Botany plant science or plant biology from Ancient Greek botane pasture, or fodder and that from to feed or to graze" a discipline of biology, is the science of plant life. Traditionally, the science included the study of fungi, algae, and viruses. A person engaged in the study of botany is called a botanist.Botany covers a wide range of scientific disciplines . including structure, growth, reproduction, metabolism, development, diseases, chemical properties, and evolutionary relationships among taxonomic groups. Botany began with early human efforts to identify edible, medicinal and poisonous plants, making it one of the oldest branches of science. Nowadays, botanists study about 400,000 species of living organisms.