FLORA.-Only a partial examination has been made, and our chief acquaintance with the vegetation is due to M. Defontaines. It is owing to this that a very powerful connexion has been traced with the vegetable productions on the northern shores of the Mediterranean. When our knowledge of the interior is more complete, a greater proportion of peculiar forms will undoubtedly be discovered; at least such is a fair inference from what is observed elsewhere. Upwards of 2,000 species are known, and it has been remarked that, though a great number are peculiar, they belong to genera shared with Europe. In 344 woody kinds, about a hundred are peculiar. Those groups of plants which prefer a dry warm atmosphere, such as leguminosæ, malvaceæ, labiatæ, solaneæ, caryophylleæ, and certain compositæ, prevail. Among characterising genera may be mentioned rhus, zizyphus, vitex, viburnum, diospyros, pistacia, celtis, tamarix, juniperus, thuja, olea, adonis, verbascum, smilax, cercis, cistus, nerium, and agave. Pinus halepensis grows in large forests, and other species are frequent; a large surface is occupied by phoenix dactylifera. On the Atlas range are many quercus, and fagus, alnus, salix, with many herbaceous genera common to Europe.

RELATIONS.-We separate this from the Nile region, on account of its alpine vegetation; and from the European regions, though undoubtedly some affinities are great, since the same combination of alpine and lowland vegetation does not occur in any of them. The alpine features more closely coincide with the Pyrenees, whilst those of the plains recall Italy and the south-east of Europe.

XXXI. THE NILE REGION.

EXTENT.-The whole portion of country traversed by the Nile and its tributary branches. Towards its source the elevation of the surface compensates for the lower latitude, producing a milder climate and corresponding vegetation. It thus embraces a broad belt of country between the Red Sea and the Great Sahara, by which its isolation from other botanical regions is rendered nearly complete.

PHYSICAL CHARACTERS.-There is much diversity in the surface. The valley of Lower Egypt presents an uniform plain, almost without a hill, and subject to the periodical inundations of the Nile. Gradually a chain of bare and rugged mountains converge towards the river, leaving the intervening valley with only the breadth of a few miles. Upper Egypt assumes a bolder character; the banks of the Nile become rocky, and the inundations far less general. In Nubia, for this reason, the river is sometimes unapproachable, and a laboured irrigation is practised. Abyssinia is traversed by piles of mountain masses of extreme barrenness, and with intervening valleys, whose rich and productive soil is some compensation for their sterility. There is here a general elevation of the surface, and some of the mountains attain a great height. Egypt has been justly considered a granary with almost an unfailing supply; a productiveness which is dependent more on the overflowings of the Nile, than on any inherent richness of its somewhat sandy soil.

CLIMATE. Few regions would, perhaps, supply us with more interesting sources of the adaptation of the vegetation to the climate, if we were furnished with the necessary information. The temperature is warm; that of Lower Egypt particularly so, the mean summer heat of Cairo

being 92°. Rain is scarce; the dews, however, are heavy. Rain is more frequent about the Delta, and in the vicinity of the coast, than elsewhere. Thunder and lightning are even more uncommon than rain. The seasons are not very strongly marked, and run imperceptibly and rapidly into each other. Summer commences in June, and lasts till September. Autumn succeeds. The cold season begins in December, and lasts two months; and in February spring makes its appearance. Harvest succeeds in seven or eight weeks to the sowing; and the trees lose their leaves in the cold seasons, and are rapidly replaced by new. The inundations of the Nile, to which Egypt owes its vast fertility, are due to the autumnal rains of Abyssinia. Their effects are visible in the first week of July, when the river begins to swell; and, continuing to increase, has reached half its augmentation in August, and its greatest in the latter days of September. For two weeks it continues stationary, till on the 10th of November it has fallen one-half, and afterwards continues to decrease till the 16th of May, when it has reached its lowest.

FLORA. For three months the vegetation of Egypt is bathed in the overflowing waters of the Nile. As these subside a rapid vegetation ensues, the period of fructification is hastened and has passed away, and during the remainder of the year a parching aridity prevails. The superior luxuriance belonging to the former would be greatly misplaced in the latter; and, regarding the character of the vegetation, that particular variety has been dispensed to it which is congenial to the dry seasons, and will survive the inundation. It is not be expected that the flora will be numerous; and the aspect of the country is uniform and tame, being only relieved by some accidental trees of mimosa, zizyphus, phoenix dactylifera, and cucifera thebaica. Abyssinia is more fruitful, and contains many

spots of rich variety, and patches of fine forest. In accordance with these views, succulent plants are common; the leaves are those suited to a dry atmosphere, and spinous organs are much developed. It has been deemed singular that fungi should be entirely wanting in a soil for a certain period saturated with moisture, and apparently suited to their ephemeral existence. In some barren spots, beyond the reach of the inundation, certain plants have established themselves, and drag on a starved and stunted existence. The valley of Lower Egypt is not likely to present a very perfect specimen of an indigenous flora, having been under the closest cultivation for many ages; and it is probable that its alluvial soil has been the gradual deposit of the Nile, and that it has received its vegetation from Abyssinia and elsewhere. We shall, therefore, direct our attention chiefly to the former.

Some insight into the flora of Abyssinia has been obtained, particularly by Salt and Caillaud, who made collections. Many of its species are found to be peculiar, and to bear a larger proportion to the entire vegetation. Leguminosæ are very abundant through acacia, cassia, mimosa, pterolobium, erythrina, alhagi, desmanthus, and bauhinia. Other conspicuous genera are euphorbia, avicennia, juniperus, tamarix, zygophyllum, fagonia, polymnia, œerua, brucea, balsamodendron, cordia, and pistacia. Coffea arabica is indigenous, and fresnella fontanesii forms thick groves on some of the hills. Gramineæ are numerous, and several kinds of holcus, sorghum, poa, and andropogon, are cultivated. In those frequent situations, where neutral salts are mixed with the soil, are salsola, salicornia, traganum, and calligonum. The bed of the Nile is often closely set with sedges and flags. Papyrus antiquorum is equally found here and in the lakes of Abyssinia. Nelumbium speciosum has disappeared; yet still

the rivers of India and China are enlivened by its fine red flowers. The white-flowered nymphæa lotus abounds; and n. cærulea is sometimes seen. Arum colocasia is cultivated for food.

The vast sea of land of the Great Sahara is an effectual barrier to the extension of the flora of this region, in the direction over which it prevails. It consists of a low flat plain, with the surface covered with white and grey quartz, and becoming more shingly towards the east, or in the direction of the prevailing wind. It is towards its eastern part that the oases chiefly exist, affording a grateful resting-place to the traveller, occupied by a rather numerous population, and having a lively vegetation. The dreariness of the surrounding waste is here replaced by groves of date-palm. Acacia vera and other species shade the gushing streams, and tufts of grasses vary the surface.

RELATIONS. Many of the plants frequent on the shores of the Mediterranean appear in Lower Egypt; and some of those of Arabia cross the Red Sea to Nubia and Abyssinia. The most interesting relation, however, is with the South Africa Region through several species of mesembryanthemum, pelargonium abyssinicum, protea abyssinica, hagenia abyssinica, brunia ciliata, albuca abyssinica, and geissorhiza abyssinica. Adansonia digitata of the west coast re-appears, and the trunk is applied to entombing the dead. A tropical character is displayed in some of the genera enumerated, and in musa ensete. Rosa abyssinica occurs in the valleys of that country.

XXXII. THE ASIA MINOR REGION.

EXTENT.-Let us suppose ourselves stationed at the head of the Persian Gulf, and then project lines to the