. Hutchinson System of Classification John Hutchinson was a British botanist associated with Royal Botanical Garden, Kew England. He proposed a phylogenetic system of classification based on evolutionary relationship among plants. He (1926-1934) published his system of classification in his book “Families of Flowering Plants” in two volumes. He described almost 411 families in his book. He published his first book of ‘Families of Flowering Plants’ in 1926 dealing with whereas he published his second book in 1934 dealing with . As described earlier, phylogenetic system of classification proposed by Hutchinson based on evolutionary relationship considered following assumptions:  Plants with sepal and petals are primitive than plants with without sepals.  Free floral parts are primitive over connate or agate flower parts.  Spiral arrangement of flower parts such sepals, petals and staments are primitive than spiral arrangement.  Bisexual or hermaphrodite conditions are primitive than unisexual flowers.  Actinomorphic flowers are primitive whereas zygomorphic flowers are advanced.  Solitary flowers are primitive over flowers with inflorescence.  Hypogynous or superior ovary are primitive over epigynous (inferior) or perigynous ovary.  Indefinite number of flowers are more primitive than few or limited number of floral parts.  Complete flower with all floral parts are primitive over incomplete flower.

Basics principles of Hutchinson system of classification

Hutchinson classified plant kingdom following 24 basic principles or phylogenetic dycta which have been discussed below:

1. Evolution occurs in both directions i.e. upward and downward. Upward evolution results into preservation whereas downward results into reduction or degeneration of characters. 2. Evolution (progressive) involves only few organs at a time and other remains stationary or degenerating. 3. Evolution is consistent and established evolution appears in end of the phylum. 4. Trees and shrubs are primitive over herbs. 5. Trees and shrubs are primitive than climbers. 6. Aquatic plants have arisen from terrestrial plants. Saprophytes and parasites are more advanced. 7. Perennials are primitive over and older than biennials and annuals. 8. Dicotyledonous plants with collateral vascular bundles are more primitive than monocots with scattered vascular bundles. 9. Spiral phyllotaxy (leaf arrangement) is primitive over whorled and opposite phyllotaxy. 10. Simple leaves are primitive than compound leaves. 11. Dioecious plants are more advanced than monoecious plants. 12. Unisexual flowers are advanced over bisexual flowers. 13. Solitary flowers are older than flowers in inflorescence. 14. Polymerous flowers are primitive than oligomerous flowers. 15. Apetalous flowers are advanced over petalous flowers. 16. Polypeataly (united) is primitive over gamopetaly (free). 17. Zygomorphic flower are more advanced than actinomorphic flowers. 18. Hypogyny is more primitive than perigyny and epigyny. 19. Apocarpy (free carpel) is more primitive than syncarpy (connate carpel). 20. Polycarpy (many carpel) precedes oligocarpy (few carpel). 21. Non-endospermic seeds with large embryo are advanced over endospermic seeds with small embryo. 22. Indefinite number of stamens is more primitive than flowers with few stamens. 23. Flowers with free stamens precede the flowers with fused stamens. 24. Single fruit plant is more primitive than aggregate fruit. Following above 24 phylogenetic dycta, Hutchinson proposed phylogenetic system of classification, outline of which is mentioned below: Hutchinson supposed monophyletic origin of angiosperm (from Proangiosperms) and classified Angiosperm into sub-phylum viz. Dicotyledonae (embryo with two cotyledons) and monocotyledonae (embryo with single cotyledon). Characters of Dicotyledons Plants with tap roots, reticulate venation of leaf, pentamerous flowers and two cotyledons in embryo. Characters of Monocotyledons Plants with fibrous adventitious root, parallel venation of leaves, trimerous flowers and one cotyledon in embryo. Sub-Phylum I - Dicotyledons are further divided into two divisions viz. Lignosae and Herbaceae. Division I - Lignosae  They generally include trees, shrubs and woody plants.  It comprises 54 orders and 251 families. Order starts with and ends with Verbenales passing through Anonales - – Leguminales – – and Rubiales; whereas family starts with Magnoliaceae of order Magnoliales and ends with Phrymaceae of order Verbenales. Division II – Herbaceae  This division includes all annual, biennials and perennial herbaceous plants.  This division comprises 28 orders and about 100 families. Order starts with and passing through Rhoedales - Parietales – Umbellelaes – and ends with Personales. Family starts with and ends with Lamiaceae or Labiatae. Sub-Phylum I – Monocotyledons - Based on nature of calyx and corolla (perianth), Monocots are further divided into three divisions viz. Calyciferae, Corolloferae and Glumiflorae. Division I - Calyciferae  Flowers belonging to plants of this division consist of separate and distinct calyx and corolla  Sepals and petals are coloured. Sepals are green whereas petals are of different olour.  This division comprises 12 orders. Order starts with Butamales and ends with . Family starts with Butamaceae and ends with . Division II – Corolliferae  This division includes all those flowers which have sepals and petals with no difference in coloration.  This division consists of 14 orders starting with and ending with . Family starts with and ends with . Division - III – Glumiflorae  This division includes flowers which have reduced perianth.  Lodicules may be present.  This comprises 3 order and 6 families. Order starts with and ends with Graminales. Family starts with and ends with . Merits  It is based on natural characteristics of plants and evolutionary relationship among them.  It is very practical and valuable in identification as key features have been mentioned.  Placement of monocots after dicots is very accurate and practical.  Placement of Magnoloales in arborescent plants and that of Ranales in herbaceous plants is quite justified.  Some large orders are broken into small orders and some large families is elevated as a rank of order. Demerits In spite of great effort Hutchinson to classify the Angiosperm and wide acceptance by taxonomists, few drawbacks have been raised, some of which have been mentioned below:  Some of the closely related families have been separated and placed into different groups. E.g. Ranunculaceae and Magnoliaceae.  Similarly, Lamiaceae and have been separated.  More focus is on monophyletic origin of Angiosperm from Proangiosperm.  Classification on the basis of woody and herbaceous nature of plants has resulted into separation of closely related families.