ABSTRACT
The recognition and application of phytochemistry in plant taxonomy could be said to have started from the early man. Man began to classify plants as edible and nonedible, aromatic, colorful, tasty, and medicinal obviously based on their chemical constituents and such grouping of characters has been attributed to their differences in chemical diversity. Chemotaxonomy is a system of taxonomy that classifies organisms based on their chemical constituents. Phytochemical markers of taxonomic importance include the directly visible particles (including crystals, raphides, and starch granules), primary metabolites, and the secondary metabolites. In this chapter, the authors detailed the concept and origin of chemotaxonomy and the different classes of phytochemicals that have been successfully utilized in classifica-tion and delimitation of plants at all taxonomic levels. The challenges and limitations of this branch of science and suggestions of possible remedies were also highlighted. Researchers and students in the fields of plant 198taxonomy, phytochemistry, and natural products chemistry will find this chapter exceptionally relevant.
