Linnaeus, Carolus

Swedish Botanist 1707-1778

Swedish botanist Carolus Linnaeus is best remembered for his classification system and binomial system of nomenclature. He brought order to the chaotic state of biological knowledge in the eighteenth century, introducing a systematic means of processing and organizing information on plants and animals. His particular interest was in plants, especially flowering plants, and the bulk of his efforts and publications focused on botanical studies. His most lasting contribution to biology is his binomial nomenclatural system, which grew out of what was for him a more primary focus: the development of a comprehensive system for classifying plants and animals.

Also known as Carl Linnaeus or Carl von Linné, he was born in Små-land, Sweden, and even in his early years displayed an unusual interest in plants. His father, a curate in the Lutheran church, taught him many plant names. In adolescence Linnaeus learned about the doctrine of sexual reproduction in plants, which at that time was still a relatively recent concept. While still a medical student at universities in Lund and Uppsala, he began to develop a classification system based on the reproductive organs of plants. Faculty recognized his abilities and asked him to conduct lectures on botany. In 1732 he received support from the Swedish Royal Academy of Science to travel to Lapland to observe the plants and animals there and how people lived and supported themselves. This trip made a lasting impression on young Linnaeus. He wrote about the plants he observed in Flora Lapponica (1737), and the specimens he collected in Lapland are now at the Institut de France, Paris.

In 1735 Linnaeus traveled to Holland to get a medical degree at Hard-erwijk. While in Holland he met prominent naturalists and was able to publish some of his own research. He made short trips to England, Germany, and France, again meeting important naturalists. In Holland he worked for George Clifford, a wealthy merchant with an extensive private botanical garden, which Linnaeus worked on and catalogued. This opportunity exposed Linnaeus to a wide range of plants that he would not have seen in his native Sweden, an experience that aided him in developing his ideas about classification. A catalogue of plants in Clifford's garden was published as Hortus Cliffortianus (1738).

Among the ten manuscripts Linnaeus published while in Holland were Systema Naturae (1735) and Genera Plantarum (1737). The former contained the first appearance of his classification scheme, while the latter contained his natural definitions of genera , building on work previously done by Joseph Pitton de Tournefort (1656-1708) and others.

Linnaeus returned to Sweden in 1738, was married, and practiced medicine in Stockholm for three years. In 1741 he was appointed a professor at the university in Uppsala, where he remained for the rest of his life, teaching, collecting and studying plants, and publishing. He was popular with his students and trained among them many enthusiastic naturalists. Early in his university career he traveled around Sweden, but after 1749 he stayed in Uppsala, sending a number of his students out on plant exploration journeys to many parts of the world. His landmark Species Plantarum (1753) and many other publications trace the development of his thought through the course of his career.

Linnaeus received many honors during his lifetime and was famous in Sweden and abroad for his ideas about classification and nomenclature. The eighteenth century was marked by a collective desire to gather and organize the whole of knowledge in encyclopedic schemes, and certainly Linnaeus's efforts were in harmony with the spirit of his times. His unusual talents for systematic organization and for intuiting the relationships among plants allowed him to accomplish a methodical review and theoretical organization of the natural world on a massive scale at a time when such work was desperately needed. His precise terminology, use of an international language, and global scope ensured widespread applicability and usability of his system. Modern systematic biology began with his mid-eighteenth-century publications. Historians of science recognize this by referring to earlier publications in the life sciences as "pre-Linnaean literature." Linnaeus's main collections are held by the Linnean Society of London, and other collections that he made throughout his lifetime are scattered at various institutions.

Classification of Organisms

Naturalists in eighteenth-century Europe were faced with a bewildering and ever-growing number of previously unencountered plants and animals, the result of European voyages of exploration. Many sought to develop some sort of natural classification system that would organize plants and animals according to the true relationships among things in the natural world. Such a system would necessarily be based on a complex assessment of numerous characteristics of the things being classified. This goal proved very difficult to attain, and some began to devise more artificial systems, sacrificing a broad focus on natural affinities for an easier-to-apply method using one or a few characteristics by which to sort and organize living organisms.

Linnaeus too saw the desirability of a natural system, and he published some basic principles for attaining one, but there were still not enough plants and animals known to allow for a sufficiently broad synthesis. Thus, for plants, he worked out an extremely simple system based on counting stamens and pistils , which provided an easy, practical, and usable means for sorting and identifying plants. The scheme was first published in Systema Naturae (1735), which contained tables in which the "three kingdoms of nature"—animal, vegetable, and mineral—were comprehensively classified.

For plants Linnaeus defined a genus (plural: genera) as a group of species with similar flowers and fruits. Genera were grouped into twenty-three classes of flowering plants by the number and disposition of stamens, with a twenty-fourth class for apparently nonflowering plants. Within classes they were arranged into smaller groups or orders according to the number and disposition of pistils. This scheme was called the "sexual system" because of its focus on the reproductive organs of plants. It was simple enough that even amateurs could use it to sort plants and ascertain whether they were already known to science.

The eighteenth century saw an information explosion in the natural sciences, and the utility and practicality of Linnaeus's classification scheme lay in the way it facilitated processing of information about the natural world. His sexual system of classification, although controversial and not widely accepted at first, was in general use in many countries for nearly a century, after which it was supplanted by more natural systems. Although it fell from use, in its time it reduced confusion in the study of organisms and facilitated the advancement of botany and zoology by providing a stopgap measure until a natural classification system could be developed.

Naming of Organisms

The nomenclatural system that Linnaeus developed in the process of classifying nature proved to be of greater and more lasting benefit to biological science. In the century before Linnaeus, plants and animals were given long, descriptive names (known as polynomials ) to differentiate them. For example, the polynomial name of catnip was "Nepeta floribus interrupte spicatus pendunculatis" (Nepeta with flowers in an interrupted pedunculated spike). There were no universally applied rules for constructing these names, however, resulting in considerable confusion in naming and referring to living things.

Linnaeus's solution to this problem, which was first applied to the plant world, was to group plants by genus and provide genus names (retaining many already in familiar use, or coining new ones), and then to give each species within a genus a "trivial" name, or what is known now as a specific epithet, so that each would have a unique two-part name, thereby unequivocally identifying that species. These trivial names, often in the form of Latin adjectives, were not necessarily descriptive, but they were linked to descriptive information, diagnoses, and references to previous descriptions in botanical literature. For example, he named catnip Nepeta cataria (cat-associated Nepeta). This enabled scientists to identify organisms with greater certainty, and provided a solid means for expanding and advancing knowledge. All in all, Linnaeus named approximately forty-four hundred species of animals and seventy-seven hundred species of plants.

The use of shorter names did not originate with Linnaeus. Folk names for plants and animals are typically short, and some scientists, notably Caspar Bauhin (1560-1624), used one- or two-word names when possible. However, pre-Linnaean names were often longer, using more adjectives in order to differentiate species within genera. Linnaeus was the first to construct a methodical and consistent nomenclatural system and to apply it to all living organisms then known to European science. His system was so comprehensive and so conducive to an integrated view of past and contemporary botanical studies that it won widespread acceptance and continues in current usage.

The nomenclatural system for plants was first published in his landmark work, Species Plantarum (1753). For animals, a similar system was published in the tenth edition of Systema Naturae (1758). These two works form the baseline for current nomenclatural practice in botany and zoology. Taxonomists in both disciplines still refer to Linnaeus's works when checking names of organisms, as mandated by international codes of nomenclature in both disciplines.

see also Herbaria; Taxonomist; Taxonomy; Taxonomy, History of.

Charlotte A. Tancin

Bibliography

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Dickinson, A. Carl Linnaeus: Pioneer of Modern Botany. New York: Franklin Watts, 1967.

Frangsmyr, Tore, ed. Linnaeus: The Man and His Work. Berkeley, CA: University of California Press, 1983.

Goerke, H. Linnaeus, tr. Denver Lindley. New York: Charles Scribner's Sons, 1973.

Gourlie, N. The Prince of Botanists: Carl Linnaeus. London: H. F. & G. Witherby Ltd., 1953.

Isely, Duane. One Hundred and One Botanists. Ames, IA: Iowa State University Press, 1994.

Kastner, Joseph. A Species of Eternity. New York: Alfred A. Knopf, 1977.

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Stafleu, Frans A. Linnaeus and the Linnaeans: The Spreading of Their Ideas in Systematic Botany, 1735-1789. Utrecht: A. Oosthoek's Uitgeversmaatschappij J.V. for the International Association for Plant Taxonomy, 1971.

Stearn, W. T. "The Background of Linnaeus's Contributions to the Nomenclature and Methods of Systematic Biology." Systematic Zoology 8, 1 (1959): 4-22.