The contributions are arranged as numbered lists for each taxonomist with the most important ones at the beginning. You don’t have to learn the complete note as it is, prepare them as shortnotes maximum 10 points for each taxonomist, choose them according to your own preference.
Major Contribution of Theophrastus (372 BC to 287 BC) – Father of Botany
Theophrastus was a Greek naturalist, he was student of Pluto and Aristotle. After Aristotle’s death, he inherited his library and the garden. Theophrastus is credited with having authored more than 200 works most of which survive as fragments or as quotations in the works of other authors. Two of his botanical works have survived intact, however, and are available in English translations: Enquiry into plants (1916) and The Causes of plants (1927). During his conquests, Alexander the Great made arrangements to send back materials to Athens, enabling Theophrastus to write about exotic plants such as cotton, cinnamon and bananas. His major contribution to botany are:
1. Theophrastus described about 500 kinds of plants, 2. He classified plants into four major groups: the trees, shrubs, subshrubs and herbs. 3. He recognized the differences between flowering plants and non-flowering plants, 4. He recognized the differences between dicotyledons and monocotyledons, superior ovary and inferior ovary, free and fused petals and also fruit types. 5. He was aware of the fact that many cultivated plants do not breed true. 6. Several names used by Theophrastus in his De Historia plantarum, e.g. Daucus, Crataegus and Narcissus, to name a few, are in use even today.
Major Contributions of Carolus Linnaeus (1707-1778)—Father of taxonomy Carolus Linnaeus, was a Swedish naturalist. Linnaeus published his first paper on the sexuality of plants in 1729. In 1730, he published Hortus upplandicus, enumerating the plants in the Uppsala Botanical Garden according to the Tournefort’s system. Faced with problem of increasing numbers of plants which he found hard to fit in Tournefort’s system, he published a revised edition of Hortus upplandicus with plants classified according to his own sexual system. 1. He published Systema naturae in 1735, in which he presented an outline of his sexual system of classification. 2. Linnaeus published several manuscripts, including Genera plantarum (1737). In his Genera plantarum, he listed and described all the plant genera known to him. 3. He published his best known Species plantarum in 1753. In Species plantarum, he listed and described all the known species of plants. For each species there was : i. A generic name ii. a polynomial descriptive phrase or phrase-name commencing with generic name and of up to twelve words, intended to serve as description of the species, iii. a trivial name or specific epithet on the margin; iv. synonyms with reference to important earlier literature; and v. habitats and countries.
4. The generic name followed by the trivial name formed the name for each species. Linnaeus thus established the binomial nomenclature, first started by Caspar Bauhin and the generic concept, started by Tournefort.
Major Contributions of John Hutchinson(1884-1972) John Hutchinson was a British botanist associated with the Royal Botanic Gardens, Kew, England who also served as keeper of Kew herbarium for many years. 1. Hutchinson first proposed his classification of angiosperms in his book The Families of Flowering Plants, the first volume on Dicotyledons appearing in 1926 and the second on Monocotyledons in 1934. The classification was revised periodically, second edition in 1959 and the 3rd in 1973. 2. In addition to presenting his system of classification for angiosperms, Hutchinson also published valuable works such as Flora of West Tropical Africa (1927-29), Common Wild Flowers (1945), A Botanist in South Africa (1946), Evolution and Classification of Rhododendrons (1946), British Flowering Plants (1948), More Common Wild Flowers (1948), Uncommon Wild Flowers (1950), British Wild Flowers (1955), Evolution and Phylogeny of Flowering Plants (1969) and Key to the Families of Flowering Plants of the World (1968).(learn two or three names) 3. Hutchinson also embarked upon an ambitious plan of revising Genera plantarum of Bentham and Hooker under the title The Genera of Flowering Plants. Unfortunately he could complete only 2 volumes of this work, published in 1964 and 1967. 4. The classification system of Hutchinson, is based on 24 phylogenetic principles, and studies of a large number of plants at his disposal at Kew. 5. The 24 principles included General principles, Relating to General Habit, Relating to General Structure of Flowering plants and those Relating to Flowers and Fruits. 6. The classification system of Hutchinson dealt only with the flowering plants, included under Phylum Angiospermae as distinct from Phylum Gymnospermae. 7. Hutchinson considered flowering plants to be monophyletic, having evolved from the hypothetical cycadeoid ancestral group which he gave the name of Proangiosperms. 8. He established Magnoliales as an order distinct from Ranales, he regarded Magnoliaceae as the most primitive family of the living angiosperms. 9. He considered Dicotyledones to be more primitive and placed them before Monocotyledones, giving them a rank of Subphylum. 10.He also considered Monocotyledones to be a monophyletic group derived from Ranales, 11.He classified taxa based on combination of characters and not one or a few characters as in earlier systems. 12.He provided detailed classification up to the generic level, description of very high standard and useful keys for the identification of families.
Major contributions of Armen Takhtajan (1910–2009) Armen Takhtajan was a leading Russian plant taxonomist and chief of the Department of higher plants in V.L. Komarov Botanic Institute, USSR Academy of Sciences, Leningrad (now named St. Petersburg). Takhtajan, who has provided a classification of angiosperms up to the family level, belonged to the Besseyan School and was strongly influenced by Hutchinson, Hallier and the other more progressive German workers. 1. He was an international authority on phytogeography, origin and phylogeny of flowering plants. 2. He was the President of the 12th International Botanical Congress held in Leningrad in 1975. 3. His classification was first published in 1954 in Russian, but came to be known outside the Soviet Union only after its English translation Origin of Angiospermous Plants was published in 1958. 4. His final comprehensive system of classification was published in 1997 (Diversity and Classification of Flowering Plants). 5. Earlier Takhtajan, along with Cronquist and Zimmerman, also provided a broad classification of Embryobionta (1966). 6. While deciding the placement of various groups, Takhtajan used a number of criteria and based on his understanding of the available information. He developed his classification system based on phylogenetic, as well as phenetic information from every field of study, however he relied more heavily on phylogenetic data. 7. He believed in the monophyletic origin of angiosperms, the group having evolved from seed ferns Lyginopteridophyta. 8. According to Takhtajan, the angiosperms are of neotenous origin (retention of juvenile characters in the adult plant). Takhtajan was of the opinion that angiosperms arose under environmental stress, probably as a result of adaptation to moderate seasonal drought on rocky mountain slopes, in an area with monsoon climate. 9. He considered Degeneriaceae as the most primitive family and placed it under the order Magnoliales. 10.Takhtajan named angiosperms as division Magnoliophyta. Dicots and monocots are given the rank of a class and named Magnoliopsida and Liliopsida, respectively. These are further subdivided into subclasses (ending in -idae, e.g. Rosidae), superorders (ending in -anae, e.g. Rosanae), orders and families. systems are developed 11.His system is more phylogenetic than that of Hutchinson and other earlier authors and is based on now widely accepted phylogenetic principles. 12.The derivation of Monocotyledons from the terrestrial hypothetical extinct group of Magnoliidae (often called proangiosperms), is largely favoured, as also the view that Alismatales and Nymphaeales represent ancient side branches and have a common origin. 13.Abolition of artificial group names Polypetalae, Gamopetalae, Lignosae, Herbaceae etc. has resulted in more natural grouping of taxa 14.Nomenclature is in accordance with the International Code of Botanical Nomenclature, 15.even up to the level of division. 16.Depiction of the putative relationships of major subclasses and superorders with the help of a bubble diagram is very useful. It gives some idea about the relative size of different groups, 17.point of cladistic divergence and degree of advancement (apomorphy) reached. Larger groups are represented by larger bubbles, vertical length the degree of advancement, and the point of separation of a branch its cladistic divergence. 18.Takhtajan’s use of the ending -anae, was earlier opposed in favour of -florae but has now been accepted by G. Dahlgren (1989) and Thorne (1992 onwards) since the ending-florae restricts the usage to angiosperms and is not universal in application.
Arthur Cronquist (1919-1992), Arthur Cronquist was a leading American taxonomist, associated with the New York Botanical Garden. 1. He produced a broad classification of Embryobionta along with Takhtajan and Zimmerman (1966). 2. He produced a detailed classification of angiosperms in 1968 in his book The Evolution and Classification of Flowering Plants. The classification was further elaborated in 1981 in his book An Integrated System of Classification of Flowering Plants.The final revision was published in the second edition (1988) of The Evolution and Classification of Flowering Plants. Some realignments in Dicotyledons were published in Nordic Journal of Botany in 1983. 3. The text of classification, being in English, has been readily adopted in books and floristic projects originating in the USA. 4. The classification is conceptually similar to that of Takhtajan’s system, but differs in details. 5. The classification, like that of Takhtajan, is based on evidence derived from all sources, but in contrast to Takhtajan who gives more importance to cladistics, Cronquist gave more importance to morphology. 6. The classification of Cronquist is largely based on principles of phylogeny that find acceptance with major contemporary authors. 7. The revision of the classification in 1981 and 1988 was presented a in comprehensive form, giving detailed information on phytochemistry, anatomy, ultrastructure and chromosomes besides morphology. 8. Following Takhtajan, the angiosperms are given the name Magnoliophyta and divided 9. into Magnoliopsida (dicots) and Liliopsida (monocots). Cronquist includes only six subclassesin dicots and recognizes five in monocots. 10.In dicotyledons, the Ranunculidae of Takhtajan are merged with Magnoliidae and Lamiidae are not given a separate rank at subclass level, but retained in Asteridae. In monocotyledons, Zingiberidae are treated separate from Liliidae and Triuridales kept under Alismatidae. 11.As a major departure from the systems of Takhtajan, Dahlgren and Thorne, no superorders are recognized, the subclasses are divided into orders directly. 12.Also, as against 233 orders and 592 families recognized by Takhtajan, Cronquist recognizes 83 orders and 386 families. 13.Unlike most recent authors, Cronquist believed in the aquatic origin of monocotyledons, from a primitive vessel-less ancestor resembling present-day Nymphaeales. 14.Cronquist has provided a synoptic arrangement of taxa, facilitating the process of identification up to the family level. 15.The relationships of various subclasses and orders are shown with the help of a phylogram which takes the form of a bubble diagram, like other contemporary systems of classification. 16.He rightly placed Winteraceae at the beginning of dicotyledons. The family has vessel-less wood similar to gymnosperms, great similarity between micro- and megasporophylls, unifacial stamens and carpels, morphology similar to pteridosperms, high chromosome number suggesting long evolutionary history and less specialized beetle pollination as compared to the genus Magnolia. 17.Abolition of artificial group names such as Polypetalae, Gamopetalae, Lignosae, Herbaceae etc. has resulted in more natural grouping of taxa. 18.Nomenclature is in accordance with the International Code of Botanical Nomenclature. 19.Placement of Magnoliidae as the most primitive group of angiosperms, dicotyledons before monocotyledons, Magnoliales at the beginning of Magnoliidae and Butomaceae at the beginning of Liliopsida, finds general agreement with other authors. 20.Compositae in dicotyledons and Orchidaceae in monocotyledons are generally regarded as advanced families, and are rightly placed towards the end of each group, respectively. 21.The relationship of various groups has been depicted with diagrams, which provide valuable information on relative advancement, cladistic relationship and size of various subclasses. 22.The separation of Brassicaceae and Capparaceae has found support from chloroplast sequence data consistent with morphological data.