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.

The beginnings of modern-style classification systems can be traced to the 1500s–1600s when several attempts were made to scientifically classify plants. In the 19th and 20th centuries, major new techniques were developed for studying plants, includingmicroscopy, chromosome counting, and analysis of plant chemistry. In the last two decades of the 20th century, DNA was used to more accurately classify plants.

Botanical research focuses on plant population groups, evolution, physiology, structure, and systematics. Subdisciplines of botany include agronomy, forestry, horticulture, and paleobotany. Key scientists in the history of botany include Theophrastus, Ibn al-Baitar, Carl Linnaeus, Gregor Johann Mendel, and Norman Borlaug.