On a category of genus in the 18th century botany: Linnaeus and his opponents
Authors: Sytin A.K. 
Published: October 2022

The period of 1737 through 1739 was exceedingly important in the life of Linnaeus in Holland where he published his well-known «Genera Plantarum» (1737). This work is of importance in modern taxonomy as a source of descriptions of 935 genera (in all a total of 1336 Linnaeus’ genera of plants were diagnosed). Basically the Linnaean concept of the genus was in accord with the French botanist J.P. Tournefort that the fundamental category of classification was the genus, and that plants having in common two or three characters of reproductive structures were usually to be treated as members of the same genus. Linnaeus so– called sexual system «of plant classification» comprised 24 classes, 23 of which contain the flowering plants, with stamens and pistils was highly artificial was expanded and served as the basis for «Genera plantarum». At the same time Linnaeus preparing the manuscript for a sumptuous work «Hortus Cliffortianus» (1737), in which were named and described many temperate and tropical plan grown in the botanical garden by George Clifford, Director of the Dutch East India Company. The genus Сliffortia was selected to honour of the owner of plant collection. The Genera of Linnaeus were based largely on the belief that a genus is a category whose components (species) have the essential character, it discriminated between species to morphological distinctions of leaf forms: С. ilicifolia, C. polygonifolia, С. ruscifolia, С. trifoliata; discriminated through stem habit types: Phascum acaulon, P. caulescens, P. repens; geography and its relationship to plant distribution: Parietaria cretica, P. lusitanica, P. zeylanica – in a literal sense is illustrated Linnaeus’ metaphora: «plantae omnes utrinque affinitatem monstrant, uti Territorium in Mappa geograpica» («Philosophia botanica » (PhB) Systemata. II. 77). It is evident that according to Linnaeus’ concept of the genus the naming of plants must be reflected a significant selected characters(«Nomen specificum legitimum plantam ab omnibus congeneribus distinguat”(PhB) Differentia. VIII. 257). It is likely that the Linnaeus’ metod integrated an elements of system, was elucidated the structure of a genus as a natural and phyletic unit. Therefore this concept provides the basic for modern plant classification and flowering plant phylogeny. However, a few years later Peter Simon Pallas (1741–1811), a professor of St. Petersburg Academy of Sciences in his taxonomical works recognized several species in the genus Polycnemum (now partly Petrosimonia Bunge; Chenopodiaceae). Perhaps engage in controversy against Linnaeus’s study and pursue polemical goals he named plants with according to number of stamens: P. monandrum Pall. – with only one stamen in androecium; P. triandrum Pall. – with three stamens. It was a corrective action on the advancement of the method of natural classification and, on opposite sides, a parody on the Linnaeus’s artificial classification. A delimitation of taxonomical content of a genus as a natural units – the second most important problem by most contemporary scientist , but on this point the Linnaeus’s authority was incontestable for Pallas. He even renounced one’s point of view on the name of Rindera Pall., in consequence of Linnaeus’s critical opinion and this plant name unwillingly accepted as Cynoglossum L. in his «Flora Rossica» (1788, 1, 2 : 97). Only in last works as a first monograph of genus Astragalus «Species astragalorum descriptae et iconibus coloratis illustratae» (1800–1803), Pallas used as the basic personal method and recognized into the genus six almost natural groups («Astragalorum phalanges»). It was an important precondition to positioned approach of biological classification in botany, that «the true beginning and end of botany is the natural system» (PhB. Systemata. II. 77).