INTRODUCTION Chemical plant taxonomy or chemotaxonomy of plants may be defined as a scientific investigation of the potentialities of chemical characters for the study of problems or plant taxonomy and plant phylogeny. Plant taxonomy is the science or and naming appropriately taxa t and describing arranging them in a natural system or planta. Principles of were elaborated in the past century by chemotaxonomy P. De Candolle and by GreshofP Candalle put forward two postulates: (i) Plant taxonomy will be the most useful guide to man in his search for new industrial and medicinal plants; Chemical characteristio of plants will be most valuable to plant taxonomy in the future. While the frst postulate of De candore proved to be extremely fruitfl and has been applied repeatedly when new sources or promising plant constituents are to be detected, his second postulate came to be accepted Researchers like Rochleder3, Colin Greshom. very slowly. Rosenthalers, Baker and Smith, Wheldale. Iwanow Moltsch10, McNair and Veevers were enthusiastic but rather isolated workers the field of chemotaxonomy However, the fact that the first postulate of De Candolle was a pplied very successfully by generations of phytochemists forms an indirect proof of the validi his second postulate. Some examples may serve to illustrate just the services plant taxonomy when the renders to chemists interested in distinct types or plant corstituents pharmaceutical industry became interested in plant steroids as starting materials for hormone synthesis, the search for suitable sources was essentially guided by taxonomic concepts The genus without exception, to accumulate smphantku was investigated first for cardenolides and its species Proved, members this category of Thousands of species were screened for steroidai sapo- phytoconstituents. Benins and in the taxa already known to contain them, ia in Agwaczac and Liliacem by far the highest frequency of occurrence was observed in recent years the alkaloids have begun to pregnanederived attract attention. Such alkaloid-like substances had been known for several years to be present in the apocynaceous genus Holankna. In this instance too, an alliance of genera induded by taxonomists in the plant family 4oonasear proved to be most promising for exploration. very recently Taxon plural: taxa) is the name for a taxonomic entity of erm may be applied to any mtemaue entity(pea genus amly, etc.) 173