Family -Asteraceae or Compositae

🌼 Asteraceae or Compositae: The Largest Family of Flowering Plants

The Asteraceae or Compositae family, commonly known as the Sunflower family, is one of the most widespread and diverse plant families on Earth. It comprises nearly 950 genera and over 20,000 species, making it the largest family of flowering plants. In India alone, about 697 species from this family are found. These plants thrive in diverse habitats and are especially abundant in temperate regions.

🔬 Scientific Classification of Asteraceae or Compositae

• Kingdom: Plantae
• Division: Magnoliophyta (Angiosperms)
• Class: Magnoliopsida (Dicots)
• Order: Asterales
• Family: Asteraceae (or Compositae)

🌱 Morphological Features of Asteraceae

🔹 Habit

Most members of the Asteraceae or Compositae family are annual or perennial herbs, such as Helianthus annuus (sunflower), Tagetes erecta (marigold), and Chrysanthemum spp.
A few, like Vernonia arborea, are small shrubs. Aquatic herbs such as Cacsulia axillaris also belong to this family.

🔹 Root

Generally, a taproot system is present. In plants like Dahlia, roots become tuberous.
Helianthus tuberosus forms edible underground tubers rich in inulin, a carbohydrate beneficial for health.

🔹 Stem

Stems are mostly erect, herbaceous, solid, and cylindrical. In Helianthus tuberosus, the stem is tuberous and underground. Some genera produce milky latex, a common trait in this family.

🔹 Leaves

Leaves are typically alternate but may also be opposite or whorled. They are simple or compound, with reticulate venation.
In some genera, like Relhania, leaves are needle-like, while others, such as Corymbium, exhibit parallel venation.

🌼 Inflorescence: The Capitulum

The most distinctive feature of the Asteraceae or Compositae family is its unique inflorescence, known as the capitulum or head. It consists of numerous small flowers (florets) crowded together on a receptacle, surrounded by involucral bracts.

Two types of florets are usually found:

• Ray florets: Peripheral, ligulate, often sterile or pistillate
• Disc florets: Central, tubular, bisexual

🌸 Types of Flower Heads

1. Homogamous heads: All florets are of one type, either tubular (Ageratum) or ligulate (Sonchus).
2. Heterogamous heads: Both ray and disc florets present, e.g., Helianthus annuus.

🔍 Floral Structure of Asteraceae

• Calyx: Modified into pappus (hairs or bristles), aiding in seed dispersal.
• Corolla: Generally 5-lobed and gamopetalous; may be tubular, ligulate, or bilabiate.
• Androecium: 5 stamens with united anthers (syngenesious), filaments free.
• Gynoecium: Bicarpellary, inferior ovary, unilocular with basal placentation.
• Fruit: Cypsela, often with a hairy pappus.
• Seed: Exalbuminous (lacking endosperm).

🌻 Example Species and Their Description

✅ 1. Helianthus annuus (Sunflower)

• Habit: Annual herb
• Inflorescence: Large, flat capitulum
• Ray florets: Ligulate, sterile or pistillate
• Disc florets: Tubular, bisexual
• Fruit: Cypsela
• Uses: Ornamental, oil production, heart-healthy edible seeds

✅ 2. Tridax procumbens (Coat Button)

• Habit: Creeping herb
• Leaves: Opposite, hairy, ovate
• Inflorescence: Small capitulum
• Ray florets: Ligulate, pistillate
• Disc florets: Tubular, bisexual
• Uses: Traditional medicine for wound healing

💡 Economic Importance of Asteraceae or Compositae

🌿 Medicinal & Edible Plants

1. Sunflower (Helianthus annuus) – Edible oil used for cooking and health.
2. Jerusalem Artichoke (H. tuberosus) – Edible tubers rich in inulin.
3. Safflower (Carthamus tinctorius) – Oil used medicinally for arthritis.
4. Lettuce (Lactuca sativa) – Popular salad green.
5. Chicory (Chicorium intybus) – Roots used in coffee substitutes.
6. Eclipta alba – Leaves yield Bhringraj hair oil.
7. Arnica montana – Flowers used in Arnica medicine.
8. Grindelia camporum – Used to treat respiratory problems.
9. Tussilago farfara – Leaves used for cold, cough, asthma.

🌸 Ornamental Plants

• Tagetes erecta – Marigold, source of natural yellow dye.
• Zinnia elegans – Zinnia, vibrant garden flower.
• Calendula officinalis – Pot marigold, ornamental and medicinal.
• Dahlia pinnata – Garden dahlia, famous for tuberous roots.
• Cosmos bipinnatus – Cosmos, delicate ornamental.
• Chrysanthemum spp. – Used in decorations and ceremonies.
• Aster amellus – Border plant in gardens.

Read Also: Family –Rubiaceae

🌍 Conclusion

The Asteraceae or Compositae family is a true marvel of plant evolution, combining botanical beauty, ecological adaptability, and economic value. From sunflowers and marigolds to lettuce and chicory, the family enriches our diets, gardens, and health systems. Understanding this family not only aids in plant taxonomy but also opens doors to agricultural, medicinal, and ornamental uses.