A vast array of natural organic compounds, the products of primary and secondary metabolism, occur in plants. This dictionary provides basic information, including structural formulae, on plant constituents. It profiles over 3000 substances from phenolics and alkaloids through carbohydrates and plant glycosides to oils and triterpenoids. For each substance, the author presents the trivial name, synonyms, structural type, chemical structure showing stereochemistry, molecular weight and formula, natural occurrence, biological activity and commercial or other use. Key references are provided for each class and subclass.