THE dwarf habit of the mamil-1arias renders them admirable subjects for window gardening. The best window is one which faces south. In such a position the plants require little attention beyond watering, and they are ever a source of interest and pleasure. The night-blooming cereuses (C. grandiflorus, and others) the old man cactus, phyllocacti, the tender epiphyllums, and, indeed, most other forms of cactuses may, with ordinary care, be successfully grown in a window. Epiphyllums and phyllocacti are among the most popular of our winter and spring-flowering stove and greenhouse plants. The scandent species of cereus are seen to the greatest advantage when trained against a wall or on rafters in a sunny greenhouse. One pendulous species, C. flagelliformis, the rat tail cactus - makes a pretty hanging-basket plant. Cactuses may be placed out-doors in summer without detriment, and a bed of them gives pleasing variety. They should not be turned out of the pots, but plunged, slightly over the rim of the pot, in the soil of the bed or border, which should be at least twelve inches above the ordinary ground level. Water is not so apt to accumulate about the roots to a dangerous extent during wet weather, when the soil is raised in this manner.

The introduction of rocks and boulders among the larger specimens, in outdoor work would add much to their effectiveness.

The culture of cactuses is not commonly understood. The native soil is reproduced with an accuracy that leaves little to be desired, but it is forgotten, or impossible, to supply the native climate. One is useless without the other; and, since the climatic conditions must be artificial, so the soil must be of a character to meet the wants of the plants under the altered circumstances. Rocky or barren sandy mixtures have been proved absolutely worthless for established and healthy growing plants. The mamillarias and other small growing kinds succeed best in a mixture composed of two parts of rich fibrous loam, to one of peat, and one of sand. The more robust kinds thrive better when the mixture contains an additional part of loam. Water is usually applied too sparingly during the growing season, and too freely in winter. The free growing kinds, such as cereuses, phyllocactuses, opuntias, etc., will require water about once a week during the latter period, and for those of slower growth about once a month will be sufficient.

The soil in Which any of the species are planted should not be allowed to become dust dry in summer.

Cactuses shipped from their native soil and climate to more temperate localities should be treated in a peculiar manner. Place them in the sun to dry immediately after unpacking. Two or three days of bright sunshine will suffice to dry them thoroughly; and afterwards they should be planted in dry sand, placed in a position fully exposed to the sun, and kept perfectly dry until growth commences; then they may be potted in the regular compost, and otherwise treated as established plants.

The propagation of cactus plants is generally an easy matter. Any of the species may be grown from seeds; those with elongated stems, such as cereuses, opuntias, epiphyllums, etc., from cuttings of the young growth; and species of maraillaria, and others with short stems, from offsets treated as cuttings. Delicate mamillarias are sometimes grafted upon a cereus of stronger character, while the drooping epiphyllums and cereuses are improved in habit by being grafted upon erect forms of the latter genus. Stocks of Pereskia aculeata are also often used for epiphyllums, with good results.

The seeds may be sown in pots containing sandy loam, at any season of the year, but, preferably, as soon after they are ripe as possible. Keep the soil moist, and the pot covered until germination takes place, when the covering may be removed. If placed in a temperature of eighty degrees, they will germinate in about three weeks; but they may be raised in a much lower temperature, such as that of a room or window, though the process is much slower in such cases. Great care will be required in watering for some time after germination, as the little seedlings advance slowly and are very easily injured by an excess of moisture. When large enough to be handled without difficulty they may be potted separately, and treated in the same manner as older specimens.

Cuttings and offsets should be exposed to sunshine for about a week previous to planting in sandy soil, and subsequently kept perfectly dry, in a warm sunny house, until growth commences. Water may be given in moderate quantity from this time, and increased in volume, according to requirements, as the plants develop. Good roots having been formed, turn out the plants, pot in the ordinary compost, and place them with their elders.

In grafting mamillarias it is simply necessary to cut off the upper portion of the stock, which should be dwarf, so as to leave a smooth horizontal surface at the top. The scion is prepared by removing a portion at the base, which should then correspond with the surface of the stock as nearly as possible. Now place the scion on the top of the prepared stock, and bind it thereto with matting or any other material that will answer the same purpose, just tight enough to keep it securely in position. The object of grafting in this case is to secure for the mamillaria a more perfect root system.

With Cereus flagelliformis and the epiphyllums, as already indicated, it is different. These plants thrive most satisfactorily on their own roots, but larger and more shapely specimens are obtainable by grafting them on tall or erect stocks, and members of the latter genus flower more freely when so treated. The stocks should be grown quickly in such cases, and cut down to the required height, a point which must be determined according to the size of plant desired. If the stock is a cereus, the scions - pieces of the young growth about six inches long, trimmed at the base in the form of a thin wedge - may be inserted in corresponding notches at the top or on the sides, and fastened with a small pin, or, better still, a long prickle of pereskia, or some other cactaceous plant similarly furnished with prominent spines. In the absence of these, the scions may be bound in position as advised in the case of mamillarias. The pereskia stock is usually employed for epiphyllums, when medium-sized specimens are desired; and here the most reliable union is effected by grafting at the top. Scions may be inserted in the top of all branches of a branched pereskia stock with perfectly satisfactory results, provided it be done in the summer, which is the best time for all grafting.

The manual part of the operations having been completed, place the plants in a close atmosphere, and keep them shaded from bright sunshine until a union is brought about. Their after-treatment is similar to that required by plants on their own roots.

The only disastrous disease to which cactuses are subject is a rotting of the stems, induced by a prolonged excess of moisture about the roots, by a severe bruise, or by a continually moist and close condition of the atmosphere in which the plants are grown. When this disease appears the affected portion should be entirely removed with a knife, and, after applying fresh slaked lime or powdered charcoal to the wound, expose it to sunshine till it heals. The soil and atmosphere, in the meantime must be kept severely dry.

Among insects the most troublesome are the green fly, the scale, and the mealy bug. Fumigation with tobacco and subsequent free use of water by means of the syringe will speedily disperse the first-named, but the other two are not so easily banished when they obtain a firm footing. It is strictly unwise to let either of these two pests get a hold in the cactus house, for, when once they gain the shelter afforded by the spines and hairs, their eradication is almost impossible. The best way to get rid of them is to remove all that are accessible with a pointed stick, and then syringe the plants with a mixture prepared as follows: Dissolve four ounces of whale-oil soap in five gallons of tepid water, and to this add as much kerosene as will go in a three-inch pot. These ingredients must be thoroughly mixed before applying with a syringe, and even while that operation is in progress a second person must be employed stirring the mixture vigorously. The object of this stirring is to prevent the kerosene from floating on top. Care should be taken to keep the preparation from reaching the roots, and also to syringe the plants thoroughly with clean water about thirty minutes after its application.

It would be well to treat the plants, whether or not infested, periodically as here described, merely as a preventive measure.

We have now dwelt upon the more important cultural requirements of these curious plants. It should be remembered, however, that the instructions are general and that particular cases must occur in which they will not be applicable. This refers more especially to the matter of watering, when so much depends upon local conditions. When the majority of these plants are established and thrive in a given position, they are hard to kill, but continued neglect will do its work anywhere, and in such cases the strongest efforts of even the foremost specialists would be wholly futile.

Edward Bowen.