Prehistoric people cultivated plants for food, medication and other purposes. The ancient Egyptians and Greeks studied the growth, distribution, and cultivation of plants. The first known attempt to classify and describe plants was made about 300 B.C. by the Greek Theophrastus in his two works On the History of Plants and On the Causes of Plants. Pliny the Elder authored Historis Naturalis, where he described the plants he had studied.These works remained standard references through the Middle Ages, when most plant study took place in monasteries and in the botanic gardens of some universities. The period of Renaissance, from 14th to 17th century, was the time modern botany developed. Because of the start of explorations to undiscovered lands, many new plant species were discovered and studied.Books published in the 16th century, called herbais, contained woodcuts of plants, but added little to scientific knowledge. Some attempts at plant classification were made toward the end of the Middle Ages.
The modern scientific study of plants began about the time of the English botanist Nehemiah Grew (1641–1712). He described the production of seeds and wrote an important book on plant anatomy. The invention of the microscope made it possible to study microscopic structures of plants. Marcello Malphigi and Robert Hooke discovered plants cells by studying plants through the microscope.An important step forward was made in the mid-18th century when Carolus Linnaeus established the binominal system of classification. In the late 18th century, Antoine-Laurent de Jussieu, elaborating on his uncle Bernard's work, grouped plants into families according to the number of seed leaves they contained. In the 16th century, Alexander van Humboldt traveled to various destinations across the world and studied the distribution of plants. This was the start of the study of plant geography.As knowledge of plants grew, such practical fields of study as agronomy and horticulture branched off from botany and became separate, but related, sciences.
During the 19th century botanists discovered that plants are composed entirely of cells, and that these cells have individual parts. In the early 1800's, Augustin de Candolle devised a system of plant classification that became the basis of modern taxonomy. Frederick Clements and Robert Wittaker were the pioneers in the field of plant ecology. They studied the relationship between plants and their environment and published their findings in the late 19th century.The theory of evolutionary development of plants gradually gained acceptance after Charles Darwin published his Origin of Species (1859). Gregor Mendel's findings on heredity, reported in 1865 and rediscovered in 1900, became the basis of the science of plant genetics. Luther Burbank showed how improved species and varieties of plants could be bred.
During the 20th century, and particularly since World War II, such other sciences as chemistry, mathematics, and physics have been used to increase botanists' knowledge. Barbara McClintock made important contributions to genetics. New discoveries made through this period convinced some botanists to discard the Linnaean system of plant classification and adopt one based on the evolutionary history of plants. Today, through the efforts of botanists, there exist methods through which weeds can be selectively destroyed, and fruit can be made to ripen before or after its normal time. Plants with certain desired traits have been created using techniques such as hybridization, genetic engineering, and tissue culture. Examples of such plants are high-yield corn and disease-resistant tomatoes.