This document provides information about the Asteraceae (Sunflower or Aster) family of flowering plants. It discusses the family's large geographical distribution, taxonomy according to different scholars, morphological characteristics including leaves, inflorescence, flowers, and fruits. It also outlines some economic uses of Asteraceae plants such as food, oil, rubber, insecticides, ornamentals, and medicinal properties. Taxonomists have assigned different systematic positions to the family over time.
1. ASTERACEAEDum. (nom. alt.)
COMPOSITAEGiseke (nom. cons.)
Sunflower or Aster Family
Dr. Avinash Gholave
Department of Botany
K.V. N. Naik Arts, Commerce and Science College Nashik.
agholave@gmail.com
3. Geographical distribution: Largest
family of flowering plants. It is
cosmopolitan and distributed almost
every corner of the world in every
habitat.
World: 1,528 genera and 23,840
species
India: 166 genera and 803 species
Maharashtra: 60 Genera and 143
Species
5. Habit: Herbs, shrubs, scandent shrubs
(Vernonia elaegnifolia) or trees (Vernonia
arborea, Leucomeris).
Root: Taproot and tuberous (Dahlia).
Stem: Erect or prostrate (Grangea), or
armed (Echinops) or glandular hairy and
winged (Sphaeranthus), or tuberous
(Helianthus tuberosus), or succulent
(Vernonia), or with milky latex (Sonchus),
or even reduced (Elaephantopus).
Vernonia arborea
Dahlia
Helianthus tuberosus Sonchus
Elaephantopus
Sphaeranthus
6. Leaves: Usually exstipulate,
alternate (Parthenium), or
opposite (Eclipta), or in
rosettes (Elaephantopus),
usually simple or pinnately
lobed (Dahlia) or lyrately
pinnatifid (Sonchus). Leaves
sometimes spinescent
(Echinops) or reduced to scales
(Haplophyllum).
Parthenium Eclipta
Elaephantopus
Dahlia
Sonchus Echinops
Haplophyllum
7. Plants gynomonoecious (with
bisexual disk florets and female ray
florets: (Helianthus), or monoecious
(only with bisexual disk florets:
Vernonia), or dioecious (only with
female ray florets: Dahlia).
Helianthus
Vernonia
Dahlia
8. Inflorescence: Capitulum, basically an
acropetal racemose inflorescence.
Capitulum is sometimes 1-flowered
(Echinops), or few-flowered
(Nanothamnus), or many-flowered
(Helianthus), usually subtended by an
involucre of 1-many whorls of free or
variously connate bracts, known as
phallaries.
Echinops Nanothamnus
Helianthus
9. Flower: Flowers bracteate (the bracts
forming an involucre in one to several
series), regular and irregular (often
combining central actinomorphic and
marginal ‘ray’ florets is zygomorphic).
Calyx: Sepals 2–30, of scales or bristles
constituting the ‘pappus’, 1 whorled,
usually adnate to ovary persistent with
valvate aestivation, calyx sometimes absent
(Ambrosia, Siegesbeckia).
10. Corolla: Petals 1–3 in ray florets and 4–5
in disk florets, gamopetalous, variously
coloured, with valvate aestivation. Corolla
is usually represented by one or two of the
three types:
• Tubular or Discoid Corolla:
Petals 5, with conspicuous tube and
short lobes with valvate aestivation.
• Ligulate or Ray Corolla: Petals 1-
3, represented by short teeths at tip
and a very short tube.
• Bilabiate corolla: Modified from a
tubular corolla and having a 3-
lobed upper lip and 2- lobed
usually slender, recurved lower lip.
Tubular
Ligulate
Bilabiate
11. Androecium: Stamens 3–5;
epipetalous, opposite to sepals and
alternate to petals, syngenesious. (In
ray floret absent). Anthers cohering
forming a tube or cylinder around
the style; basifixed; dehiscing by
longitudinal slits; usually
appendaged.
Gynoecium: Bicarpellary, syncarpous
unilocular, inferior ovary. Epigynous
disk usually present around the base
of the style. Styles 2; partially joined
stigmas 2. Ovules single in each
locule on basal placentation.
12. Pollination: Entomophilous. Pollination
mechanism conspicuously specialized via
stylar modification.
Fruit: cypsella.
Seed: Seeds non-endospermic.
Dispersal: Specialized by pappus calyx, which
show a parachute mechanism (wind dispersal)
but some time hooks or spines attach to cloths
and animal.
Floral formula:
Disc: Br ⊕ ♀ K (2–∞) C(4–5) A(4–5) G(2)
Ray: Br † ♀ K(4–5) C(3–5) A0 G(2)
13. • Usually herbaceous stem
• Leaves usually alternate
• Capitulum type of inflorescence surrounded by involucral bracts
(phyllaries)
• Calyx represented by pappus
• Stamens show syngeny; anthers united forming a cylinder
• Ovary inferior
• Fruit a cypsela and seeds non-endospermic
14. 1. Food:
Leaves of Lactuca sativa are used as salad. The roots of Helianthus tuberosus
are edible.
2. Oil:
The seeds of Helianthus and Artemisia yield oil.
3. Rubber:
It is obtained from Solidago laevenworthii and Taraxacum.
4. Insecticide:
The capitula of Chrysanthemum roseum and C. cinerriefolium are dried,
powdered and used as insecticide.
15. 5. Ornamental:
Zinnia, Dahila, Cosmos, Chrysanthemum, Calendula, Aster, Helianthus etc. are
well known garden plants.
6. Medicinal:
Artemisinin is isolated from the plant Artemisia annua and used against
malaria (for this work Tu Youyou and co-authors awarded Nobel Prize in
Medicine) and today this antimalarial drugs used for treatments of Covid-19.
The roots of Taraxacum used in bowel disorders.
The juice of Emillia sonchifolia leaves has cooling effect and is used in eye
inflammation and also for night blindness.
Eclipta alba used as tonic in spleen enlargement.
Centipeda orbicularis is used in cold and toothache.
16. Taxonomists have assigned different systematic position to the family.
Bentham and Hooker placed the family under Gamopetalae just after Rubiales.
Hutchinson did not treat the family as the last evolved and put the Asterales
under the 6th series far before the last series Laminales; but he placed it near
Rubiaceae.
Engler and Rendle placed it as the highest evolved dicot family. If
polyphyletic origin of the family is taken into account it may be assumed that the
origin of Rubiales and Asterales is from Apiaceae, which shows a tendency of
aggregation of flowers and reduction of calyx lobes, carpels and ovules.
Takhtajan traces the origin of Campanulales, Calycerales and Asterales
from the order Gentianales. He also relates Asteraceae with Calyceraceae and
other families of the other Campanulales.