The beautiful orange tree (citrus vulgaris) belongs to the natural order of the Aurantiacm, being closely related to the lemon, lime, bergamot and others, and indigenous to all parts of southern Europe, and extensively cultivated in Sicily, Calabria, Nice in France, and also in Spain and Portugal. There are two varieties of orange trees: the citrus aurantium Risso, producing the sweet orange, and citrus bigaradia Duham, producing the bitter orange.

From the orange tree are obtained several valuable essential oils.

1. The true orange-flower essence, obtained by maceration of the flowers with lard (enfleurage), and extracting, employed in perfumery.

2. Oil of orange flowers, or oil of neroli: a. oil neroli petale, by distilling the flowers of the sweet orange tree; b. oil neroli bigarade, obtained from the bitter orange tree.

3. Oil neroli petitgrain, obtained by distilling the leaves and unripe fruits.

4. Oil of orange peel (oil of Portugal).

The oils of 2, 3 and 4 are all employed in the manufacture of carbonated beverages.