Plant Classification during Different Periods

The below mentioned article provides an overview on  History of Plant Classification during Different Periods.

Preliterate Humans:

Ancient men who made their living by gathering food from the landscape, knew many plants by necessity and are considered to be practical plant taxonomists. They described and classified a plant as useful or harmful, so that others could recognize it, and identified other plants belonging to a particular category and assigned a name to the category, so that, it could be easily referred to.

Since this is pre-written record, we have little direct knowledge of this period. However, there are much archaeological evidence and even information from ancient paintings, drawings or utensils and virtually all civilizations have taken advantage of the medicinal properties of plants, the closely guarded secrets of which were passed on from medicine man to medicine man.

Even today, we can learn a lot about plants from the so-called “primitive” cultures. For example, present day indigenous people such as the brujos in the American tropics can recognize thousands of plants, which they use for food or medicine, having their own names, and we can learn a lot from them.

Ancient Greeks:

One of the first documented efforts to systematize a local flora was that of Theophrastus. Theophrastus and Dioscorides are considered to be the main contributors among the ancient Greeks.

(i) Theophrastus (370-285 B.C.) who was a student of Plato and Aristotle, and later became chief of the Lyceum (gardens and library) in Athens, is often called the “Father of Botany“. He named about 480 species in his famous works Enquiry into Plants and The Causes of Plants (both translated in English).

He classified plants by form into trees, shrubs, undershrub’s and herbs. He also recognized annuals, biennials, perennials and floral morphology such as superior and inferior ovaries, gross anatomy i.e., whether the calyx and corolla are modified leaves, free and sympetalous corollas, etc.

He noted the distinction between different kinds of tissues and between flowering plants (Phanerogams) and non flowering plants (Cryptogams). A few generic names currently in use such as Asparagus, Crataegus, Daucus (carrot) and Narcissus (daffodil) originated during this time.

(ii) Pedanios Dioscorides (62-128 AD.) was a Greek physician in the Roman Army. His most famous work was Materia Medica, in which he described the medicinal qualities of 600 kinds of plants. Many members of currently recognized families were classified together such as mints and umbels i.e., he grouped plants together with at least a superficial degree of natural relationships.

Middle Ages:

There was little original science or observations between the fall of the Roman Empire and the renaissance. Intellectual stagnation of the middle ages resulted in the minimal original work in plant systematics. the Ancients were thought to have possessed all knowledge, and their works were copied repeatedly.

One of the taxonomists during this period named Albertus Magnus (1193-1280) in his work De Vegetabilis, recognized monocots and dicots and divided the dicots into vascular and nonvascular plants. 

Herbalists:

People during this period, sought originality, and studied plants and not just accepted and copied what the ancients said. This period of renaissance was marked by extensive exploration and learning and with the invention and implementation of the printing press (1440), many large volumes, about plants and their uses, known as herbals, were produced throughout Europe for use, particularly by the physicians.

Many natural and well-defined genera and families were established during this period and for the first time in history, the key characteristics of plants were depicted via woodcut or metal plate engravings.

Some of the well-known herbalists and their famous works during this period include:

(i) Otto Brunfels (1464-1534) – Herbarium Vivae Eicones

(ii) Jerome Bock (1469-1554) – Neu Kreuterbuch

(iii) Leonhart Fuchs (1501-1566) – De historia stirpium

(iv) John Gerard (1542-612) – The Herball, or, Generall Historie of Plantes

(v) Rembert Dodoens (1517-1585) – Cruydeboeck

(vi) Casper Bauhin (1560-1631) – Pinax theatri botanici.

The Pre-Linnaean Period:

(i) Andrea Caesalpino (1519-1603):

He is considered to be the first plant taxonomist as he was the first botanist to try to base a taxonomic scheme upon reason and logic rather than purely on utilitarian concepts. His most famous work is De plantis Libri, in which he named 1520 plants.

His classification system used an Aristotelian approach, which is based upon habit (trees, shrubs, herbs), but it also used a whole series of floral, fruit, and seed characters. It recognized what today we know as the mustard, aster, carrot, and herbaceous and woody legume families.

(ii) Joseph Pitton de Tournefort (1656-1708):

His most famous work is Institutiones Rei Herbariae. He is the first in a series of important French botanists and his artificial system of classification for 10,146 plants includes 698 genera. He is the first to give a real concept of genera.

He divided flowering plants into 2 large categories, trees and herbs, which were further subdivided into groups on the basis of characters such as petalous or apetalous, regular or irregular and polypetalous or gamopetalous.

(iii) John Ray (1628-1705):

He was a British botanist and his most famous work is Synopsis Methodica Stirpium Britannicarum, which is the first British flora. He also published Methodus Plantarum Nova in 1682 and Historia Plantarum (1696-1704). His natural system of classification in which he grouped together plants that looked alike, was complicated, as it used many different characters and split natural groups and lumped together unnatural ones.

He believed in “essential” characters. The last edition of Methodicum treated 18,000 species, and the main divisions were woody and herbaceous plants and he recognized the taxa of monocots and dicots, the classes were based on fruit type and the subdivisions on the basis of leaf and flower characters.

The Linnaean Period:

By the middle of the 18^th century, further developments in science, advances in navigation, early microscopes, widespread travel, use of herbarium specimens, widely available printed books, ground work of herbalist, made the science of botany ready for a person to synthesize information.

(i) Carl von Linne or Carolus Linnaeus (Latinized form of his name) [1707-1778]:

He was a Swedish and his famous work included Systema Naturae. His classification system is called artificial, as it relied upon a few features of the flower (mainly the number of stamens and pistils) as the primary basis for division. His system was correct in some cases, but not in others, as he put clearly unrelated plants together.

He developed the sexual system of classification and called it Nuptiae Plantarum (marriages of plants). Written in metaphorical terms in Systema Naturae is “husband and wife have same bed,” or “five husbands in the same marriage,” etc. referring to the arrangement of stamens and carpels in the flower.

He named 12,000 species (7,700 plants, 4,300 animals) and 1,105 genera. His other important works include, Genera Plantarum and Species Plantarum. The latter, which was published in May, 1753, is the starting point for botanical nomenclature. Species names are given in the margin and descriptions were like the old polynomials.

Linnaeus is most known today for the following reasons:

a. He popularized a system of nomenclature now called the Binomial System, which replaced the polynomials used in his original work, by a “shorthand” way of referring to the plant by two names – a generic name and a specific epithet.

b. His works included brief diagnoses (short descriptions) of the plants.

c. He standardized the synonymy (duplicate names) of many plants.

d. He developed a number of terms used in plant morphology.

Post-Linnaean Period:

The French never really adopted the system of Linnaeus, and based on their experience in the botanical gardens of Paris (Jardin de Botanique de Paris), they soon developed their own, first natural system of classification.

Some leading botanists of that time were:

(i) Michel Adanson (1727-1806):

He is considered as the ‘Grandfather of Numerical Taxonomy’. His famous work is Families des Planters. He rejected artificial classification and developed ways to logically deal with large number of characters and his methodology foreshadowed numerical taxonomy (phenetics).

He felt that using as many characters as possible, would give the most natural and useful classification. His system is often called Adansonian Taxonomy.

(ii) Antoine Laurent de Jussieu (1748-1836):

His work Genera Plantarum led to a Natural Classification System, based on common sense. He divided the flowering plants into 15 classes, which were further subdivided into 100 natural orders corresponding to most major families, each of which was clearly differentiated, named and provided with a description.

Many of the families recognized then are still recognized today. Botanists of the time readily accepted this system over that of Linnaeus, as the plants which looked alike were grouped together.

(iii) Jean Baptist de Lamarck (1744-1829):

His work includes Flore Frangoise. He is best known for an early theory of evolution by inheritance of acquired traits. He used identification keys similar to dichotomous keys of today.

(iv) Augustine Pyramus de Candolle (1778-1841):

His work Prodromus Systematis and Naturalis Regni Vegetabilis was an attempt to do a world flora, which was never finished. It included 58,000 species and 161 families. It depicted the catkin-bearing dicots (e.g. Betulaceae, Fagaceae, etc.) as being related to gymnosperms and his system of classification began the dicots with Ranunculaceae.