The following points highlight the five periods in the history of plant classification in India. The periods are: 1. Rig Veda Period 2. The Greek Period 3. The Roman Period 4. The Dark Age, Herbals and the Transition Period 5. Modern Period.
Period # 1. Rig Veda Period:
According to Majumdar history of botany and plant taxonomy in India can be traced back to the period of Rig Veda 3000 B.C. (and earlier) and later Hindu literature including Manu, Agnipurana, Vrikshayarveda etc. A broad classification of plants into trees, shrubs, herbs and creepers is to be found in the mantras (hymns) of Rig Veda.
Plants were further classified into those that produced fruits and flowers and those without fruits and flowers. Thus as early as 3000 B.C. we come across a classification approaching Phanerogamia and Cryptogamia of Eichler. Manu classified the plants more distinctly.
1. Oshadhis – annual plants.
2. Vanaspatis – trees bearing fruits without evident flowers.
3. Vrikshas – trees bearing flowers and fruits.
4. Guccha – bushy or shrubby plants.
5. Gulmas – succulent shrubs.
6. Trinas – grasses.
7. Pratnas – procumbent and decumbent herbs.
8. Vallis – twiners.
Charaka in his Charak-Samhita also gives a classification similar to the above. Susruta also follows a similar pattern. Apart from the above, the ancient Indians also classified plants according to their medicinal properties and dietic properties e.g. the ayurvedic systems of Charaka, Susruta and others.
Susruta classified medicinal plants under thirty seven ganas or sections. Plant classification, based upon their dietic properties was also attempted by Charaka and Susruta.
Regarding the system of nomenclature the ancient Indian system adopted double names – one based upon external features and the other based upon some special medicinal, dietic or other properties. This system of double naming is of course not synonymous with the binomial system devised by Linnaeus.
Period # 2. The Greek Period:
Theophrastus (370-287 B.C.) was a student and contemporary of Aristotle and was particularly interested in plants. His work is entitled De Historia Plantarum in which he described about 480 kinds of plants and divided them primarily on the basis of habit into trees, undershrub’s, herbs, cultivated and wild plants. Theophrastus followed the Platonic method of logical division i.e. any given object is either A or not A.
His main point of enquiry was: what is the essential nature? What is its difference. After Theophrastus we do not get any notable name in the field of botany or as a matter of fact in any of the branches of science. It seems the Greek civilization degenerated and died out towards the beginning of the Christian era.
Period # 3. The Roman Period:
With the advent of the Roman civilization we come across certain important works towards plant classification.
Pliny the Elder (23-79 A.D.) He was a Roman naturalist and mentioned nearly a thousand plants in his “Historical Naturalis”. This is a series of 37 books dealing with plants on the basis of medicinal properties, timber and practices of horticulture.
Dioscorides (first century A.D.) was a physician of Rome and worked in the military of Emperor Nero.
He complied De Materia medica in which he described about 600 species and gave their accounts and practical uses. The book included perfumes, oils, spices, cereals, condiments, wines etc. He even got the idea of groups such as the Labiates and Umbellifers. The book was documented with original illustrations increasing its value and usefulness greatly.
Period # 4. The Dark Age, Herbals and the Transition Period:
During the middle age a dark period descended over Europe and there was no significant botanical work. Most workers copied the work of Dioscorides without much addition. Wood cut of plants were prepared for illustrating them. Such were the herbals and included Albertus Magnus, Brunfels, Bock, Fuchs, Bauhin etc.
Albertus Magnus (1193-1280) – He was bishop of Ratisbon and is believed to have first differentiated monocots from dicots on the basis of stem structure.
Otto Brunfels (1464-1434) – He was first to describe and to some extent illustrate plants and distinguish perfecti and imperfecti groups of plants on the presence and absence of flowers.
Jerome Bock (1498-1554) – He was a herbalist and classified plants as herbs, shrubs and trees providing suitable notes on natural distribution of many plants. His famous work “New Krenterbuch” gave some fine description of plants.
Caesalpinio (1519-1637) – Wrote the book “De Plantis” consisting of sixteen books with description of 1500 plant species. His classification was also based upon herbs, shrubs and trees but within these he recognised the significance of fruit and seed characters. Caesalpinio is remembered by the genus Caesalpinia in the family Fabaceae.
Jean Bauhin (1541-1631), a French and Swiss physician, His important contribution was “Historia Plantarum Universalis”, in which he dealt about 5000 plants.
Gaspard Bauhin (1560-1624), brother of Jean Bauhin. Gaspard published “Pinax” (1623) containing names and synonyms of about 6000 species. He was the first to distinguish nomenclaturally between species and genus.
Joachin Jung (1587-1657), a German mathematician and the first terminologist. He was the first to define the following terms – nodes and internodes; blade and petiole; simple and compound leaf; stamens and styles etc.
John Ray (1627-1705) was an English philosopher and naturalist. In his ‘Methodus Plantarum’ 18000 species were classified. He established for the first time the presence of one or two cotyledons in the angiosperms classification.
His classification of the major groups was as follows:
A. Imperfectae i.e. flowerless (the cryptogams).
B. Perfectae i.e. flowering plants.
Dicotyledones-embryo with 2 cotyledons.
Monocotyledones-embryo with 1 cotyledon.
II. Arbores i.e. trees and shrubs:
Pierre Magnol (1638-1715) was a French botanist. He divided the plants into groups, what he called families. He was the first to give the concept of modern families. His name was commemorated by generic name Magnolia.
Joseph Pitton de Tournefort:
Joseph Pitton de Tournefort (1656-1708). He recognised petal bearing and nonpetal bearing flowers, corollas with separate and with united petals and regular and irregular corollas.
Rudolf Camerarius (1665-1721). He was professor and director of botanical garden at Germany. He established the fact of sexuality in flowering plants.
Period # 5. Modern Period:
The modern period of classification starts with Linnaeus and continues even today. During this period numerous systems have been proposed. Broadly speaking they belong to the pre-Darwinian period and post-Darwinian period. Before Darwin the concept of evolution was not an accepted principle and the general belief was in the fixity of species.
In the post-Darwinian period evolutionary theory brought about a fundamental change in the concept of classification. Generally speaking in the pre-Darwinian period the systems proposed were either artificial or natural.
An artificial system is one which plants classifies according to a few convenient characters for the purpose of identification without paying any attention to affinities. Linnaeus’ sexual system is an example of artificial system.
In fact all classifications prior to Linnaeus were also artificial. A natural system is one which is based upon overall resemblances between plants and groups taking external morphology as the main criterion. Systems of classifications after Linnaeus but prior to Darwin are supposed to be natural systems.
A phylogenetic system on the other hand tries to determine evolutionary relationships of plants and groups and arrange them accordingly. Thus those plants which were evolutionarily more related would stand closer together than those which were distantly related. Such systems as those of Endlicher, Eichler, Engler, Rendle and Hutchinson would come under this category.