Classification systems of Angiosperms.pptx

The slide includes Bentham Hooker's natural system, Engler and Prantl's and Hutchinson's Phylogenetic system and APG III system

1. CLASSIFICATION SYSTEM Presented by Dr. Upakar Rai Department of Botany St. Joeph’s College, Darjeeling WB

2. CLASSIFICATION SYSTEM Arrangement of plants into groups based upon similarity and differences Groups assembled in larger inclusive group sharing some commonality Based on artificial character, overall similarities on morphology and phenetic relationship

3. BENTHAM AND HOOKER’S SYSTEM OF CLASSIFICATION Genera Plantarum – 3 volumes (1860 – 1883) Contains descriptions of 202 families and 7567 genera Based on refinement of AP deCandole and Lindley Grouping done b ased on natural affinities actually studied on specimen on field Followed throughout the herbaria of world (Colonial countries)

4. PHANEROGAMS Seed bearing Plants DICOTYLEDONS GYMNOSPERMAE MONOCOTYLEDONS POLYPETALAE GAMOPETALAE MONOCHLAMYDEAE SERIES 1. Thalamiflorae 6 Ords , 34 Fam 2. Disciflorae 4 Ords , 23 Fam 3. Calyciflorae 5 Ords , 27 Fam SERIES 1. Inferae 3 Ords , 9 Fam 2. Heteromerae 3 Ords , 12 Fam 3. Bicarpellatae 4 Ords , 24 Fam. SERIES 1. Curvembryeae 7 Families 2. Multiovulatae acuitacea 1 Family 3. M. terestres 3 Families 4. Microembryeae 4 Families 5. Daphnales 5 Families 6. Achlamydosporae 3 Families 7. Unisexuales 9 Families 8. Ordines anamoli 4 Families 1. Gnetaceae 2. Coniferae 3. Cycadaceae SERIES 1. Microsporae 3 Families 2. Epigyneae 7 Families 3. Coronarieae 8 Families 4. Calycinae 3 Families 5. Nudiflorae 5 Families 6. Aposporae 3 Families 7. Glumaceae 5 Families Sub-class Class Petals free Petals fused Incomplete flowers Outline of Bentham and Hooker’s System of Classification 3 Classes 3 Sub-classes 21 Series (14 Dicot; 7 Monocot) 25 Cohorts (Dicot) 202 Natural Orders (165 Dicot; 34 Monocot)

5. MERITS OF BENTHAM AND HOOKER’S SYSTEM OF CLASSIFICATION Has p ractical value for identification of plants; easy to follow for routine identification F ollowed throughout the herbaria of the world to arrange the specimen. B ased on careful examination of actual living plant specimen. Gymnosperms are placed in a separate class as against earlier workers. Ranales (a primitive group) is placed at the beginning of Dicotyledons. Dicotyledons placed before monocotyledons. Description of family and genera are precise with key to identification. Arrangement of taxa are based on overall natural affinities

6. DEMERITS OF BENTHAM AND HOOKER’S SYSTEM OF CLASSIFICATION The system does not incorporate phylogeny Gymnospermae is placed between Dicotyledons and Monocotyledons Monochlamydeae is an unnatural assemblage. Unisexualis is a loose assemblage of diverse families. 4 Families relation not certain and placed in Ordine Anamoli . Large families like Urticaceae, Euphorbiaceae and Saxifragaceae have been split into smaller and more natural grouping by subsequent authors. Orchidaceae placed in microsporae is placed towards the beginning of monocotyledons. Series Inferae is placed before other two series having superior ovary.

7. ENGLER AND PRANTL SYSTEM OF CLASSIFICATION Heinrich Gustave Adolf Engler and Karl A.E. Von Prantl proposed 1 st Phylogenetic system after ‘Origin of Species’ Classification is based on Eichler’s system of classification Information from anatomy, embryology, geography in addition to morphology Die- Naturelichen Pflanzenfamilien 23 Vol. 1887-1915 Includes all plant groups – Algae, Bryophytes higher plants Classified and described down to genus level Taxonomic groups are arranged in linear sequence from simplest to complex characters It soon replaced the Bentham and Hooker’s system in European and American herbaria

8. Distinctive features of Engler and Prantl’s System Families arranged in ascending order based on increasing complexities Abolition of Monochlamydeae Monocotyledons placed before Dicotyledon Natural orders replaced by Family Series and Cohorts replaced by Orders Detailed description of all plant grpoups

9. Engler and Prantl’s Classification All plant divided into 13 divisions; 13 th Division dealt with Flowering plants ( Embryophyta Siphonogama ) Divided into 2 sub-division - Gymnospermae and Angiospermae Angiosperms (51 orders; 283 families) divided into 2 Classes (Monocotyledons and Dicotyledons Dicotyledons divided into 2 sub-classes Archichlamydeae and Metachlamydeae

10. EMBRYOPHYTA SIPHONOGAMIA Flowering Plants DICOTYLEDONEAE GYMNOSPERMAE MONOCOTYLEDONEAE ARCHICHLAMYDEAE METACHLAMYDEAE ORDERS 1. CYCADOFILICALES 2. CYCADACEAE 3. BENNETTITALES 4. GINGKGOALES 5. CORDAITALES 6. CONIFERAE 7. GNETALES Sub-class Sub-Division 30 Orders, 186 Families 10 Orders, 52 Families ANGIOSPERMAE Class 11 Orders, 45 Families An outline classification given by Engler and Prantl in Die- naturelichen Pflanzenfamilien Angiosperm – 51 Orders; 283 families

11. MERITS OF ENGLER AND PRANTL SYSTEM OF CLASSIFICATION First system to incorporated the ideas of organic evolution Classification includes entire plant kingdom; provided description and identification keys . Gymnosperm treated separately and placed before angiosperms . Many large families of B&H splitted to smaller natural families. Polypetalae and M onochlamydeae was abolished related families kept together. Compositae and Orchidaceae treated as highly evolved groups. Very convenient and used in flora and herbaria. Cohorts, natural orders replaced with Orders and families

12. DEMERITS OF ENGLER AND PRANTL SYSTEM OF CLASSIFICATION Not a true phylogenetic system. Many ideas are outdated Monocotyledons is placed before Dicotyledons Amentiferae is regarded as primitive, which is relatively an advance family. Dichlamydous forms is believed to have evolved from monochlamydous forms. Angiosperms considered as a polyphyletic group. Primitive family Helobieae is placed after Pandanales – a relatively advance group . Primitive Ranales placed after Amentiferae .

13. Contribution of other Botanist John Hutchinson – Royal Botanic Garden Proposed Phylogenetic system in Families of Flowering Plants (1926 and 1935) Classification revised in his book Evolution and Phylogeny of Flowering Plants 1959; final revision came out in 1973 He traced 2 lines of evolution; one towards woody habit arising from Magnolials and other towards herbaceous habit from Ranale ancestor Monocot arose from common ancestor that gave rise to Ranales Classification based on principles of contrasting characters of primitiveness and advanceness

14. 1. The evolution is both upward and downward, the former tending towards preservation and the later to their reduction and degeneration of characters. 2. Evolution does not necessarily involve call for organs at one time or simultaneously. 3. Aquatic plants are derived from terrestrial and saprophytes, parasites, and epiphytes are more recent. 4. Trees and shrubs are more primitive than herbs. 5. Perennials are more primitive than biennials and annuals. 6. Plants with vascular bundles arranged in a ring are more primitive those in which vascular bundlers are scattered. 7. Spiral phyllotaxy is primitive than whorled and opposite phyllotaxy. John Hutchinson’s Principles

15. 8. Dioecious plants are more advanced than bisexual flowers. 9. Unisexual flower are more primitive than bisexual flowers. 10. Petaloid flowers are more primitive than bisexual flowers. 11. Gamopetally is more advanced than polypetalae . 12. Zygomorphic flower are more advanced than actinomorphic flowers. 13. Hypogyny is more primitive than perigyny and epigyny . 14. Simple leaves are more primitive than compound leaves. 15. Solitary flower is more primitive than inflorescened flowers. 16. Spirally imbricate floral parts are more primitive than whorled and valvate arrangement.

16. 17. Apocarpy is more primitive than syncarpy. 18. Polycarpy preceedes oligocarpy . 19. Endospermic seeds with small embryo are more primitive than non endospermic seeds with large embryo. 20. Flowers with numerous stamens are more primitive than those with fewer stamens. 21. Free stamens precede the fused ones. 22. Aggregate fruits are more evolved than single fruit and capsule preceedes berry or drupe. 23. Parietal placentation is more primitive than axial and free central placentation. 24. Trees or arboreal habit are more primitive than climbers are twiners in any one family or genus.

17. An outline classification given by Hutchinson 2 nd edition (1959) FLOWERING PLANTS DICOTYLEDONEAE GYMNOSPERMAE MONOCOTYLEDONEAE LIGNOSAE HERBACEAE Division Phyllum 54 Orders 28 Orders ANGIOSPERMAE Sub- phyllum GUMIFLORAE CALYCIFERAE COROLLIFERAE Division 3 Orders 14 Orders 12 Orders FLOWERING PLANTS DICOTYLEDONEAE GYMNOSPERMAE MONOCOTYLEDONEAE ARCHICHLAMYDEAE METACHLAMYDEAE Division Phyllum ANGIOSPERMAE Sub- phyllum An outline classification given by Hutchinson first edition (1926-34) GUMIFLORAE CALYCIFERAE COROLLIFERAE Division 59 Orders, 213 Families 17 Orders, 52 Families 3 Orders, 6 Families 14 Orders, 28Families 12 Orders, 34 Families

18. Arthur Cronquist – American Botanist (Compositae specialist) Proposed Phylogenetic system in The evolution and classification of flowering plants 1968 Integrated system of Classification of Flowering Plants 1981 and revised in 1988 Classification based on information from various branches of Botany

19. MAGNOLIOPHYTA Flowering Plants MAGNOLIOPSIDA ( Dicotyledons ) LILIOPSIDA (Monocotyledons) SUBCLASS 1. MAGNOLIIDAE 8 Orders, 39 Families 2. HAMAMELIDAE 11 Orders, 24 Families 3. CARYOPHYLLIDAE 3 Orders, 14 Families 4. DILLENIIDAE 13 Orders, 78 Families 5. ROSIDAE 18 Orders, 114 Families 6. ASTERIDAE 11 Orders, 49 Families SUB-CLASS 1. ALISMATIDAE 4 Orders, 16 Families 2. ARECIDAE 4 Orders, 6 Families 3. COMMELINIDAE 7 Orders, 16 Families 4. ZINGIBERIDAE 2 Orders, 9 Families 5. LILIDAE 2 Orders 19 Families Class Outline of Arthur Cronquist System of plant classification (1988)

20. Fig: Putative evolutionary relationships among the sub-class of dicotyledons . The size of the balloon is proportional to the number of species in a group. Fig: Putative evolutionary relationships among the sub-class of Monocotyledons.

21. Angiosperm Phylogeny Group (APG-III) Informal international group of systematic botanists Collaborative classification system that tries to establish a consensus on taxonomy of flowering plants based upon phylogenetic studies (molecular studies) Strongly believed in monophyletic origin of angiosperms Prior classification is based on morphology and biochemistry Typically produced by individual or small group (resulted into large no of classification Different countries favoured different classification system – no consensus Major herbaria are adopting APG system for arranging their collection

22. In the 1990s major developments of DNA sequencing technology and computing power ushered into new era of classification In 1993, Mark Chase and his co-workers analyzed 5000 plants for genes involved in photosynthesis An informal group of botanists took an initiative to analyze the plant genetic material (chloroplast DNA and ribosomal 18s DNA) under the Angiosperm Phylogeny Group (APG) with an intention to provide widely accepted and more stable point of reference of angiosperm classification in 1998 – APG I Since then 3 revisions APG II (2003), APG III (2009), and APG IV (2016) have been published. New era in the classification system

23. Principle of APG The Linnean system of orders and families should be retained Groups should be monophyletic (the existing system do not have this property) A broad approach is taken to defining the limits of group (single family and genus in a group is avoided) Above the level of families and orders, name ‘clades’ are used

24. APG III was published in 2009 (3 rd version), mostly based on molecular data The system consists of 59 orders (including 14 new orders) and 415 families (42 fewer than previous system) Designation of Alternative “Bracketed families” was abandoned in APG III because of it unpopularity 54 of 55 BF and 18 families of APG II were dropped out 10 families (against 39 in APG II) are not placed in any order in APG III 20 families which did not find place in APG II were accepted and realignment of few families was done in APG III APG III Classification (2009)

25. The system shows monophyletic origin The system includes multiple data from morphology , anatomy, embryology, biochemistry and molecular data Groups name upto orders have been assigned Traditional divisions of angiosperms into monocotyledons and dicotyledons has not been taken into account. Many monocots are put in between primitive angiosperms and eudicots, thereby solving the problems of paraphyly among monocots and dicots The No. of cladograms in the classification shows general affinities between various groups Merits of the classification

26. 6. Primitive families are placed at the beginning of the angiosperms 7. The merger of Budlejaceae and Myotoraceae and Scrophulariaceae have been supported from morphological and molecular evidences given by Bermer et al. (2001) and Olmstead (2001) 8. Multigene analysis and morphological data are the basis on which Winteraceae and Cancellaceae are kept under the same order 9. Monophyletic concept is reflected in Malvaceae where families like Tiliaceae , Sterculiaceae and Bombacaceae are included in former. This inclusion is supported by molecular as well as morpholocical data 10. The concept of braceted families in earlier APG has been removed in APG III

27. This classification is applicable only up to families The fate of some unplaced families and few replaced genera is still uncertain Botanical nomenclature has not been assigned to new groups Demerits of the classification