ridges of the mountain chains, which may be regarded as the margins of the basin, and cannot be traced with accuracy. From east to west it extends from the Atlantic to the Cordilleras, on the north it has a sinuous outline on the summits of the Sierra de Araray and the Parimé chain to the bay of Guayaquil; and on the south between the provinces of Minas Geraes and San Paulo, bending to the head waters of the Paraguay onward to the Andes in Bolivia.

PHYSICAL CHARACTERS.-From the Andes, plains of almost boundless extent gradually incline towards the Atlantic. Several ranges of low mountains intersect them, but their comparative importance is trifling, and their elevation rarely exceeds 4,000, never 6,000 feet; which is insufficient to produce any material change in the vegetation, though permitting some plants to adopt a selection. Balbi regards these plains as table lands, with an elevation from 1,030 to 1,660 feet. Granite and syenite form the bases of both the mountain chains and the lowlands, on which repose gneiss, mica slate, chlorite slate, quartz rock, and limestone. On these again are sandstone and slate clay, with alluvial deposits. True volcanic rocks have no existence. The soil varies; in the forest it is either a rich dark vegetable mould, or a fruitful deep red loam, and both are astonishingly productive under cultivation. In the more open country sand enters largely into the soil, and when opposed to a moist as well as warm atmosphere, displays a varied vegetation. The soil in the neighbourhood of the rivers has, from their periodical inundations, attained the greatest fertility, and gives birth to an excess of luxuriance.

CLIMATE.-The equator traverses the region, but the climate partakes of that unsteady character with regard to humidity which is so frequent, and at the same time so

productive of variety. Para will give us the state of the climate on the plains nearest the river. The atmosphere is hot and sultry, and the range of temperature throughout the year very small; the mean is 84°, and the annual fall of rain from 80 to 100 inches. More to the south, the year is regularly distributed into the wet and dry seasons. At Rio Janeiro the rains occur from September to March, the temperature high, and often with much electrical disturbance of the atmosphere. In the interior of the country rain is less abundant, and in some places scarce. The seasons are the reverse of those in the neighbouring Oronoco regions.

FLORA. In this region the American tropical families are in excess, and have the greatest number of representatives. The vegetation has a twofold character, comprising the forest, which extends in a broad belt along the coast from north to south, and the Sertam country, a contraction of dezertam, where grasses and shrubs prevail, and occasionally a few trees in sheltered valleys or ravines.

The forest is composed of an endless number of trees, of which to mention some would be placing others too much in the background. These trees attain a great height, with straight clear stems, their foliage uniting in a canopy above, and leaving all beneath in perfect shade and quiet. This great longitudinal developement is not favourable to a protracted existence, as age and climate soon attack the trees, and their places are left vacant for others. Of the natural families which abound in greatest intensity, and are also conspicuous for their interest, are, palmæ, assuming much variety of habit, cinchonaceæ, melastomaceæ, piperaceæ, myrtaceæ, marcgraaviaceæ, gesnerieæ, sapindaceæ, vochyaceæ, guttiferæ, malpighiaceæ, hippocrateacea, and bromeliacea. Epiphytic plants festoon the trees in multitudes, but here orchi

daceæ are not frequent, and their place is supplied by species of bromelia, tillandsia, the strange pothos, and many ferns. The twining plants are freely supplied by passifloreæ, leguminosa, convolvulaceæ, aristolochiæ, asclepiadeæ, and mikania.

The Sertam country has its own vegetable charms, and though much occupied by grasses with a dull grey hairy surface, has large spaces covered with bushwood, and sometimes even trees. Many of these are attractive, and chiefly belong to cinchonacea, compositæ, apocyneæ, malpighiaceæ, and euphorbiacea. A few of the more numerous genera are declieuxia, rhexia, banisteria, gaudichaudia, croton, wedelia, kleinia, and sauvagesia. The trees are described by Von Martius as attaining only fifteen or twenty feet in height, and growing as a light open grove. The chief are derived from laplacia, gomphia, marcgraafia, vochysia, qualia, solanum, byrsonima, erythroxylon, panax, and rhexia; and amaryllideæ are frequent.

Some peculiarities may be noticed on the sides and summits of the different mountain chains. On Itacolumi, or the Child of Stone, a mountain near Villa Rica, attaining 5,710, Von Martius saw the curious arborescent lilies of barbacennia bicolor, b. tricolor, b. tomentosa, b. luzulæfolia, b. ensifolia, vellosia abietina, and v. taxifolia. Other characterizing genera are galium, morinda, declieuxia, oxypetalum, ditassa, lisianthus, exagum, phyllanthus, lavradia, gloxinia, gesneria, vitis, and ternstroemia. Growing on the ironstone floetz formation, and supposed to be distinctive of it, were, laurus erythropus, bauhinia ferruginosa, abatia tomentosa, brysonima nitidissima, banisteria versicolor, vanillosma firmum, lisianthus pulcherrimus, phyllanthus robustus, and mikania glauca. The swampy ground is distinguished by species

of hydrocotyle, drosera, andromeda, gaultheria, utricularia, sauvagesia, and eriocaulon.

RELATIONS.-Among the alpine plants, if so they can be called, are many intimately connected with the vegetation of the temperate regions of Europe and North America, as panax, clethra, vitis, galium, and gaultheria. Ambrosia artemesiæ folia, a strand plant of the Iroquois Region, occurs on the shores of Paraiba. Walsh saw patches of the European fern, aspidium filix mas, and also bushes of Rubus occidentalis. The same traveller mentions avena sterilis attaining a height of ten feet. For some time the existence of canna indica was supposed to confer an interesting point of identity with India, but it is now known to be a frequent plant within the tropics.

XIV.—THE PARAGUAY REGION.

EXTENT.-It embraces the space of country traversed by the Paraguay River and its tributary streams; its outline will thus extend from the coast between the Brazilian provinces of San Paulo and Minas Garaes, and, arching to the north, terminate on the limits of the Pampas Region, and again on the south along the course of the Rio Plata, and the hitherto unascertained margin of the same region.

PHYSICAL CHARACTERS.-A portion of this country is not so completely a plain as would appear from the maps, as towards the Andes several spurs are sent off which spread into the interior. San Paulo is sufficiently elevated to affect considerably its productions, and the difference between it and Minas Geraes has struck several travellers. Generally the soil is rich and fertile,

but there are large spaces covered with scarcely anything but sand, and yielding a poor bushy vegetation.

CLIMATE. That of San Paulo corresponds to the whole region; the mean temperature of the year is 73°, and the range is small. Hoar frost is sometimes seen, but snow is unknown. The rains occur at two periods, the autumnal being the heaviest.

FLORA. The tropical features, which the Amazon Region possesses in such intensity, have greatly diminished; palmæ are few; ferns continue very numerous, but with a habit more suited to a drier climate. Baccharis and other compositæ cover the sandy districts, and cacteæ are frequent. Umbelliferæ, though far from numerous, have a greater preponderance than in neighbouring regions. The forest is open, and composed of fine trees; arborescent ferns still continue, and where they assemble in groves exclude all other vegetation, a peculiarity possessed by them when growing gregariously. In a collection of plants made in the warmer portion of the region, composita were a 12th, leguminosa a 15th, cinchonacea and orchidea a 20th, melastomaceæ a 29th, labiatæ and solaneæ a 40th.

Tristan da Cunha, situated in 37° S. lat., is known to possess 113 indigenous plants, among which are several umbelliferæ, which induces us to regard the island as a fragment of this region.

RELATIONS. These are perhaps feeble with distant regions, whilst they are not strong with those in the vicinity. Araucaria brasiliensis is frequent in the forest, a representative of an Australian genus, though having a nearly allied species in Chili.

VOL. II.

BB