Citron, or Citrus, L. an exotic genus of plants, comprising six species; of which the following are occasionally reared in hot-houses :

1. The Medica, or Citron-tree, which is a beautiful evergreen, rises from five to ten feet in height, and forms a full head, thickly set with leaves. It is very luxuriant in its vegetation, shooting forth a profusion of sweet flowers in the spring, and early in the summer, which are frequently succeeded by an abundance of fruit, that arrives, sometimes, at tolerable perfection.

This species is originally obtained by seed; but the most certain method of propagating it, is by budding it on stocks raised from seeds to a proper size. These may be sown, in March, in pots of rich light earth, half an inch deep, and plunged in a hot-bed under frames and glasses, being occasionally watered. Towards the middle of June, they may be exposed to the open air, in which they should remain till October, when they are to be removed to the green-house till the ensuing spring. In the month of March, or April, following, they Will be fit to be transplanted, singly, in small pots, care being taken to water them immediately after that operation is performed, and to repeat it when necessary; so mat, in the course of a year, or two, the largest of those designed for stocks will be fit for budding. Previously to their being planted, they must be set for a day or two in tubs of water, to plump their bark and roots. Next, they should be washed and cleaned, the roots freed from diseased parts and all the small dried fibres. They are then to be planted in pots filled with light earth, and plunged in a tan-bed, where they should remain for three or four months; after which they may be exposed to the open air, but will bear it only from the end of May to the middle of October.

The fruit of the citron-tree yields a very agreeable acid, which is of considerable utility in medicine, particularly as an antiscorbutic— See Lemon-Juice.

There is another variety of this species, growing abundantly in the British West India Islands, producing a spherical fruit of a much smaller size than the lemon, and containing an acid juice, in a more concentrated state. - See Limes.

2. The Aurantium. See Orange.

3. The Decumana, or the Giant Citron, which is common in the East and West Indies, and produces a fruit, sometimes 14 lb. in weight, containing a sweet pulp, and small compartments in the centre, which abound with a subacid vinous juice. As it requires nearly two years to arrive at maturity, in the climate of Europe, it is ' seldom cultivated.