The leaves from the Citrus aurantium var. Amara tree provide Petitgrain, and the fruit peel provides us with Bitter Orange oil. When steam distilled, a tonne of flowers provide roughly 1 kilo of Neroli. A by-product of the process is Orange Flower Water, which can be further processed to obtain Orange Flower Water Absolute.
If the flowers are solvent extracted instead of steam distilled, the result is Orange Flower Concrete and Orange Flower Absolute. All of these materials show how versatile the bitter orange tree is in perfumery.
Aromatically, Neroli differs from orange blossom, being slightly green, a little soapy and more breezy. Orange blossom is richer and honeyed. Both pair well in a composition, being often used in white florals, colognes and oriental floral scents.