CACTUS. This word, applied in the form of kaktos, by the ancient Greeks to some prickly plant, was adopted by Linnaeus as the family title of a group of curious succulent 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 Linnaeus, the name Cactus is almost conterminous with what is now regarded as the natural order Cactaceoe, which embraces several modern genera. It is one of the fewLinnaean 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 of 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, comparatively 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 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 form their high colouring. In one group, represented by Cereu, they consist of a tube, more or less elongated, on the outer surface of which, towards the base are developed small and at first inconspicuous 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 center. 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 subdivisions, which are separated by the differences in the flower-tube just explained. Those with long-tubed flowers, the Cacteoe tubulosoe, form the genera Melocactus, Mammillaria, Echinocactus. Cereus, Pilocereus, Echinopsis, Phyllocactus, Epiphyllym, &c., while those with short-tubed flowers, the Cacteoe rotatoe, are referred to Rhispsalis, Opuntia, Pereskia, and one or two of minor importance. These plant, whether viewed as the cactus family or the natural order Cacteoe or Cactaceoe, 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.
MELOCACTUS, the family of Melon-thistle or Turks-cap Cactuses, contains, according to Labouret, a monographer of the order,, about thirty species, which inhabit chiefly the West Indies, Mexico, and Brazil, a few extending into New Granada. The typical species, M. communis, forms a succulent mass of roundish or ovate form, from 1 foot to 2 feet high, the surface divided into numerous furrows like the ribs of a melon, with projecting angles, which are set with a regular series of stellated spines,-each bundle consisting of about five larger spines, accompanied by smaller but sharp aculei or bristles, - and the tip of the plant being surmounted by a cylindrical crown called a cephalium, 3 to 5 inches high, composed of reddish-brown acicular bristles, closely packed with cottony tomentum. At the summit of this crown the small rosy-pink flowers are produced, half protruding from the mass of wool, and these are succeeded by small red berries. These strange plants usually grow in rocky places with little or no earth to support them; and it is said that in times of drought the cattle resort to them to allay their thirst, first ripping them up with their horns and tearing off the outer skin, and then devouring the moist succulent parts. The fruit, which has an agreeably acid falvour, is frequently eaten in the West Indies. The Melocacti are distinguished by the distinct cephalium or crown which bears the flowers.
MAMMILLARIA. This group, which comprises nearly 300 species, mostly Mexican, with a few Brazilian and West Indian, is called Nipple Cactus, and consists of globular or cylindrical succulent plants, whose surface instead of being cut up into ridges with alternate furrows, as in Melocactus, is broken up onto teat-like cylindrical or angular tubercles, spirally arranged, and terminating in a radiating tuft of spines which spring from a little woolly cushion. The flowers issue from between the mammillae, towards the upper part of the stem, often disposed in a zone just below the apex, and are either purple, rose-pink, white, or yellow, and of moderate size. The spines are variously coloured, white and yellow tints predominating, and from the symmetrical arrangement of the areolae or tufts of spines they are very pretty objects, and are hence frequently kept in drawing-room plant cases.
ECHINOCACTUS is the name given to the group bearing the popular name of Hedgehog Cactus. It comprises some 200 species, of which more than half are natives of Mexico, and the rest are scattered through South America, extending as far south as Buenos Ayres. They have the fleshy stems characteristic of the order, these being either globose, oblong, or cylindrical, and either ribbed as in Melocactus, or broken up into district tubercles, and most of them armed with stiff sharp spines, set in little wooly cushions occupying the place of the buds. The flowers, produced near the apex of the plant, are generally large and showy, yellow and rose being the prevailing colours. They are succeeded by succulent fruits, which are exserted, and frequently scaly or spiny, in which respects this genus differs both from Melocactus and Mammillaria, which have the fruits immersed and smooth. One of the most interesting species is the E. Visnaga, of which some very large plants have been from time to time imported. A specimen weighing one ton, and measuring 9 feet high, and 3 feet in diameter, was received at Kew some years since, but owing to injuries received, during transit, it did not long survive. These large plants have from forty to fifty ridges, on which the buds and clusters of spines are sunk at intervals, the aggregate number of the spines having been in some cases computed at upwards of 50,000 on a single plant. These spines are used by the Mexicans as toothpicks, whence the name Visnaga.
CEREUS. This group bears the trivial name of Torch Thistle. It comprises about 150 species, scattered through South American and the West Indies. In one series, numbering between twenty and thirty species, sometimes separated under the name of Echinocereus, the stems are short, branched or simple, divided into few or many ridges, all armed with sharp formidable spines; but in the greater number of species the stems are columnar or elongated, some of the latter creeping on the ground or climbing up the trunks of trees, eooting as they grow. One of the former group, C pectinatus, produces a purplish fruit resembling a gooseberry, which is very good eating; and the fleshy part of the stem, itself, which is called Cabeza del Viego by the Mexicans, is eaten by them as a vegetable after removing the spines. To the latter group belongs C. giganteus, the largest and most striking species of the genus, a native of hot arid desert regions of New Mexico, growing there is rocky valley and on mountain sides, where the tall stems, with their erect branches have the appearance of telegraph poles. The stems grow to a height of from 50 feet to 60 feet, and have a diameter of from 1 foot to 2 feet, often unbranched, but sometimes furnished with branches which grow out at right angles from the main stem, and then curve upwards and continue their growth parallel to it; these stems have from twelve to twenty ribs, on which at intervals of about an inch are the buds with their thick yellow cushions, from which issue five or six large and numerous smaller spines. The fruits of this plant, which are green oval bodies from 2 to 3 inches long, contain a crimson pulp from which the Pimos and papagos Indians prepare an excellent preserve; and they also use the ripe fruit as an article of food, gathering it by means of a forked stick attached to a long pole. The Cereuses include some of our most interesting and beautiful hothouse plants.
PILOCEREUS, the Old Man cactus, forms a small group with tallish erect fleshy angulate stems, on which, with the tufts of spines, are developed hair-like bodies, which though rather coarse, bear some resemblance to the hoary locks of an aged man. The plants are nearly allied to Cercus, differing chiefly in the floriferous portion developing these longer and more attenuated hair-like spines, which surround the base of the flowers, and form a dense woolly head or cephalium. The most familiar species is P. senilis, a Mexican plant, which though seldom seen more than a foot or two in height in greenhouses, reaches from 20 feet to 30 feet in its native country.
ECHINOPSIS is another small group of species, separated by some authors from Cercus. They are dwarf, ribbed, globose, or cylindrical plants; and the flowers, which are produced from the side instead of the apex of the stem, are large, and in some cases very beautiful, being remarkable for the length of the tube, which is more or less covered with bristly hairs. There are about thirty species known, their geographical range extending from Mexico and Texas to Brazil, Bolivia, and Chili.
PHYLLOCACTUS, the Leaf cactus family, consists of about a dozen species, found in Mexico and Brazil. They differ from all the forms already noticed in being shrubby and epiphytal in habit, and in having the branches compressed and dilated so as to resemble thick fleshy leaves, with a strong median axis, and terete woody base. The margins of these leaf-like branches are more or less crenately notched, the notches representing buds, as do the spine-clusters in the spiny genera; and from these crenatures the large showy flowers are produced. As garden plants the Phyllocacti are amongst the most ornamental of the whole family, being of easy culture, free blooming, and remarkably showy, the colour of the flowers ranging from rich crimson, through rose-pink, to creamy white. They are often called Peiphyllum, which name is, however properly restricted to the group next to be mentioned.
EPIPHYLUM. This name is now restricted to two or three dwarf branching Brazilian epiphytal plants of extreme beauty, which agree with Phyllocactus in having the branches dilated into the form of fleshy leaves, but differ in having them divided into short truncate leaf-like portions, which are articulated, that is to say, provided with a joint by which they separate spontaneously; the margins are crenate or dentate, and the flowers, which are large and showy, magenta or crimson, appear at the apex of the terminal joints. In E. truncatum the flowers have a very different aspect from that of other acteoe, from the mouth of the tube being oblique and the segments all reflexed at the tip. The short separate pieces of which these plants are made up grow out of each other, so that the branches may be said to resemble leaves joined together endwise.
RHIPSALIS, a genus of about thirty tropica. American species, contains some of the plants once referred to Cactus. It is a very heterogeneous group, being fleshy-stemmed with a woody axis, the branches being angular, winged, flattened, or cylindrical, and the flowers small, short-tubed, succeeded by small, round, pea-shaped berries. Rhipsal;is Cassytha, when seen laden with its white berries, bears no inconsiderable resemblance to a branch of mistleto. All the species are epiphytal in habit.
OPUNTIA, the prickly Pear, or Indian Fig Cactus, is a large typical group, comprising some 150 species, found in North America, the West Indies, and warmer parts of South America, extending as far as Chili. In aspect they are very distinct from any of the other groups. They are fleshy shrubs, with terete woody stems, and numerous succulent branches, composed in most of the species of separate jointsor parts, which are much compressed, often elliptic or suborbicular, dottel over in spiral lines with small fleshy caduceus leaves, in the exiles of which are placed the areoles or tufts of glochidiate or hooked spines of two forms. The flowers are mostly yellow or reddish-yellow, and they are succeeded by pear-shaped or egg-shaped fruits, having a broad scar at the top, furnished on their soft fleshy rind with tufts of small spines. The sweet juicy fruits of O. vulgaris and O. Tuna are much eaten under the name of prickly pears, and are greatly esteemed for their cooling properties. Both these species are extensively cultivated for their fruit in Southern Europe, the Canaries, and Northern Africa, and the frits are not unfrequently to be seen in Covent Garden Market and in the shops of the leading fruiterers of the metropolis.
The cochineal insect is nurtured on a species of Opuntia (O. coccinellifera), separated by some authors under the name of Nopalca, and sometimes also on O. Tuna. Plantations of the nopal and the tuna, which are called nopaleries, are established for the purpose of rearing this insect, the Coccus cacti, and these often contain as many as 50,000 plants. The females are placed on the plant about August, and in four months the first crop of cochineal is gathered, two more being produced in the course of the year. The native country f the insect is Mexico, and it is there more or less cultivated; but the greater part of our supply comes from New Granada and the Canary Islands.
PERESKIA ACULEATA, or Barbados Gooseberry, the cactus Pereskia of Linnaeus, is the only remaining generic type; and this differs from the rest in having woody stems and lead bearing branches, the leaves being somewhat felshy, but otherwise of the ordinary laminate character. The flowers are subpaniculate, white or yellowish. This species is frequently used as a stock on which to graft other Cacti. There are about a dozen species known. (T.MO.)
The above article was written by Thomas Moore, F.L.S.; formerly Curator of the Apothecaries' Company's Garden at Chelseam 1848-87; edited the Gardeners' Magazine of Botany; author of Handbook of British Ferns; Index Filicum; and Illustrations of Orchidaceous Plants.