The only chance of saving a plant that has partially become black and mouldy in the leaf from over-watering, is to place it in a warm room for a week, where the air is dry, so that the water contained in the soil of its pot may evaporate as speedily as possible. If these kinds of plants are kept too short of water in winter, their leaves will, many of them, turn yellow, and drop off. But of the two extremes, (excess of water or the want of it,) this one is comparatively of little moment, because in the spring, presuming the stems and roots to be sound, new shoots clothed with luxuriant foliage will come forth; but on the contrary, if the plant be over-watered, the succulent stem being saturated with moisture, which alow temperature prevents it from throwing off by evaporation, the fibres of the stem decay, and its texture is destroyed. These observations apply to all succulent evergreens.

With respect to the ligneous class of Evergreens, they do not require so large a quantity of water during summer, in proportion to their size, as the succulent; although they also at that season, must be liberally supplied; but in winter, they require more in proportion than the succulent. The great point in ligneous evergreens, is to have a good drainage at the bottom of the pot; and to plant them in a soil of open texture, so that the water may pass freely through it, as soon as it is given to the plant. In winter, these plants will require water in a moderate quantity, perhaps once a week or ten days; but much must depend on the size of the pots. The larger the pot the less frequently will it require water. The camellia, the acacia arnata, corneas and epacris, may be instanced as families to which these remarks apply.

Evergreens should never be allowed to stand in feeders or pans to catch the surplus water, so as to keep the soil in a saturated state.

2d. Deciduous Plants

From the time that this class of plants lose their leaves, until they shoot again, they require but very little water; many will do without it altogether if their pots are of tolerable size, as the moisture contained in the pot when their leaves fall is often enough to keep the roots in a healthy state. Others, and such as are in small pots, will require a moderate supply occasionally, but only just to prevent the soil becoming dust dry. As soon as they show signs of growth, and commence shooting into leaf, water should be very gradually supplied to them, and the quantity increased as their shoots grow and their leaves become developed. As soon as they have acquired a "new coat" of foliage, they should be treated as ligneous evergreens during the summer months. Many deciduous plants are among the roost beautiful we have, and as they do not require much light in their dormant state, they may then be placed in any convenient situation, where they are out of the reach of frost.

3d. Herbaceous Plants

This class require to be watered much on the same system as the succulent evergreens; but in the fall and winter months, particular care should be taken not to allow water to get into the centre of the plants, or into the socket at the base of their leaves; because, unless it quickly evaporates, the water will there become stagnant) and rot the stem of the plant. Many herbaceous plants, with thick large foliage, should, in very hot weather, be shaded the whole of the day, or only have the morning sun for an hour or so.

4th. Bulbous Rooted Plants

Many of this class of plants vegetate and bloom in the fall and winter months. At whatever season of the year a bulb vegetates it should be planted in moist soil; but very little water should be supplied until it has shot up an inch or two; then the water should be given more liberally, and increased in quantitity as the plant grows. When in full bloom, the water may be lessened, (taking care, however, to keep the soil constantly moist) in order the longer to enjoy the beauty of the flower. As soon as it is out of bloom, water must be freely supplied in order to enable the leaves to be matured, and the bulb to become thereby re-established. Most young florists err upon this subject. Upon the proper growth and maturity of the leaves, after bulbous rooted plants are out of bloom, depends the formation of the flower-bud within the bulb for the ensuing year; and unless this important point is duly attended to, no after treatment can induce the blooming of that bulb, until an intervening year's growth of leaves has given the plant the opportunity to form its bloom.

After a plant is out of bloom, therefore, water should be continued in good quantity until the ends of the leaves turn yellow, which, under such circumstances, is a certain indication that the bulb is matured preparatory to its state of rest. This, in common bulbs, as Hyacinths, Narcissus, etc. will be in from one to two months after their bloom. From that period the supply of water should be gradually lessened, and in a few days altogether discontinued. Then the pots may be laid on their sides, when the soil will dry, and the leaves and true roots will wither. The bulbs may then be taken up and put away, to be replanted at the proper season.

5th. Aquatics

Plants of this class are either such as are wholly submerged under the water, throwing their leaves and flowers to the surface, or such as, when in a growing state, like to have their roots only constantly in water. Of the former sort but few enter into the amateur's collection, and they require but little notice, because they either in their natural state remain evergreen, or they retain their submerged situation during their dormant state. The other class of aquatics will, many of them, submit to the ordinary treatment of herbaceous plants whilst in their state of growth. The well known lily of the Nile, or Calla, will serve for an example of them. But this class is much benefitted by having a feeder or dam of water constantly under their pots, for the whole of their season of growth; the ceasstion of which is indicated by the ends of the leaves turning yellow, as with the bulbs. Whilst in a dormant state the soil should be kept just moist; by which term I mean that it should only contain so much water as will allow of its being crumbled between the fingers without adhering to them.

Yours, An Old- Amateur.