A Quick History of Plant Classification

By Chy and Ray Allen, Founders of AmericanMeadows.com

Beyond the local charm of common names, as official parts of the plant world, wildflowers are precisely classified. It’s all in order to make sense and keep track of the widely diverse group of plants involved. It sometimes seems complicated, but it really isn’t. A basic understanding of classification is really helpful to gardeners or even interested observers of the plant world.

The naming system used in scientific classification is known as taxonomy and plant taxonomy is divided into four essential components:

Description - Using words and pictures to describe plants
Classification - Simply putting plants into broad categories.
Identification - Process of putting described plant units into classes.
Naming - The systematic nomenclature that assigns a name to each plant.

Plant taxonomy today is the result of various advances made in plant classifications that began in ancient times. Each time an advance was made it was based on:

The needs of the historical period,
The level of knowledge that existed during each period, and
The philosophical concepts and technology available during the period.

How it All Began

Archaeological evidence supports the fact that preliterate humans knew plants out of necessity. They had to distinguish poison plants from non-poisonous plants, for example, in order to survive. So actually these earliest humans used all four parts of the taxonomy process:

They described certain plants so others could recognize them.
They classified plants, for example, poisonous vs. non-poisonous
They identified plants as belonging to one ‘family’ or category vs another,
They named plants and categories, so they could be properly referenced.

The Ancient Greeks

The earliest people of well-known civilizations to begin the process of plant classification were the ancient Greeks, and like most endeavors, there were important pioneers we know today by name:

Theophrastus (370-275B.C.E.) is foremost among the Greeks for plant study. He was a student of Aristotle and Plato who eventually became the head of the gardens at Athens. His most famous works are Enquiry into Plants and the Causes of Plants in which he named about 480 plant species classified into 4 groups: Trees, Shrubs, Undershrubs, and Herbs.

Theophrastus is the first credited with recognizing the differences among annuals, perennials and biennials. This early Greek botanist became so well known, that Alexander the Great is reputed to have sent him many plants from his travels.

Dioscorides (1st c. AD) was another Greek plant expert. He was a physician in the Roman army, so it’s not surprising that he was an early expert on medicinal plants. His most famous writing is called Materia Medica which described the medicinal properties of over 600 species. This ground-breaking work was used extensively for the next 1,000 years.

The Middle Ages

During medieval times, very little was added to the science of plant taxonomy since the ancients were largely considered to have possessed all such knowledge. However, there were advances. One of the most important was the recognition of vast differences between vascular and nonvascular plant forms.

The Herbalists

The 15^th and 16^th centuries are considered to be the prime time of the herbalists. It was a time of great belief in mystery, magic and superstitions, which naturally gave rise to curiosity and often wildly incorrect conclusions about the properties and values of certain plants. Medieval and Renaissance European herbalists identified approximately 6,000 plants, many of them brought for study from the many explorations of the period. Four famous herbalists and their major works are:

Otto Brunfels (1464-1534) Herbarum vivae Eicones
Jerome Bock (1469-1554) Neu Kretuerbuck
Leonhart Fuchs (1501-1566) De historia stirpium
Caspar Bauhin (1560-1631) Pinax theatric botanici

“Modern Science” arrives.

As superstition and magic subsided with the advance of education in Europe, various scholars began more modern studies of the plant world. Two important people who advanced the study are:

J. Ray (1628-1705) An Englishman who clearly drew the line between monocots and dicots.
J. P. Tournafort (1656-1708) A Frenchman who traveled widely throughout Europe and into Asia Minor and Africa, collecting and then introducing over 1300 new plants.

The person who organized it, once and for all: Linnaeus

The average person, if they know anything about taxonomy at all, probably knows this name. Linnaeus is deservedly known as “The Father of Plant Taxonomy.” It is his endlessly expandable system we all use today.

Linnaeus was born in southern Sweden in 1707, the son of a Swedish minister. It was his father who had taken the Latin name of Linnaeus in keeping with the fashion of the day for scholarly or important people to choose a classical name, or to “Latinize the patronymic.” He had chosen the name in honor of the linden or lime trees which graced the family homestead. Linnaeus’ real family name had been Ingermarsson. Beyond his Latinized name, Linnaeus was also known during his life as Carl von Linne’. But forget all that. To the plant world, he is Linnaeus.

By the time he was very young man, Linnaeus had distinguished himself as an authority in the natural sciences where he focused on the study of plants, animals, and minerals. Of the three, his greatest interest was in botany where he concentrated on not only identifying various plant species but also on their natural history and distribution.

While plant identification had been accumulating for centuries as we have seen, Linnaeus realized that the current knowledge lacked clearly defined systemization. There was no consistent plan of either arrangement or nomenclature.

The last attempts at combining the acquired knowledge of the past had been made by Ray in England and Tournefort in France, shortly before Linnaeus advanced his scheme. Ray and Tournefort had basically divided plants into trees and herbs along the lines of Theophrastus and then sub-divided them into groups that bore petals and those that did not and further sub-divided them yet according to the shape of the corolla. In the process Tournefort is given credit for establishing the “concept of genus” in his landmark work, Institutiones Rei Herbariae.

Linnaeus developed his system of classification based on a plant’s sexuality, organizing them into groups called Classes and Orders. These divisions are based on pistil and stamen structure. He wrote about this in two of his most important books: Genera Plantarum in 1737 and Species Plantarum in 1753.

In the Genera Linnaeus accepts and defines the genus according to Tournefort. In the Plantarum, he meticulously describes each species within its appropriate genus going on to further describe varieties within the species, all formulating the basis of his system of classification.