Swedish naturalist known as the father of modern botanical and zoological taxonomy. Carl Linnaeus, Professor of Botany and Medicine at Uppsala University, was the first to consistently apply the binomial system used universally in biological nomenclature today. He also devised a method of classifying plants based on their sexual characteristics, although this is no longer in use. His publications Systemae Naturae and Species Plantarum are considered his major works and have had a lasting impact on natural history.

Before Linnaeus' innovations, plants (and animals) were given long names of several Latin words and synonyms were rife. Linnaeus simplified these to a genus name and a species name, namely the binomial system still in use today. Linnaeus' sexual system, meanwhile, uses the number and arrangement of flower stamens and pistils to group plants into 24 classes, which are then divided into orders, genera and species, and is no longer consistently applied.

Born to a Lutheran pastor on 23 May 1707 at Råshult, in the southern Swedish province of Småland, Carl Linnaeus showed an early interest in plants and their names. Rather aptly, his grandfather had taken their family name from the local word for the lime tree, linn. The young Linnaeus was introduced to the study of botany by a local physician, Johan Stensson Rothman (1684-1763), and his fascination with the sexual parts of plants developed at this time. He entered the University of Lund in 1727, studying medicine, and maintained a strong interest in botany, often consulting the natural history collections and library of Dr Kilian Stobaeus, who gave the student free bed and board.

Linnaeus was unimpressed with the quality of the teaching at Lund and transferred to Uppsala University in 1728, where he found things no better, for there were not enough funds to maintain the university hospital and the botanic garden was poorly stocked. Surprisingly, Linnaeus was never privy to a single lecture on botany during his student years in Sweden. At Uppsala he found another friend in the form of theologian and naturalist Olof Celsius the Elder (1670-1756). Linnaeus moved into the home of Celsius (uncle of the inventor of the Celsius temperature scale), where he could use his library and help Celsius with his flora of Uppland. By this time, Linnaeus had amassed a herbarium of hundreds of Swedish plants and in 1730 showed Celsius the work that would serve as his dissertation in 1746, describing the sexual lives of plants. Titled Praeludia Sponsalia Plantarum, it was inspired by the observations of Sébastien Vaillant. Linnaeus was thereafter employed as a demonstrator in the botanic garden at Uppsala, marking the beginning of his teaching career.

At Uppsala Linnaeus also formed an academic partnership with medical student Peter Ardeti. They decided to study and document the natural world together, working out a system of diagnosis, description and naming. Primarily concerned with plants, Linnaeus was not happy with the widely used classification system of J.P. Tournefort and decided at this time to invent his own, based on the stamens and stigmas of flowers. Only in his early twenties, he was already laying the foundations of his later major works.

In 1732, Linnaeus decided to explore Lapland. His interest in the region was sparked by travels made there by his teacher, Olof Rudbeck the Younger, whose collections made there had been destroyed by fire 30 years before. Linnaeus went alone, on horseback, in May that year, collecting plants, animals and minerals and noting down observations of the people he encountered. He stopped at Umeå, Jokkmokk and Rörstad, returning via Torneå, Vittangi and Tuurku. It was on this journey he discovered the plant that would be named after himself, Linnea borealis L. (coined by J.F. Gronovius but formally published by Linnaeus) and recorded observations on the pearl fishery near Jokkmokk. Linnaeus' collections led to the publication of his Flora Lapponica (1737), but his journal from this time was only published for the first time posthumously, in 1811 (in English).

Linnaeus' next fruitful alliance was with student Claes Sohlberg, whose father was a mining inspector. The pair spent Christmas 1732 in the copper mining town of Falun, Dalecarlia (now Dalarna), and in 1734 Linnaeus and Sohlberg worked with a team to survey the province, commissioned by the regional governor. Linnaeus had little desire to then return to Uppsala and gladly accepted an invitation to join Sohlberg in travelling to the Netherlands in 1735. The pair left from Helsingborg on 18 April 1735 and reached Amsterdam in late May, having stopped in Hamburg for three weeks. In Amsterdam they met the director of the Botanic Garden and professor of botany, Johannes Burman, and the apothecary Albert Seba. They travelled on to Harderwijk, where the accommodating university granted Linnaeus a Doctor of Medicine degree for his thesis on the cause of intermittent fevers.

Linnaeus' sojourn in the Netherlands turned out to be a significant period in his development. He impressed the physician and botanist Jan Gronovius with his manuscript, Systema Naturae, and Gronovius subsequently had it published at his own expense. The volume provided a concise survey of all the world's plants and animals then known. Successful, it went through many more editions after the first, which appeared in 1735. Gronovius also introduced Linnaeus to the esteemed Leiden botanist and physician Herman Boerhaave, who invited the young Swede to his estate at Oude-Poelgeest.

Returning to Amsterdam he began assisting Burman with his Ceylon flora, Thesaurus Zeylanicus (1737). It was not long before Linnaeus took up another offer, however, and moved to the country estate of banker George Clifford. At the Hartekamp, near Haarlem, Linnaeus served as physician to the Anglo-Dutch Clifford, meanwhile acting as caretaker to Clifford's gardens and glasshouses, with their huge range of plants including a banana which he helped to coax into flower. In addition Linnaeus used his time at the Hartekamp to complete his works Fundamenta Botanica (1736) and Bibliotheca botanica (1736), dedicating this latter tome to Burman. Following the accidental death by drowning of his university friend Artedi, he also edited and published his friend's book, Ichthyologia (1738), with the help of Clifford.

It was not only Linnaeus who benefited from Clifford's benefaction. The famous drawing illustrating Linnaeus' Sexual System by George Dionysius Ehret was produced at the Hartekamp, after Clifford commissioned the artist to produce plates for his Hortus Cliffortianus.

In 1736 Linnaeus briefly left the Netherlands and visited England, where he met Sir Hans Sloane, Philip Miller, Peter Collinson and John Martyn in London. He was impressed with the volumes of Sloane's natural history collections, but not their organisation. He also met Johann Jakob Dillenius and Thomas Shaw in Oxford, before returning to Clifford in August with plants from Chelsea Physic Garden and dried specimens from Mexico, given to him by Miller. At this point he began work on a catalogue of plants at the Hartekamp, Hortus Cliffortianus, illustrated by Ehret. It was published in 1737, in which year Linnaeus' Genera Plantarum, Flora Lapponica and Critica Botanica also came out.

The winter of 1737 found Linnaeus in Leiden, working with the Botanic Garden director Adriaan van Royen on a new arrangement of the garden's plants. He also collaborated with Gronovius again, who was working on his Flora Virginica. In 1738 he travelled again, meeting Bernard and Antoine de Jussieu in Paris and also visiting Fontainebleu.

Linnaeus returned to Sweden from France in July 1737, at first going back to Falun, then settling in Stockholm as a physician. He made a lasting tribute to the people he had met on his travels with plant names including Cliffortia, Gronovia and Milleria, but in Sweden Linnaeus' ideas and new plant names were not welcomed. Nevertheless he did well as a physician, being given a royal appointment, and was the first president of a new Academy of Sciences. He also married, and in 1741 took up the post of Professor of Medicine and Botany at Uppsala. In this period he carried out a survey of two islands in the Baltic for the government, paying particular attention to whether the islands could supply clay for making porcelain and plants for dyes. The account of the expedition, undertaken with a team of students, appeared in 1745.

In Uppsala Linnaeus took responsibility for renovating the botanic garden, including building an orangery. He employed George Clifford's head gardener, Dietrich Nietzel, and by 1748 had increased ten-fold the number of plants cultivated there since a decade prior, as well as bringing in peacocks, parrots and monkeys. He was by now receiving all sorts of interesting collections of dried plants, and published an account of the native plants of his home country, Flora Suecica, in 1745. The following year he made another exploratory tour of the country, his primary destination being Västergötland. On this trip he met Nicolaus Sahlgren, director of the Swedish East India Company, in Gothenburg, and acquired new zoological and mineralogical specimens from him.

Back in Uppsala, Linnaeus began work on what was to become Species Plantarum (1753), cataloguing the distinguishing features of all known plant species. To produce this oeuvre he consulted the many collections he had been sent by contacts, representing flora from Russia to Sri Lanka, America and China. He was especially enthused by the hundreds of new plants from North America, brought to him by his student Pehr Kalm, and the work also contains new species presented by another Linnean student, Pehr Osbeck, following his return from China.

In 1749 Linnaeus undertook a survey of the southwestern province of Skåne on behalf of the king, assisted by a student, Olof Söderberg. The next year was taken up with preparing Skånska Resa and Philosophia Botanica (both 1751), before he set to work once more on Species Plantarum, published in May 1753 and dedicated to the King and Queen of Sweden. The two volumes (the second of which was actually published in August) contained accounts for 5,900 plant species, crucially giving just a single specific epithet in the margin of each entry. A fifth edition of Linnaeus' Genera plantarum appeared in 1754. Many botanists followed Linnaeus and adopted the binomial system in the next few years, including Johannes Burman and Nicholas Jacquin, while others such as Philip Miller were pleased to arrange their works along the lines of his sexual system, but retaining polynomials.

The remainder of the 1750s continued to offer up more and more collections from around the world for Linnaeus to study, such as Patrick Browne's from Jamaica and Mediterranean specimens from Mårtin Kähler. He was created a Knight of the Polar Star in 1758 and at this time settled on an estate at Hammarby, outside Uppsala, where he planted a garden full of exotic species. The estate was paid for with the proceeds from a patent Linnaeus had taken out on a technique of seeding mussels to produce pearls. Enobled in 1760, he took the name von Linné.

Linnaeus introduced standardised binomials for animals in the 10th edition of his Systema Naturae (1758), the second volume of which contained all the plants from Species Plantarum and all the new ones he had described since then. This standardised nomenclature is still in use today. Three years later he brought out a second edition of Species Plantarum and in 1767 a new edition of the botanical volume of Systema Naturae, accompanied by an appendix, Mantissa Plantarum. His last substantial botanical works were Mantissa Plantarum Altera (1771) and Plantae Surinamenses (1775), the latter based on collections by Carl Dahlberg.

A great fire ripped through Uppsala in 1766. Linnaeus' collections were saved, but the next year he had a special building constructed at Hammarby for the safekeeping of his herbarium. Unfortunately, having no fireplace, it was a cold and damp place, not ideal for the preservation of dried specimens. Plants were continuously being sent to him from as far away as South Africa and South America, but by 1772 Linnaeus' health was beginning to fail. He finally succumbed to a series of strokes and died on 10 January 1778, aged 70. He was buried in Uppsala Cathedral. Linnaeus' botanical and zoological collections and library passed to his wife on his death, but with a harsh declaration that his son should not be allowed to consult them. After failing to secure a sale for the collections Linnaeus' wife allowed her son to remove them to Uppsala. On the death of the younger Linnaeus in 1783, efforts were made once again to sell the collections. They were initially offered to Joseph Banks but ultimately bought by James Edward Smith on Banks' recommendation. They ultimately formed the basis of the Linnean Society of London, founded in 1788, although they remained the property of Smith until his death in 1828, at which point the Society had to purchase them from Smith' estate.

Sources:
W. Blunt, 2001, The Compleat Naturalist: A Life of Linnaeus
B.D. Jackson, 1923, Linnaeus (adapted from the Swedish of T.M. Fries)
C. Jarvis, 2007, Order out of Chaos: 63-80
The Linnean Society:
http://www.linnean.org/index.php?id=51, accessed18 November 2011.