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

22. 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

23. 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.

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

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