being from 30 to nearly 40 feet, when measured
near the ground.[PR] The roots, too, present a very remarkable
phenomenon, for they have woody excrescences, which are sometimes of a
conical and rounded, sometimes of a tabular shape, and project three
and even nearly five feet above the ground. Travellers have compared
these woody excrescences, in spots where they are numerous and
frequent, to the grave-tablets of a Jewish churchyard. Auguste de St.
Hilaire remarks, with much acuteness: “These excrescences of the bald
cypress, which resemble boundary-posts, may be regarded as exostoses,
and like these live in the air; adventitious buds would doubtless
escape from them, if the nature of the tissue of the coniferous plants
did not oppose itself to the development of those concealed germs that
give birth to these kinds of buds.”[PS] In addition to the above, a
remarkably enduring vitality is manifested in the roots of
cone-bearing trees by the phenomenon which, under the name of
“Effervescence,” (aftergrowth?) has attracted, in many ways, the
attention of botanical physiologists, and which phenomenon, it
appears, rarely displays itself in other dicotyledonous plants. The
stumps of the felled white Pine, left in the ground, form, during a
succession of several years, new layers of wood, and continue to
increase in thickness, without throwing out shoots, branches, or
leaves. The excellent observer Göppert believes, that this takes place
solely through nourishment derived from the roots, which the extremity
of the stem receives from a neighbouring living tree of the same
species. The roots of the living tree he conceives are organically
incorporated with those of the stump.[PT] Kunth, in his excellent new
_Lehrbuch der Botanik_, is opposed to this explanation of a
phenomenon, which was even known, though imperfectly, to
Theophrastus.[PU] According to him, this process is perfectly
analogous to that by which metallic plates, nails, carved letters,
nay, even stags’ horns become imbedded within the body of wood. “The
cambium, that is, the thin, walled cellular tissue, conducting
muco-granular sap, from which new formations alone proceed, continues
without any relation to the buds (being perfectly independent of them)
to deposit new layers of wood on the outermost layer.”[PV]

The relation above alluded to, between the absolute height of the
ground and the geographical as well as isothermal latitude, shows
itself often, no doubt, when one compares the arborescent vegetation
of the tropical part of the Andes chain with the vegetation of the
north-west coast of America, or the banks of the Canadian lakes. The
same remark was made by Darwin and Claude Gay in the southern
hemisphere, when they, in their descent from the plateau of Chili,
advanced towards Eastern Patagonia, and the Archipelago of Tierra del
Fuego; here woods of Drymis Winteri, together with Fagus antarctica
and Fagus Forsteri, cover every thing with long uniform rows in a
northern and southern direction down to the low lands. Trifling
deviations from the law of constant _station-ratios_ between _mountain
height_ and _geographical latitude_, depending or local causes, not
sufficiently investigated, occur even in Europe. I would call to mind
the limits of altitude for the birch and common fir in a part of the
Swiss Alps, on the Grimsel. The fir (_Pinus sylvestris_) flourishes
there up to 6330; and the birch (_Betula alba_) up to 6906 feet;
beyond them again there is a belt of stone pines (_Pinus cembra_),
whose upper boundary is 7343 feet. The birch, in consequence, lies
there between two belts of Coniferæ. According to the excellent
observations of Leopold von Buch, and the more recent ones of Martius,
who also visited Spitzbergen, the limits of the geographical
distribution in the high Scandinavian north (in Lapland) are as
follows: “The Fir extends to 70°; the White Birch (_Betula alba_) to
70° 40′; the Dwarf-Birch (_B. nana_) to 71° at least: Pinus cembra is
entirely wanting in Lapland.”[PW]

As the length and the position of the acicular leaves define the
physiognomic character of the coniferæ, this is still more designated
by the specific difference of the leaf-breadth, and the parenchymatous
development of the appendicular organs. Several species of Ephedra may
be said to be almost leafless; but in Taxus, Araucaria, Dammara,
(Agathis), and the Salisburia adiantifolia of Smith (_Gingko biloba_,
Linn.), the breadth of the leaf gradually increases. I have here
arranged the genera morphologically. Even the names of the species, as
first chosen by botanists, indicate such an arrangement. Dammara
orientalis of Borneo and Java, often 11 feet in diameter, was at first
named loranthifolia: Dammara australis (Lamb.), in New Zealand, rising
to 150 feet high, was originally named zamæfolia. Neither of these has
acicular leaves, but “folia alterna oblongo lanceolata, opposita, in
arbore adultiori sæpe alterna, enervia, striata.” The lower surface of
the leaf is densely covered with stomata. These transitions of the
appendicular system, from the greatest contraction to a broad leaf
surface, possess, like every advance from simple to compound, both a
morphological and a physiognomical interest.[PX] The short-stalked,
broad, split leaf of the Salisburia (Kämpfer’s Ginkgo), has also the
breathing pores (stomata) only on the inferior side. The original
habitat of the tree is not known. It became distributed from the
Chinese temples to the gardens of Japan, in consequence of the
intercourse that existed in olden times between the congregations of
Buddha.

I was a witness of the singularly painful impression, which the first
sight of a pine-forest at Chilpanzingo made on one of our companions
in travelling from a port in the South Sea through Mexico to Europe.
Born in Quito, under the equator, he had never seen needle-leaved
trees and folia acerosa. The trees appeared to him to be leafless, and
because we were journeying towards the cold north, he thought he
recognised already, in the extreme contraction of the organs, the
impoverishing influence of the Pole. The traveller, whose impressions
I am here describing, and whose name neither Bonpland nor myself can
mention without regret, was an excellent young man, the son of the
Marquis de Selvalegre, Don Carlos Montufar, whose noble and ardent
love of freedom courageously led him, a few years later, to a violent,
though not dishonourable, death, in the war of independence, waged by
the Spanish colonies.

Footnote 94:

p. 227—“_Pothos plants, Aroideæ_.”

Caladium and Pothos are forms appertaining exclusively to the tropical
world, whilst the different species of Arum belong more to the
temperate zone. Arum italicum, A. dracunculus, and A. tenuifolium
advance as far as Istria and Friuli. No Pothos has hitherto been
discovered in Africa. The East Indies possess several species of this
genus (P. scandens and P. pinnata), which have a less beautiful
physiognomy and are of less luxuriant growth than the American Pothos
plants. We discovered a beautiful true arborescent Aroidea (Caladium
arboreum), having a stem from 16 to more than 21 feet in height, near
the convent of Caripe, east of Cumana. Beauvois found a singular
Caladium (Culcasia scandens) in the kingdom of Benin.[PY] In the
Pothos form the parenchyma occasionally expands to so great a degree
that the leaf-surface becomes perforated with holes, as in Calla
pertusa (Kunth), and Dracontium pertusum (Jacquin), which we collected
in the forests of Cumana. It was the Aroideas which first drew
attention to the remarkable phenomenon of the _fever-heat_ evolved by
certain plants during the period of their inflorescence, and which
even sensibly affects the thermometer, and is connected with a great
and temporary increase in the absorption of oxygen from the
atmosphere. Lamarck, in 1789, observed this increase of temperature in
the Arum italicum. According to Hubert and Bory de St. Vincent, the
vital heat of the Arum cordifolium rises in the Isle of France to 110°
or 120°, whilst the temperature of the surrounding air is only 66°.2
Fahr. Even in Europe, Becquerel and Breschet found a difference of
39°.4. Dutrochet observed a paroxysm,—a rhythmical decrease and
increase of vital heat,—which appeared by day to attain a double
maximum. Théodore de Saussure remarked analogous augmentations of
heat, although only of 1°.1 and 1°.8 Fahr., in other families of
plants; as, for instance, in Bignonia radicans and Cucurbita pepo. In
the latter, the male plant exhibited a greater increase of temperature
than the female, when measured by a very sensitive thermoscopic
apparatus. Dutrochet—whose early death is greatly to be regretted, on
account of the important services he rendered to physics and vegetable
physiology—likewise observed,[PZ] by means of thermo-magnetic
multiplicators, a vital heat of 0°.25 to 0°.67 Fahr. in many young
plants (Euphorbia lathyris, Lilium candidum, Papaver somniferum), and
even among funguses, in many species of Agaricus and Lycoperdon. This
vital heat disappeared at night, but not by day, even when the plants
were placed in the dark.