Family: Compositate (Asteraceae)



This is the largest family of the angiosperm and includes about 1528 genera and 22750 species.In Nepal, it represents 104 genera and 428 species.

  1. Distribution:
    The members of the family are found all over the worls(cosmopolotian), most of them are found in the tropical regions.
  2. Habit and Habitat:
    Annual or perenneal herbs or under shrubs or shrubs, rarely trees or climbers. Many are xerophytes or mesophytes, a few are aquatic.
  3. Root:
    Usually, tap and branched, sometimes adventitious. In Helianthus, the roots are modified into tubers.
  4. Stem:
    Erect or postulate, rarely climbing, herbaceous or woody, solid or fistular, sometimes spiny e.g. Sonchus, sometimes modified into tuber e.g. Helianthus, some contains latex e.g. Sonchus or oil glands.
  5. Leaf:
    Radical, cauline or ramal, usually alternate, sometimes opposite and rarely whorled, simple or compound, estipulate, glabrous or hairy; entire or serrate or lobbed, apex  acute or obtuse, reticulate venation.
  6. Inflorescene:
    Racemose, head or capitulum with an involucres of bracts; rarely in spike.
  7. Flower:
    Sessible, bracteable or ebracteate, two kinds of flowers are found in inflorescence, towards the center are tubular flowers called disc florets and towards the periphery of captulum are liguate flowers called ray florets.

    • Ray florets: Sessile, bracteates or ebracteate, ireegular or zyomorphic, ligulate, incomplete, unisexual or neuter, pentamerous, epigynous.
      • Calyx: Sepals-2-5, represented by scales or hairy, pappus, velvate, superior.
      • Corolla: Petals-3, gamopetalous, ligulate, velsate superior.
      • Androecium: Absent
      • Gynoecium: Bicapellary, sycarpous, ovary inferior, unilocular containing a single anatropous ovule, basal placentation,  style long and slender, stigma bifid.
    • Disc floret: Sessile, bracteate or ebracteate, actinnomoprphic, incomplete or complete, bisexual, pentamenous, tubular, epigynous.
      • Calyx: Sepals-2-5, represented by scale or hairy peppus, aestiration, superior.
      • Corolla: Petals-5, gamopetalous, tubular, actinomorphic, valvare aestivation, superior
      • Androecium: Stamen-5, syngenesious epipetalous, anthers bicelled, basified, introse, supenor
      • Gynoecium: As in ray floret i.e. bicapellary, syncarpous, ovary inferior, unilocular containing a single anatropous ovule, basal placentation, style long and slender, Stigma bifid.
  8. Fruit: Cypselu
  9. Seed: Exalbuminous
  10. Classification:
    Kingdom:               Plantae
    Sub-kingdom:        Phanerogamae
    Division:                Angiospermae
    Class:                     Dicotyledoneae
    Sub-class:              Garropetalae
    Series:                   Inferae
    Order:                   Asterobs
    Family:                  Compositae (Asteraceae)
  11. Economically important plants:
    Helianthus annus (sunflower) :     oil yielding
    Tagetes patula (Mangold):           medicinal plants
    Lactuca satira (Lettuce):               vegetable
    Dahlia variabillis               :           ornamental

Diagnostic features of family Compositae (Asternaceae):

  1. Stem: hairy and with latex or oil ducts
  2. Inflorescene: head or capitulum having involucres of bract
  3. Flowers: Sessile called florets, two types of flowers ; ray florets and disc florets
  4. Florets: tubular or ligulate, epigynous
  5. Calyx: represented by sales, bristles or pappus
  6. Corolla: 3-5, gemopetalous, toothed
  7. Stamens: -5, syngenesioud and epipetalous in disc floret
  8. Gynociem: bicapilarry, ovary inferior, based placentation
  9. Fruit: Cypsela

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