Fourteen species. Greenhouse evergreen fruit trees or shrubs, budding or grafting, and sometimes cuttings. Rich loamy soil mixed with dung.

For the structure of a house suitable for their cultivation, see Orangery. The following extracts from an essay by Mr. Jones, gardener at Knowsley, exhibits the successful practice in cultivating this genus, pursued by Mr. Durden, gardener at Hurst House, Lancashire.

Varieties

Those who wish to cultivate the orange tree for the sake of the fruit, ought to be very careful in making a selection of sorts, especially of sweet oranges.

The best way, perhaps, is to procure grafts or young plants from such varieties as have proved themselves to be good in other establishments, or proved plants from a nursery.

Soil

Too much attention cannot be paid to the soil; its principal features ought to be lightness, richness, and openness of texture, and unless it possess these qualities it is unfit for the orange tribe.

Water

This must at all times be sparingly administered, especially if the trees are kept in a high moist temperature. Occasionally give a little weak liquid manure.

Temperature

It is doubtless an erroneous opinion, that if the atmospheric temperature is 8° to 10° above the freezing point during winter, and is never allowed to rise above 70° or 80° during summer, that the orange tribe, other circumstances being favourable, may be cultivated successfully. Mr. Durden never allows the temperature of his house to fall below 50° during the winter season, and during summer retains a moist atmosphere of 80o or 90°.

After-Culture

In pruning, if the plants are trained on trellises, the branches should be kept thin to allow the greater part of the leaves to be exposed to the sun. The fruit is generally produced at the tips of the small spurs or brackets; therefore it would be a positive injury to the crop to shorten-any of these spurs, except it is desirable to increase their number. The operation of pruning is performed at any time when it appears to be necessary, always, however, taking care to have a succession of young wood coming in. In thinning the fruit, particular attention ought to be paid to the state of the tree, for the quantity of fruit must be entirely regulated by the vigour of the tree; no better rule can be laid down than that for governing the operation of thinning.

If a tree appears debilitated in the extreme, it must not be allowed to carry any fruit for an entire season.

One cause of debility is, allowing the fruit to remain long after it is ripe. Of that required for confectionary purposes a larger quantity may be left on the trees, but it must always be proportioned to the capabilities of the tree.

Cleaning The Plants

The greatest attention should be paid to cleanliness; the consequences of allowing insects to overrun a collection of plants are familiar to every one acquainted with gardening.

"The aphis attacks the tender shoots and young leaves; the red spider the more advanced foliage; and the coccus hesperidum every part of the plant.

"Almost every gardener has his peculiar nostrum for destroying these animals; but a good preventive is cleanliness in everything about the plants.

"The coccus may be brushed off, using a brush that is no harder than is just necessary to remove the insect.

"For the thrips red spider, and aphis, a sponge and clean water will remove them all, if used before the insects have become very numerous.

"Fumigation should never be resorted to except in extreme cases.

"The leaves should also be cleaned with a damp sponge as often as they appear clogged by dust adhering to the resinous exudations on their surface." - (Card. Chron. - Gard. Almanack).