Asteraceae

SELVAM BOTANY IMsc bdu university tamilnadu

1. ASTERACEAE ( compositae ) G SELVAM I.M.SC.BOTANY BHARTHIDASAN UNIVERSITY, TRICHY TAMILNADU

2. CLASSIFICATION SYSTEMATIC POSITION Class - Dicotyledons Sub-class - Gamopetalae Series - Inferae Order - Asterales Family - Asteraceae

3. DISTRIBUTION The family Asteraceae includes about 950 genera with probably 20,ooo species. The family comparises about 10% of the total number of flowering plants. In india family is represented by 697 species . They can live in all types of localities such as deserts , arctic regions and aquatic habitats

4. Vegetative Characters Habitat : The plants are usually herbaceous annuals or shrubs. The plants contain a milky or watery or resinous sap. Outer surface of these plants is covered with different types of hairs. ROOT : The roots constitute a branched , tap-root system. STEM : The stem is herbaceous or woody and erect. It is tuberous in Helianthus tuberosus and leaf-like in Baccharis .

5. LEAVES : The leaves are usually alternate , simple , petiolate and extipulate . In some species leaves are opposite ( eg. Helianthus ) or whorld ( eg. Eupatorium ). Sometimes , The leaves may be pinnately or palmately lobed. leaf Surface is covered with hairs. Leaf margin may be entire or Serrate.

6. FLORAL CHARACTERS INFLORESCENCE : The inflorescence is a racemose or capitulum . A capitilum consists of disc florets in the centre surrounded by ray florets and an involucre. The florets are arranged in centripetal manner. The extended base of the capitulum is called a receptacle. FLOWER : The flower are bisexual or unisexual or polygamous, rarely neuter. They usually pentamerous , bracteates, sessile and epigynous . There are two types of flowers, namely Disc florets and Ray florets .

7. TWO TYPES OF FLOWERS

8. TWO TYPES OF FLOWER DISC FLORET RAY FLORET

9. DISC FLORET : The disc floret occupy the centre of the capitulum . They are bracteates, sessile , bisexual, regular, actinomorphic and epigynous . CALYX : The calyx is usually represented by a pappus . The pappus is considered to be a reduced and highly modified calyx. In some cases, the calyx is represented by spines

10. COROLLA : The corolla is tubular or discoid. It consists of 5 united petals ( Gamopetalous ). Aestivation is valvate . The corolla tube is swollen near the base of the style. ANDROECIUM : The Antroecium consists of 5 epipetalous stamens. The stamens are alternate to petals. The filaments remain free, but anthers are united into a tube around the style. This is called Syngenesious condition. The anthers are dithecous , introse and dehiscing by longitudinal slits. GYNOECIUM : The gynoecium is bicarpellary and syncarpous . Ovary is inferior and unilocular . There is a single anatropous ovule in the locule on basal placentation. The style is slender and branched. There are two stigmas with various forms.

11. FRUIT : The fruit is a cypsela with pappus . SEED : The seed is dicotyledonous and exalbuminous . RAY FLORET : Ray floret occupy the periphery of capitulum . They are bracteates, sessile, irregular, zygomorphic, ligulate and epigynous . CALYX : The calyx is pappus -like or absent.

12. COROLLA : The corolla is ligulate (strap-shaped), eg . Bilabiate (the upper lip is 3-lobed and lower lip is 2-lobed. It consists of 5 fused petals ( Gamopetalous ). Aestivation is valvate . ANDROECIUM : In homogamous heads, the ray flower are bisexual so they have 5 syngenesious stamens.In heterogamous heads, ray florets are usually pistillate or neuter, so stamens are altogether absent.

13. GYNOECIUM : Bicarpellary , syncarpous , inferior ovary with a single locule as in disc florets ovule is one and placentation is basal. Style is bilobed and stigma is variable. FRUIT : Cypsela SEED: Dicotyledonous and exalbuminous .

14. COMMON PLANTS Helianthus annuus ( Suryakanthi ) Eclipta prostrata ( karisilanganni ) Tridax procumbens ( Vettukkaaya-thalai )

15. Tagetes erecta ( sevvannthi ) Calendula officinalis ( Thulukka Saamanthi )

16. Tridax procumbens

17. CLASSIFICATION SYSTEMATIC POSITION CLASS - Dicotyledone Sub-class - Gamopetalae Series - Inferae Order - Asterales Family - Asteraceae Genus - Tridax Species - procumbens

18. Tridax procumbens HABITAT : Tropical and sub-tropical regions, perennial herb. STEM : Cylindrical, branched, erect. LEAF : Simple, ovate, serrate margin, Reticulate ,opposite decussate , Aromatic. INFLORESCENCE : Head or capitulum

19. RAY FLORET : Bracteate , zycomorphic , sessial,unisexual , Peripharal . Calyx : pappus like structure. COROLLA : 3 or 4 valvate Aestivation Gamopetalous , Androecium and Gynoecium absent.

20. DISC FLORET : Bracteate , Actinomorphic, bisexual , Inferior ovary. CALYX : pappus like structure. COROLLA : 5 Gamopetalous valvate Aestivation. ANDROECIUM : Syngenesious stamens. GYNOECIUM : Bicarpellary , syncarpous , unilocular , basal Placentation, style, slender and branchd , inferior ovary. FRUIT : Cypsela

21. ECONOMIC IMPORTANCE 1.OIL : Many plants gives oil seeds to extract oils. The oil is used for cooking, burning, soap-making, varnish preparations and as lubricant. Examples – Helianthus annuus ( Suryakanthi ) – Seed Carthamus tinctorius ( Sendurakam ) – Flower Guizotia abyssinica ( Payellu ) – Seed 2.DYES : Some plants yield dyes for colouring different materials. Flower heads of Carthamus tinctorius gives a red dye called safflower. Flower heads of Tagetes erecta ( Tulukka-samandi ) gives a yellow-dye for colouring cotten

22. 3.FOOD : Leaves of Cichorium intybus ( kasini keerai ) are used in salads. Root powder of those plants is a substitute for coffee or often mixed with coffee. Leaves Lactuca sativa ( Lattuce keerai ) is used in salads. 4.MEDICINES : Whole plant extract of Artemisia absinthium ( machipattri ) is given for fever and inflammation of liver. Artemisia vulgaris ( makkippu ) is used for round worms, fever, asthma and nervous disorders.

23. 5.ORNAMENTAL PLANTS : Tagetes erecta ( sevvanthi ) Helianthus annuus ( Suryakanthi )

24. Calendula officinalis ( Thulukka saamanthi ) Parthenium hysterophorus ( mookuthi poo)