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Classification

Flower sectionClassification was a complex and strange thing before Linnaeus developed his system, and became even stranger and more complex after.

Linnaeus was a great champion, and chief reviver, of Gaspard Bauhine's idea of giving all living things two names. Although the theory of binomial nomenclature had been around for almost one hundred years, it took Linnaeus to once again bring the idea forward and combine it with his unique system of sexual identification.

Although his system was designed to be simple, basing all flowering plant classification on the number of stamens in the bloom, and requiring the botanist to simply count them to determine which group the plant should be placed in, the complexity of nature was not so easily defined.

Through some translations, styles became wives, and stamens husbands, with their groupings being referred to as a marriage. This resulted in some very strange, and occasionally very funny, descriptions. Despite this peculiar result, in one form or another, Linnaeus' method was the standard for many years to come.

The core of his method was the binomial, or two name, method of classification that he championed, where all living things were given two basic latinized names to determine their relationship to all other living things. Gaspard Bauhine had first proposed this idea in his seminal work Pinax (1623) in which he described over 6000 plants and set out his basic criteria for classification, but it took over one hundred years before Carl Linnaeus resurected the idea.

By combining the binomial method with his (originally) simple method of counting stamens, Linnaeus created a working system of classification that became widely embraced, as it proved on the whole, to be much more practical and flexible than any previous method devised.

There have been a few other methods of classification since the days of Linnaeus, but it would seem that all will soon fall by the wayside, as DNA classification is likely to replace all previous methods. However, the binomial system of applying names will nonetheless remain.

The Binomial Name

While the full name of a plant, if you include Kingdom, Phylum and Family, might seem long enough to put most European royalty to shame, the real core of the plant's name is its 'binomial' name. 'Binomial' literally means 'two names' and refers to the two core names, which are Genus and species.

The following is the very Royal sounding full name of the common sunflower, with a breakdown of what the various names represent.

  • Plantae Tracheobionta Spermatophyta Angiospermae Eudicotyledon Asteridae Asterales Asteraceae Helianthus annuus L. - Common Annual Sunflower
  • Kingdom = Plantae
    The Plant Kingdom. There are several Kingdoms of life, with 'Plants' and 'Animals' being the best known. (Although often mistaken for plants, seaweeds are not plants at all, but belong to the Kingdom 'Protoctistae', and mushrooms, also often mistaken for plants, belong to the Kingdom 'Fungi'.)
  • Subkingdom = Tracheobionta
    Vascular plants. Plants with a vascular system, a system of veins for transporting nutrients throughout the organism. This allows some plants to grow very tall, since they can fight gravity and move nutrients and water heights in excess of 100m (350 feet). Try carrying a bucket of water up the stairs of a 35 storey building to get an idea of what an incredible effort this actually is. Plants without a vascular system are usually very small and almost never exceed a 2cm (1 inch) in hieght. Good examples of a nonvascular plants are the Liverworts and mosses.
  • Superdivision = Spermatophyta
    Seed plants. Seeds have the great advantage of carrying with them all the genetic information they need to make a new plant, and they even carry a small food supply to help them get started. Ferns and mosses are actually quite primative and reproduce using spores, not seeds. (Individual spores do not carry a complete set of genes. Two spores of the same species must meet together in perfect conditions to combine and grow into a new organism.)
    Seed plants are divided into two main groups
    1. Gymnospermae - The naked seeded plants include conifers (pines, cedars, fir trees etc.), cycads (ancient plants that look a little like palm trees with pine cones),and Welswitchia, an enigmatic and strange plant from the Namib desert in Africa.
    2. Angiospermae - The flowering plants
  • Division = Angiospermae (Magnoliophyta)
    Flowering plants. For a long time it was believed that Magnolias were the original flowering plants, but new fosil records suggest that there were much earlier, and far more primative flowering plants before them.
    Flowering plants are devided into six main groups,
    1. Amborellaceae - Amborella trichopoda is the only surviving member of this group. It is a small shrub with tiny greenish-yellow flowers and small red fruit, and is native only on the island of New Caledonia in the South Pacific. A rare plant with only a very few specimens in cultivation.
    2. Nymphaeaceae - Waterlilies, which are now considered to be among the most primitive of plants.
    3. Illiciaceae - Star anise
    4. Magnoliids - The Magnolias, and other ancient flowering plants such as 'Duchman's Pipe' - Aristolchia sp.
    5. Monocotyledons - palms, grasses, lilies, orchids etc.
    6. Eudicots - Until recently, all flowering plants that were not Monocotyledons were classified as Dicotyledons. These names describe how the plants start life as they sprout from seed. Monocots will always produce a single seed leaf, while Dicots will usually produce two seed leaves - although they may occasionally produce three or more as the result of a genetic anomaly. Dicotyledon means 'two seed leaves' but since DNA studies have revealed a more complex set of plant groups, the name Eudicotyledon was given to all flowering plants not included in the previous five groups.
  • Subclass = Asteridae
  • Order = Asterales
  • Family = Asteraceae
  • Genus = Helianthus
    A Genus is a group of related species of plants. In this case the Genus is Helianthus, the Sunflower, which contains approximately 70 species. This number is subject to change from year to year, as new species are discovered and/or old species are combined. Combining, or 'Lumping' happens when, after much botanical debate, it is decided that two different species aren't really different enough to justify being called seperate, so instead they are lumped into a single species. Sometimes the opposite happens when a species is devided because two subspecies are considered to be different enough to actually be classified as separate species. If you've heard about the 'Lumpers' and the'Splitters' arguing about how to classify plants, then this is a small example of what the arguments are about. Classification is a living science, and like the organisms it studies, it must change and adapt over time.
  • Species = annuus
    In this case the name just means 'Annual'.
    While all these names help to organize this species' place in the whole system, it is the Binomial Name that is most often used. The unique binomial name for the Common Annual Sunflower is 'Helianthus annuus', which translates from the Latin to 'Sunflower, annual'. Not all scientific names translate into the common name as neatly as that, though.
  • L - this 'L' refes to the botanist who scientifically described the plant, in this case, none other than Carl Linnaeus himself, the 'Champion' of the Binomial System.

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