Today, experienced gardeners and landscapers use binomial names to ensure that they are planting the best species for a particular location or use. A binomial name--also knows as a scientific or Latin name--is unique to a particular species and describes its relationship to other organisms, allowing experts to identify, understand and communicate about a particular plant, and is part of the modern science of taxonomy. Classifying plants, however, began in prehistoric times, when people learned to identify plants based on their use as medicine or food.
Classification of plants began with a very practical purpose in mind: determining what was good to eat and what would kill you if you ate it. Early cultures likely identified and classified plants based on their uses, such as whether they were edible, useful as medicines or could be used as weapons or for other purposes. Many foods and medicines that we use today originate from cultures that had been using these plants for thousands of years.
The Western science of taxonomy, the classification of living organisms, began in ancient Greece. Although numerous writers were interested in naturalism, including classification, Aristotle's work, in particular, influenced how we classify plants today. Aristotle envisioned all species organized in what he termed a "Great Chain" that placed species in a hierarchy according to complexity. All links on the chain must be occupied by a species, and no two species could occupy a single link.
From Aristotle's ideas, we got the idea that persists even into modern thought that some species are higher or lower than others, suggesting that they are more advanced in their adaptations.
Aristotle's ideas would remain relatively unchallenged for more than 1,000 years, until the work of Swedish physician Carolus Linnaeus. Linneaus' passion was for botany and classification, and he developed the taxonomic system we use today. Rather than attempting to sort plants hierarchically as higher or lower, based on Aristotelian principles, Linnaeus classified them according to their relationships, developing a system that, when visualized, resembles a tree with many branches rather than a single line. Binomial names originated with Linnaeus--many still in use today--as did the practice of classifying plants primarily based on reproductive structures, such as seeds and flowers.
Modern taxonomy uses Linnaeus' system, identifying species using progressively narrower classifications until reaching the species level. Species that share more classifications are more closely related. For example, the Plant Kingdom includes all plants, so all plants from simple mosses to oak trees to wild roses are classified here. As classification progresses, plants that are less related are separated into new classifications.
Taxonomy is not an absolute science and blends many disciplines, such as molecular biology, morphology, evolutionary biology and cytology. With such a wealth of information available, some of it leading to different classifications of the same species, taxonomists often disagree on how information should be used and sometimes have different answers to fundamental questions. As these questions are resolved, the next chapter in the history of classifying plants will unfold.