MELOCACTUS

melocactus, the genus of melon-thistle or turk's-cap cactuses, contains, according to a recent estimate, about 90 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 ft. to 2 ft. 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 bristles--and the tip of the plant being surmounted by a cylindrical crown 3 to 5 in. high, composed of reddish-brown, needle-like bristles, closely packed with cottony wool. 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 flavour, is frequently eaten in the west indies. the _melocacti_ are distinguished by the distinct cephalium or crown which bears the flowers. mammillaria.--this genus, 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 into 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. they grow freely in a cool greenhouse. [illustration: fig. 2.--_echinocactus_ much reduced; the flowers are several inches in diameter.] echinocactus (fig. 2) is the name given to the genus bearing the popular name of hedgehog cactus. it comprises some 200 species, distributed from the south-west united states to brazil and chile. 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 distinct tubercles, and most of them armed with stiff sharp pines, set in little woolly 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 _mamrmllaria_, which have the fruits immersed and smooth. one of the most interesting species is the _e. ingens_, of which some very large plants have been from time to time imported. these large plants have from 40 to 50 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. the plants are slow growers and must have plenty of sun heat; they require sandy loam with a mixture of sand and bricks finely broken and must be kept dry in winter. cereus.--this group bears the common name of torch thistle. it comprises about 100 species, largely mexican but scattered through south america and the west indies. the stems are columnar or elongated, some of the latter creeping on the ground or climbing up the trunks of trees, rooting as they grow. _c. giganteus_, the largest and most striking species of the genus, is a native of hot, arid, desert regions of new mexico, growing there in rocky valleys 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 ft. to 60 ft., and have a diameter of from 1 ft. to 2 ft., often unbranched, but sometimes furnished with branches [v.04 p.0926] 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 in. 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. in the allied genus _echinocereus_, with 25 to 30 species in north and south america, the stems are short, branched or simple, divided into few or many ridges all armed with sharp, formidable spines. _e. 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.