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J. P. de Tournefort (1656-1708) was a Frenchman who carried further Bauhin’s promotion of the rank of genus. He had a clear idea of genera, and many of these in his Institutiones Rei Herbariae (1700) were later adopted by Linnaeus and are still in use today. Tournefort’s system, which classified about 9 000 species into 698 genera and 22 classes, was largely artificial but extremely practical, and it remained ‘in force’ until superseded by that of Linnaeus, and even later in France where the Linnaean system was never f properly adopted.

Nevertheless, his ideas and expertise were in many ways inferior to those of his English contemporary, J. Ray (1627-1705), a naturalist who produced several important books on plant classification. Most important of these were

Methodus Plantarum Nova (1682, 2nd ed. 1703), Historia Plantarum (3 vols.,

1686, 1688, 1704), and Synopsis Methodica Stirpium Britannicarum (1690, 2nd ed. 1696, 3rd ed. 1724 by J. J. Dillenius). The last of these was effectively the first British Flora, and a fine reproduction of it with useful introductory and bibliographic material416 has been published by the Ray Society, a learned Society concerned with the publication of new and the reprinting of old books on British natural history. The second edition of Ray’s Methodus dealt with nearly 18 000 species in a complicated system of classification, utilizing a very large number of characters of the flower and vegetative parts, for Ray believed, as we do today, that all parts of the plant should be used in taxonomy. Ray did not develop the idea of binary nomenclature commenced by Bauhin; his species were characterized by phrase-names. His system was somewhat unmanageable, largely due to the great number of species which it attempted to deal with, but technically it was far superior to that of Linnaeus which was to follow 50 years later.

The great increase in the number of species in the books of Ray and his contemporaries was partly due to the recognition of smaller entities, particu­ larly among the lower plants (Ray, for instance, had a narrower species concept than Linnaeus), but largely the result of exploration in regions beyond Europe, so that annually a great many new species were reaching the European taxonomists. It is against this background of increasing diversity of flora and somewhat chaotic bibliographic documentation that Linnaeus’ orderly writings must be viewed.

Phase 4. Linnaeus and his apostles

More has been written about the Swede, Carl Linne (usually latinized as Carolus Linnaeus (1707-1778), than any other biologist except Charles Darwin, which may be taken as a measure of the impact of these two scientists on biology. Linnaeus was the founder of modern taxonomy, both of plants and of animals, and the system of nomenclature which we employ today is essentially his. No attempt is made here to sketch even the outlines of Linnaeus’ life, philosophy or writings. Good insight into these (and leads to many of the works on the subject) can be gained by reference to three publications: Steam ’s introduction to the Ray Society’s facsimile of the first edition of Linnaeus’ Species Plantarum?15 Stafleu’s Linnaeus and the

Linnaeans, 413 and Blunt’s The Compleat Naturalist; a Life o f Carl Linnaeus?0

22 The dewlopnwnt of plant taxonomy

bewildering umiy of literatiirc, systems of classification and plants which confronted the eighteenth century botanist. He was a prodigious writer and produced many works of great value, which amply illustrate his talent for accurate observation, methodical recording, concise and clear summarizing and energetic enthusiasm.

For plant taxonomists the two most important works are Genera Plantarum (1737, with later editions) and Species Plantarum (1753, with later editions). In both of these works Linnaeus classified plants according to his artificial ‘Sexual System5 (Fig. 2.3), an outline of which is given in Chapter 1. This system was first published in 1735 in Systema Naturae, a work which classified all known animals and minerals as well as plants. The Genera Plantarum listed and briefly described the plant genera recognized by Linnaeus, and hence carried forward the work of Bauhin and Tournefort in giving promin­ ence to the rank of genus. Indeed, many of Linnaeus’ generic names came from the works of these two authors, while the new ones were often descriptives or were taken from classical literature or commemorated the names of distinguished botanists, for example Theophrasta, Dioscorea,

Fuchsia, Lobelia, Bauhinia, Rajania and even Linnaea. About ten editions of Genera Plantarum appeared, not all of which were prepared by Linnaeus

(several appeared after his death). Taxonomically the most important is the fifth edition (1754), which was very much the work of Linnaeus and was seen by him (and is recognized still by the International Code o f Botanical

Nomenclature) as an adjunct to the two volumes of the first edition of his Species Plantarum (1753). Together these two works, both published in

Stockholm, cover about 7 700 species in 1105 genera.

The Species Plantarum does not provide generic descriptions (cf. Genera

Plantarum), but under each genus it numbers, names and briefly describes the

various species (Fig. 2.4). References to important earlier literature which also recognized the species are given, together with the synonyms (where applicable), habitats and countries of origin. The description of each species is in the form of a phrase-name of up to twelve words, commencing with the generic name. The phrase-names were not all new; many were taken from previous works of Linnaeus and others. For new species (i.e. with no synonyms or earlier references), and some little-known others, the entry is concluded by a longer descriptive paragraph; genera with only one species usually were given no description at all for that species, since the generic description (in Genera Plantarum, 5th ed.) could equally do for the species.

In addition to the phrase-name, each species was provided (in the margin) with a one-word trivial name or specific epithet. As demonstrated by several researchers, these names ‘originated as an indexer’s paper-saving device’,415 but their use proved of such convenience that they quite quickly became the standard name of each species. The specific epithet variously did or did not repeat a key word from the phrase-name. Such a binary name, formed of the generic name plus the specific epithet, is known as a binomial, as distinct from the phrase-name which is a polynomial. Binomials were quite often used by G. Bauhin in his Pinax (1623) over a century earlier, so it is not true to say that Linnaeus devised the system. However, it was their appearance as an additional, convenient name for every species in Species Plantarum which led to their eventual universal adoption, and nowadays they are mandatory.

Phase 4. Linnaeus and his apostles 23