Review

The commodity group Exudates (defined as the fluids that ooze out of a wound of a tree) is divided into three groups of substances: Resins, Latex, and Gums. Resins, usually mixes of terpenes, are primarily used in paints and varnishes. Latex, of which the most important is rubber, is used in car tyres, engineering components and consumers goods, including chewing gum. The main components of latex are polyisoprenes and resins. Vegetable gums consist of mixtures of polysaccharides and are often used in cosmetics, soaps, and in food products as stabiliser or emulsifier. For the field botanist exudate is a useful character. However, this use is not mentioned in the PROSEA volume. The introduction, where the properties of the exudates are discussed, is followed by the treatment of genera and species. Major exudate-producing species are treated in full (Chapter 2), minor species only briefly (Chapter 3), while Chapter 4 lists species with other primary uses. References, a glossary, and an index complete the volume.