smaller genus blæria; Diosmea prevail extensively in diosma, agathosma, adenandra, and baryosma; Asclepiadea, the numerous and strange stapelia, with huernia and gomphocarpus; Crassulaceæ, a family with some kindred habits, is represented in crassula, rochea, leptas, and cotyledon; Ficoidea, by the various mesembryanthemum, with tetragonia and hymenogyne; Polygaleæ, in polygala, muraltia, and mundia; Composite prevail extensively, and many are characterized by that peculiar texture of the flower belonging to everlastings. Most of the following genera are peculiar: chrysocoma, arctotis, othonna, osteospermum, tarchonanthus, sphnegyne, erichrysum, cacalia, pteronia, berckleya, and gazania; Orchidaceae cannot be supposed to be abundant; disa and satyrium find convenient localities on the Table Mountain, and some of them are scarce; Iridea abound in ixia, gladiolus, tritonia, watsonia, hesperantha, sparaxis, babiana, and trichonema; Amaryllide equally so in hæmanthus, strumaria, brunsvigia, nerine, cyrtanthus, and gethyllis. There are yet several important genera requiring notice: euphorbia has a group of species which simulate the habit of cacteæ, and supply their place; aloe has a great variety of species, and others are frequent, in oxalis, phyllica, restio, struthiola, cliffortia, roella, hypoxis, eucomis, massonia, lachenalia, and streletzia. Heliophila, a cruciferous genus, is monomic. Lobelia, cestrum, lyceum, chironia, and others prevail. Two families also claim to be regarded as monomic,—bruniaceæ and penæaceæ. Climbing plants are uncommon, as are also cryptogamic. Some ferns are found on the sides of the Table Mountain, the particular flora of which has other evidences of a moister atmosphere. The mass of the vegetation is to a great extent confined to the colony, and several of its more peculiar groups, ericaceæ, proteaceæ, diosmeæ, and restiaceæ, do not appear on the arid karroo,

which is occupied by gregarious species of lyceum, acacia, euphorbia, and mesembryanthemum. Some have a very limited range, and the species of stapelia abound more particularly on the arid sands of the west coast.

RELATIONS. The various relations of a region so complete as that of South Africa must be extremely interesting; and it seems probable that so rich a vegetation, with a liberal hand, gives more representatives to other regions than it receives from them. Passing over a more extensive view of its relations, we will confine our notice to groups having their chief existence elsewhere. A few of the genera of Europe, North America, and Siberia, have species here; the presence also of salix, bryonia, and viola, recalls a different latitude and climate. In common with the northeastern portion of Africa, it has acacia vera, cucumis colocynthis, and a zizyphus; and has an affinity with New Holland in metrosideros angustifolia. Several introduced plants are becoming diffused, as solanum nigrum, sonchus oleraceus, and polygonum persicaria.

XXVI. THE MOZAMBIQUE REGION.

EXTENT. That portion of the east coast of Africa between 10° N. lat. and the south tropic in 23° 28′ has been so little visited, that nothing is known of its vegetation, except that it is clothed with rich forests, and has a climate in all respects tropical.

PHYSICAL CHARACTERS.-Spacious plains abound near the coast, traversed by considerable rivers, and liable to partial submersion.

CLIMATE.-Tropical, moist, and frequently unhealthy, but well suited to the growth of the nutmeg, cinnamon,

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and similar productions of a tropical climate in its

excess.

FLORA. Further than that it abounds in luxuriant forest, and supplies us with Columba-root and a few other articles of commerce, little is known concerning it, and the native rulers are too jealous of foreigners to permit any examination of the interior of the country.

RELATIONS.-It differs so entirely from the regions to the north and south, that the propriety of its separation from them seems undoubted.

XXVII. THE MADAGASCAR REGION.

EXTENT. The large and fruitful island of Madagascar, situated between 12° and 26° S. lat., and the far smaller islands of Bourbon, Mauritius, and the Séchelles.

PHYSICAL CHARACTERS.-In Madagascar, extensive fertile plains extend from the shores towards a lofty range of mountains in the interior. The soil is represented as rich and highly productive, and extensive marshy districts are occupied as rice-fields.

CLIMATE.-Tropical, moist, and in some parts of Madagascar extremely fatal to human beings.

FLORA.-Just enough of the productions of Madagascar are known to assure us they are peculiar, and to stimulate research. The vegetation is luxuriant, and varied with the usual aspect of the tropics. The natural family of chlenaceæ is confined to it; areanthes and other orchidacea abound. Tanghinia veneniflua, yielding a most energetic poison, and hydrogeton fenestralis, remarkable for the structure of its leaves, are both natives. Several species of the small family of homalineæ are found in the islands, and also the myrtaceous genus jossinia.

The Mauritius has rather an extensive and tolerably well-known flora, and with a fair proportion of peculiar species. Danais and chasalia are confined to it.

Bourbon closely resembles the Mauritius.

The Séchelles are chiefly remarkable for a doublefruited variety of cocos nucifera, which is produced on three of the islands.

RELATIONS. From its position, Madagascar would seem to belong to Africa, but such observations as have been instituted on its flora and that of the neighbouring coast, point out decidedly stronger affinities with India. Edwardsia is common both to New Zealand and the Mauritius.

XXVIII. THE WEST AFRICA REGION.

EXTENT.-A considerable tract of country, inhabited by many populous nations, situated between the Great Sahara or central desert of Africa and the Atlantic Ocean, and Cape Blanco, in 20° 55, N. lat., and 23o 28, S. lat., or the south tropic.

PHYSICAL CHARACTERS.-In the neighbourhood of the coast the surface is composed chiefly of level plains, broken occasionally by ranges of low hills, and with chains of lofty mountains in the background, of primitive formation. Much of the soil is alluvial, and surprisingly productive; and the banks of the numerous rivers are low, and during a part of the year extensively overflowed by the rising of the waters. At the mouth of some of the rivers are large salt-water marshes, covered by mangrove and other congenial plants. But salt, so abundant in other parts of Africa, is here in the interior so scarce as to be greatly prized.

CLIMATE.-Tropical, and generally moist; but in the vicinity of the desert partaking of its aridity.

FLORA.-Over this extensive surface there is little variety in the vegetation; the same forms are continually repeated, and there is a scarcity of some of those elsewhere so abundant in the tropics. Palmæ have few species; elais guineensis, phoenix spinosa, raphia vinifera, and the cocoa-nut, are the chief. Musacea, scitamineæ, piperaceæ, are scarce. Yet there is a denseness and luxuriance in the vegetation hardly surpassed in any other part of the world. The forest is extensive and magnificent, the trees attaining a large size; and on the banks of the rivers which have been navigated some have been seen of enormous dimensions. Cinchonaceæ, leguminosa, and malvaceæ abound; ficus, cassia, acacia, and euphorbia have many species. Some of the more conspicuous belong to bombax, adansonia, sterculia, cadaba, parkia, hoflandia, melhania, pentadesma, cratæva, capparis, grewia, pterocarpus, psychotria, bignonia, avicennia, anona, and pandanus candelabrum.

The Cape de Verd Islands have, perhaps, a less varied and vigorous vegetation than the coast.

St. Helena, situated in 16° S. lat., has the character of a very poor flora, but of which the members are nearly altogether peculiar. Of 61 species, two or three only have been noticed elsewhere. Ferns, grasses, compositæ, and the cocoa-nut and date-palm, are met with, but the climate is ungenial, and the sugar-cane scarcely thrives. The peak of Diana is elevated 2,692 feet.

Ascension Island is situated in 7° S. lat. The Green Mountain attains 2,818 feet. Some of the caves are verdant with ferns. Grasses are in proportion numerous, and portulacca oleracea, euphorbia origanoides, asclepias curassavica, convolvulus arenarius, and carex pedunculata, overrun the plains.