Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/697

Rh heavy floods. It contains a town-house, a prison, a con vent of Carmelites, and some live or six churches, and carries on an active trade in tobacco, coffee, and sugar. Population 15,000.

 CACONGO, a small kingdom of Western Africa, sepa rated from Congo by the river Zaire. The surface is mountainous but fruitful, the climate healthy though un- suited for Europeans. A strong tendency to adopt Europ ean customs and conveniences is displayed by the inhabi tants, who carry on a considerable trade at the seaport towns of Mallemba and Cabinda. The capital is Kinguela.  CACTUS. This word, applied in the form of [ Greek ] by the ancient Greeks to some prickly plant, was adopted by Linnaeus as the family title of a group of curious suc culent or fleshy-stemmed plants, most of them prickly and leafless, some of which produce beautiful flowers, and are now so popular in our gardens that the name has become familiar. As applied by Linnauis, the name Cactus is almost conterminous with what is now regarded as the natural order Cactacea*, which embraces several modern genera. It is one of the few Linnaaan generic terms which have been entirely set aside by the names adopted for the modern divisions of the group. The Cacti may be described in general terms as plants having a woody axis, overlaid with thick masses of cellular tissue forming the fleshy stems. These are extremely various in character and form, being globose, cylindrical, columnar, or flattened into leafy expansions or thick joint-like divisions, the surface being either ribbed like a melon, or developed into nipple-like protuberances, or variously angular, but in the greater number of the species furnished copiously with tufts of horny spines, some of which are exceedingly keen and powerful. These tufts show the position of buds, of which, however, compara tively few are developed. The stems are in most cases leafless, using the term in a popular sense ; the leaves, if present at all, being generally reduced to minute scales. In one genus, however, that of Pereskia, the stems are less succulent, and the leaves, though rather fleshy, are developed in the usual form. The flowers are frequently large and showy, and are generally attractive from their high colouring. In one group, represented by Ccretts, they consist of a tube, more or less elongated, on the outer surface of which, towards the base, are developed small and at first incon spicuous scales, which gradually increase in size upwards, and at length become crowded, numerous, and petaloid, forming a funnel-shaped blossom, the beauty of which is much enhanced by the multitude of conspicuous stamens which with the pistil occupy the centre. In another group, represented by Opuntia, the flowers are rotate, that is to say, the long tube is replaced by a very short one. At the base of the tube, in both groups, the ovary becomes developed into a fleshy (often edible) fruit, that produced by the Opuntia being known as the prickly pear or Indian fig. The principal modern genera are ranged under two sub divisions, which are separated by the differences in the flower-tube just explained. Those with long-tubed flowers, the Cactew titbuloscp, form the genera Melocactus, Nam- millaria, Echinocactns, Cereits, Pilocereus, Echinopsis, Phyllocact/ts, Epiphyllum, &c. ; while those with short- tubed flowers, the Cacteoe rotatce, are referred to Rhipsalis, Opuntici, PercsMa, and one or two of minor importance. These plants, whether viewed as the Cactus family or the natural order Cacteai or Cactacccc, belong almost entirely, if not exclusively, to the New World ; but some of the Opuntias have been so long distributed over certain parts of Europe, especially on the shores of the Mediterranean and the volcanic soil of Italy, that they appear in some places to have taken possession of the soil, and to be distinguished with difficulty from the aboriginal vegetation. The habitats which they affect are the hot dry regions of tropical America, the aridity of which they are enabled to withstand in consequence of the thickness of their skin, and the paucity of evaporating pores or stomates with which they are furnished, these conditions not permitting the moisture they contain to be carried off too rapidly. Occurring thus as they do in situations where ordinary vegetation could not exist, they may be considered as one of the means which nature has provided for the support of man and animals where other means of subsistence fail. The stems are filled with wholesome though insipid fluid, and the succulent fruit are not only edible but agreeable. In fevers the fruits are freely administered as a cooling drink, and when bruised are regarded as a valuable remedy for the cure of ulcers. The Spanish Americans plant the Opuntias around their houses, where they serve as impenetrable fences.

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