Chapter 10 No.10

THE GENUS MELOCACTUS.

(From melon, a melon, and Kaktos, a name applied by Theophrastus to a spiny plant; the species are melon-formed, and their angles are beset with tufts of spines.)

HIS genus forms a group of well-marked and curious plants, with stems similar to those of the globose Echinocactuses and floral characters quite distinct from all other genera. They cannot be said to possess any particular beauty, as their stems are stiff and dumpy, their spines large and rigid, and their flowers small and unattractive. But what is wanting in beauty of form or colour is atoned for in the cap which crowns the stem, and forms the flower-head, growing taller and taller whilst the stem remains stationary, till, under favourable circumstances, a cylindrical mass of spines and hairs, not unlike a large bottle-brush, and 1 ft. or more in length, is developed before the whole plant succumbs to old age. This character belongs more particularly to M. communis, the commonest species, and the one best known in English gardens. Additional interest attaches to this species, from the fact of its having been the first Cactus introduced into Europe, for we are informed that in the year 1581 living plants of the Melon Cactus were known in London. Fifty years later, Gerard, the Adam of English gardening, wrote: "Who can but marvel at the care and singular workmanship shown in this Thistle, the Melocarduus echinatus, or Hedgehog Thistle? It groweth upon the cliffes and gravelly grounds neere unto the seaside in the islands of the West Indies, called St. Margaret's and St. John's Isle, neere unto Puerto Rico, and other places in these countries, by the relation of divers that have journied into these parts who have brought me the plant itself with his seed, the which would not grow ill my garden, by reason of the coldnesse of the clymate." After this, the plant appears to have been frequently cultivated in gardens in this country, and it has only been in recent years that this and similar curiosities have almost disappeared from all except botanical collections.

The most prominent distinctive characters of Melocactus reside in the cap or cluster of spines, wool, and flowers on the summit of the stem. Thirty species are included in the genus, their stems ranging from 1 ft. to 3 ft. in height, the ridges straight, and, as a rule, large; whilst all have stiff stout spines in clusters about 1 in. apart. The small flowers are succeeded by bright red, cherry- like berries, containing numerous black, shining seeds. The distribution of the species is over the hottest parts of some of the West Indian Islands and a few places in Central and South America.

Cultivation.-The cultivation of the several kinds known in gardens is as follows: A tropical temperature all the year round, with as much sunlight as possible, and a moist atmosphere for about three months during summer, when growth is most active. Very little soil is required, as the largest stems have comparatively few roots; indeed, imported stems have been known to live, and even make growth, nearly two years without pushing a single root; but, of course, this was abnormal, and was no other than the using-up of the nourishment stored up in the stem before it was removed from its native home. M. Louis de Smet, a well-known Ghent nurseryman, who grows a fine collection of Cactuses, stated that he had kept M. communis a long time in robust health and growth by feeding it with a very weak solution of salt. Tried at Kew, this treatment did not appear to make any perceptible difference; but, bearing in mind that the Turk's-Cap Cactus is found in great abundance within the reach of sea spray, in some of the West Indian Islands, there seems much reason in M. de Smet's treatment. The same gentleman informed us that he had a specimen of this Cactus bearing no less than thirteen heads. There is, at the time of writing, a specimen at Kew bearing four fine heads. Large imported plants are very rarely, established; and even when established, they do not thrive long, owing to the fact that, after the cap has commenced to form, no further stem-growth is made. Young plants grow very slowly, a plant 3 ft. across taking, according to Sir W. Hooker, from 200 to 300 years to reach that size. It has been stated that grafting is a good plan to adopt for the Melocactus, Mr. F. T. Palmer, in "Culture des Cactées", recommending the following treatment for M. communis: Take a Cereus peruvianus of about the same diameter as that of the base of the Melocactus, cut off the head of the former, but not so low as to come upon the hard, ligneous axis, and then pare off the hard epidermis and ribs for about 1 in. Then take off a slice from the base of the Melocactus, also paring off about 1 in. of the epidermis all round; place the two together, and bind on firmly with strong worsted. In warm weather, a union should take place in about two months, but it will be safest to allow the ligature to remain till growth commences. The precaution of paring off the hard skin and ribs is absolutely necessary, as the juicy centre contracts, and the rind, or epidermis, does not. There would, therefore, be a cavity formed sufficient to prevent all cohesion, be the graft tied on ever so tightly.

Large imported stems should be kept perfectly dry for about a fortnight, and, if they show any signs of rottenness, they should be carefully examined and the bad portions cut away; exposure to the air for a few days will generally cause these pared places to callus over. At all times, even when the stems appear to be in good health, a sharp look-out should be kept for patches of rottenness in the stem, and especially about its base.

Propagation.-This is effected by means of seeds, which usually follow quickly after the flowers produced on cultivated specimens. Multiplication is also possible by means of offsets, which are formed about the base of the stem if the top of a growing plant is cut out. The thirteen-headed plant mentioned above was the result of the removal of the top of a stem which had developed these lateral growths, and thus formed a family of red-capped stems; this had, however, taken place before the plant was removed from its native home. As the cap is the most remarkable part of M. communis, the purchase of large imported stems, in preference to young ones raised from seeds, is recommended; for, as the cap does not form till the stem attains a large size, there would be small hope of seedlings reaching the flowering stage during a lifetime.

SPECIES.

M. communis (common); Fig. 54.-Stem from 2 ft. to 3 ft. in diameter, globose, with from twelve to twenty ridges, and armed with numerous clusters of strong, short spines, the clusters placed closely together. On the summit of the stem is a cylindrical crown, about 4 in. broad, and varying in height from 5 in. to 12 in. This cylinder is composed of a thick pad of whitish, cotton-like substance, through and beyond which a great number of bristle-like red spines are developed, the whole being not unlike a bottle-brush. About the top of this brush-like growth the flowers are produced. These are small, red, fleshy, and tube-shaped, the calyx and corolla forming a regular flower, as in a Hyacinth. They are borne at various times in the year, as long as the cap is growing; afterwards the latter falls off; and the stem rots. We have a cap that was cast by an old plant, and which has stood as an ornament on a shelf in a room for about four years, and is still in perfect condition. In addition to the name of Turk's-Cap Cactus this plant is also known as "Englishman's Head" and "Pope's Head." It is a native of several of the islands of the West Indies, being very abundant in St. Kitt's Island, where it grows in very dry, barren places, often on bare porous rocks.

FIG. 54.-MELOCACTUS COMMUNIS

M. depressus (flattened); Bot. Mag. 3691.-Stem broader than high, deeply cut into about ten broad furrows, along the sharp angles of which are clusters of pale brown spines, from ? in. to 1 in. long, arranged in a star, each cluster 1 in. apart. Instead of the cylinder-like cap of the Turk's-Cap species, this one has a short, broad tuft of white wool and red spines, like a skull-cap. The flowers are small, and soon wither, but remain attached to the oblong berries, which stand erect in a dense cluster in the centre of the cap, and are of a delicate rose-colour. The first introduced plant of this was sent home by Mr. Gardner, who introduced the Epiphyllums and other Cactuses. It flowered on the way to England, and matured its seeds soon after its arrival. It is a native of Pernambuco.

M. Miquelii (Miquel's); Fig. 55.-This species appears to have been introduced in 1838, when two plants of it were sent from the West Indian Island, St. Croix, to the Hamburg Botanic Gardens. The stem is oval, dark green, with fourteen well-defined ribs, as regular as if they had been carved with a knife. The spine-tufts are small; spines short, black-brown, about nine in each tuft, one of which is central, the others radiating; they are less than ? in. long. The "cap" is cylindrical, 3 in. high by 4 in. in diameter, and composed of layers of snow-white threads, mixed with short reddish bristles.

FIG. 55.-MELOCACTUS MIQUELII

These three are the only species of Melocactus that have become known in English gardens, although various other kinds, named M. Lehmanni, M. Zuccarini, M. Ellemeetii, M. Schlumbergerianus, &c., occur in books.

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