a genus of plants belonging to the class pentandria and order digynia, and in the natural orders arranged under the Succulente. See Botany Index.—This singular tribe of plants is peculiar to the sandy deserts of Africa and Arabia. They are extremely succulent. From this peculiarity of structure, the power of retaining water to support and nourish them, they are enabled to live during the prevalent droughts of those arid regions. On this account the stapelia has been compared to the camel; and we are told that, by a very apt similitude, it has been denominated "the camel of the vegetable kingdom." We must confess ourselves quite at a loss to see the propriety or aptitude of this comparison. In many parts of the animal and vegetable economy there is doubtless a very obvious and striking analogy; but this analogy has been often carried too far; much farther than fair experiment and accurate observation will in any degree support. It is perhaps owing to this inaccuracy in observing the peculiarity of structure and diversity of functions, that a resemblance is supposed to exist, as in the present case, where in reality there is none. The camel is provided with a bag or fifth stomach, in addition to the four with which ruminant animals are furnished. This fifth stomach is destined as a reservoir to contain water; and it is sufficiently capacious to receive a quantity of that necessary fluid, equal to the wants of the animal, for many days: and this water, as long as it remains in the fifth stomach, is said to be perfectly pure and unchanged. The Stapelia, and other succulent plants, have no such reservoir. The water is equally, or nearly so, diffused through the whole plant. Every vessel and every cell is fully distended. But besides, this water, whether it be received by the roots, or absorbed from the atmosphere, has probably undergone a complete change, and become, after it has been a short time within the plant, a fluid possessed of very different qualities.

The peculiar economy in the stapelia, and other succulent plants, seems to exist in the absorbent and exhalant systems. The power of absorption is as much increased as the power of the exhalant or perspiratory vessels is diminished. In these plants, a small quantity of nourishment is required. There is no solid part to be formed, no large fruit to be produced. They generally have very small leaves, often are entirely naked; so that taking the whole plant, a small surface only is exposed to the action of light and heat, and consequently a much smaller proportion of water is decomposed than in plants which are much branched and furnished with leaves.

Two species of stapelia only were known at the beginning of the century. The unfortunate Forkal, the companion of Niebuhrr, who was sent out by the king of Denmark to explore the interior of Arabia, and who fell a sacrifice to the pestilential diseases of those inhospitable regions, discovered two new species. Thunberg, in his Prodromus, has mentioned five more. Forty new species have been discovered by Mr Masson of Kew Gardens, who was sent out by his present Majesty for the purpose of collecting plants round the Cape of Good Hope. Descriptions of these, with elegant and highly finished coloured engravings, have lately been published. They are chiefly natives of the extensive deserts called Karro, on the western side of the Cape.