Linnaean taxonomy

The title page of Systema Naturae, Leiden (1735)

Linnaean taxonomy can mean either of two related concepts:

  1. the particular form of biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his Systema Naturae (1735) and subsequent works. In the taxonomy of Linnaeus there are three kingdoms, divided into classes, and they, in turn, into orders, genera (singular: genus), and species (singular: species), with an additional rank lower than species.
  2. a term for rank-based classification of organisms, in general. That is, taxonomy in the traditional sense of the word: rank-based scientific classification. This term is especially used as opposed to cladistic systematics, which groups organisms into clades. It is attributed to Linnaeus, although he neither invented the concept of ranked classification (it goes back to Plato and Aristotle) nor gave it its present form. In fact, it does not have an exact present form, as "Linnaean taxonomy" as such does not really exist: it is a collective (abstracting) term for what actually are several separate fields, which use similar approaches.

Linnaean name also has two meanings: depending on the context, it may either refer to a formal name given by Linnaeus (personally), such as Giraffa camelopardalis Linnaeus, 1758, or a formal name in the accepted nomenclature (as opposed to a modernistic clade name).

The taxonomy of Linnaeus

In his Imperium Naturae, Linnaeus established three kingdoms, namely Regnum Animale, Regnum Vegetabile and Regnum Lapideum. This approach, the Animal, Vegetable and Mineral Kingdoms, survives today in the popular mind, notably in the form of the parlour game question: "Is it animal, vegetable or mineral?". The work of Linnaeus had a huge impact on science; it was indispensable as a foundation for biological nomenclature, now regulated by the nomenclature codes. Two of his works, the first edition of the Species Plantarum (1753) for plants and the tenth edition of the Systema Naturae (1758), are accepted as part of the starting points of nomenclature; his binomials (names for species) and generic names take priority over those of others. However, the impact he had on science was not because of the value of his taxonomy.

Classification for plants

His classes and orders of plants, according to his Systema Sexuale, were never intended to represent natural groups (as opposed to his ordines naturales in his Philosophia Botanica) but only for use in identification. They were used for that purpose well into the nineteenth century.[1] Within each class were several orders.

Key to the Sexual System (from the 10th, 1758, edition of the Systema Naturae)
Kalmia is classified according to Linnaeus' sexual system in class Decandria, order Monogyna, because it has 10 stamens and one pistil

The Linnaean classes for plants, in the Sexual System, were:

  • Classis 1. Monandria: flowers with 1 stamen
  • Classis 2. Diandria: flowers with 2 stamens
  • Classis 3. Triandria: flowers with 3 stamens
  • Classis 4. Tetrandria: flowers with 4 stamens
  • Classis 5. Pentandria: flowers with 5 stamens
  • Classis 6. Hexandria: flowers with 6 stamens
    • Hexandria monogynia pp. 285–352[2]
    • Hexandria polygynia pp. 342–343[3]
  • Classis 7. Heptandria: flowers with 7 stamens
  • Classis 8. Octandria: flowers with 8 stamens
  • Classis 9. Enneandria: flowers with 9 stamens
  • Classis 10. Decandria: flowers with 10 stamens
  • Classis 11. Dodecandria: flowers with 12 stamens
  • Classis 12. Icosandria: flowers with 20 (or more) stamens, perigynous
  • Classis 13. Polyandria: flowers with many stamens, inserted on the receptacle
  • Classis 14. Didynamia: flowers with 4 stamens, 2 long and 2 short
  • Classis 15. Tetradynamia: flowers with 6 stamens, 4 long and 2 short
  • Classis 16. Monadelphia; flowers with the anthers separate, but the filaments united, at least at the base
  • Classis 17. Diadelphia; flowers with the stamens united in two separate groups
  • Classis 18. Polyadelphia; flowers with the stamens united in several separate groups
  • Classis 19. Syngenesia; flowers with 5 stamens, the anthers united at their edges
  • Classis 20. Gynandria; flowers with the stamens united to the pistils
  • Classis 21. Monoecia: monoecious plants
  • Classis 22. Dioecia: dioecious plants
  • Classis 23. Polygamia: polygamodioecious plants
  • Classis 24. Cryptogamia: the "flowerless" plants, including ferns, fungi, algae, and bryophytes

The classes based on the number of stamens were then subdivided by the number of pistils, e.g. Hexandria monogynia with six stamens and one pistil.[4]

Index to genera p. 1201[5]

Classification for animals

The 1735 classification of animals

Only in the Animal Kingdom is the higher taxonomy of Linnaeus still more or less recognizable and some of these names are still in use, but usually not quite for the same groups. He divided the Animal Kingdom into six classes, in the tenth edition, of 1758, these were:

Classification for minerals

His taxonomy of minerals has long since dropped from use. In the tenth edition, 1758, of the Systema Naturae, the Linnaean classes were:

  • Classis 1. Petræ
  • Classis 2. Mineræ
  • Classis 3. Fossilia
  • Classis 4. Vitamentra
Other Languages