Linnaeus, Carolus (1707–1778), a Swedish naturalist. Linnaeus developed systematic methods for classifying and naming plants and animals. He devised the classifications of class, order, genus, and species, and established as standard the binomial (two-name) system for giving scientific names to plants and animals.

The scientific names in Linnaeus' Species Plantarum (1753) and Systema Naturae (1758), standard references in his age, served as the basis for modern botanical and zoological nomenclature. Linnaeus realized that man was an animal and placed him in the order of primates, giving him the scientific name Homo sapiens. Linnaeus classified thousands of plant species, assigning plants to 24 classes according to the number and position of their stamens and pistils. Although later botanical knowledge revealed that this system was inadequate, it did lay the foundation for the science of plant taxonomy.

At first, Linnaeus, like his contemporaries, believed that each species of plant and animal had been created separately and that no species had become extinct and no new species had been created since the beginning of time. Later, however, in Plantae Hybridae (1751), Linnaeus suggested that new plant species had indeed developed, through hybridization. He thus deserves a place in the early history of the concept of evolution.

Linnaeus was the son of a clergyman. He attended the universities of Lund and Uppsala. In 1732 he traveled to Lapland, studying arctic plant and animal life. He received a medical degree in 1735 from the University of Harderwijk in Holland, and returned to Stockholm in 1738. After 1742 Linnaeus was a professor of botany at the University of Uppsala, where he attracted students from other countries. In 1761 he was made a nobleman and took the name Carl von Linné.

Linnaeus published more than 180 books. After his death, his papers and botanical collection were purchased by English admirers, who established the Linnaean Society of London, a biological association. Linnaeus' enthusiasm for botany inspired a whole generation of amateur naturalists, including such men as Wordsworth and Goethe.