🌿 Chapter Summary – Morphology of Flowering Plants

This chapter provides an in-depth understanding of the external structure (morphology) of flowering plants, explaining how plant organs are adapted for diverse functions.

🌱 The Root System

  • Roots arise from the radicle and anchor the plant to the soil.
  • Types: Taproot (dicots), Fibrous root (monocots), Adventitious roots.
  • Modifications: Storage (carrot), Prop (banyan), Stilt (maize), Pneumatophores (mangroves), Epiphytic (orchids).

🌿 The Stem

  • Develops from the plumule; supports branches, leaves, and flowers.
  • Modifications:
  • Underground: Rhizome, Tuber, Bulb, Corm.
  • Sub-aerial: Runner, Stolon, Sucker, Offset.
  • Aerial: Tendrils, Thorns, Phylloclade, Bulbil.

🍃 The Leaf

  • Arises from node, bears a bud in its axil.
  • Types: Simple (mango), Compound (neem, silk cotton).
  • Venation: Reticulate (dicots), Parallel (monocots).
  • Phyllotaxy: Alternate (sunflower), Opposite (guava), Whorled (alstonia).

🌸 Inflorescence

  • Racemose: Indefinite growth, acropetal succession (Mustard).
  • Cymose: Definite growth, basipetal succession (Jasmine).
  • Special types: Cyathium (Euphorbia), Hypanthodium (Ficus), Verticillaster (Ocimum).

🌺 The Flower

  • Reproductive unit of angiosperms.
  • Four whorls: Calyx, Corolla, Androecium, Gynoecium.
  • Aestivation: Valvate, Twisted, Imbricate, Vexillary.
  • Placentation: Marginal, Axile, Parietal, Free-central, Basal.

🍎 Fruit and Seed

  • Fruit: Mature ovary; may be true or false. Types – Simple, Aggregate, Multiple.
  • Seed: Mature ovule with embryo and stored food. Dicot (Pea) – two cotyledons; Monocot (Maize) – one cotyledon.

🌼 Floral Formula and Diagram

  • Symbolic representation of floral structure.
  • Fabaceae: % ⚥ K(5) C(1+2+(2)) A(9)+1 G₁
  • Solanaceae: ✳ ⚥ K(5) C(5) A5 G(2)
  • Liliaceae: ✳ ⚥ P(3+3) A(3+3) G(3)

🧭 Key Concepts to Remember

  • Morphology: Study of external form and structure.
  • Epiphytic roots: Absorb moisture (Vanda).
  • Phylloclade: Photosynthetic stem (Opuntia).
  • Papilionaceous corolla: Characteristic of Fabaceae.
  • Parthenocarpy: Fruit without fertilization (Banana).
  • Basipetal order: Oldest flower at top (Cymose).
  • Acropetal order: Oldest flower at base (Racemose).
  • Free-central placentation: Ovules on central column (Dianthus).
  • False fruit: Develops from thalamus (Apple).
  • Diadelphous stamens: (9+1) in Pea.
  • Superior ovary: Ovary above other floral whorls (Mustard).
  • Parallel venation: Found in monocots (Maize).
  • Reticulate venation: Found in dicots (Mango).

🎯 Exam Tips for NEET & IAT

🌱 Root System

  • Pneumatophores → respiration in mangroves (Rhizophora).
  • Prop roots → support in banyan.
  • Stilt roots → maize & sugarcane.

🌿 Stem Modifications

  • Rhizome: Ginger – vegetative propagation.
  • Tuber: Potato – eyes = axillary buds.
  • Bulb: Onion – storage.
  • Corm: Colocasia – solid stem.
  • Phylloclade: Opuntia – photosynthetic stem in deserts.

🍃 Leaf

  • Alternate phyllotaxy → Sunflower.
  • Opposite phyllotaxy → Guava.
  • Whorled → Alstonia.
  • Reticulate venation → Dicots; Parallel → Monocots.

🌸 Flower & Inflorescence

  • Racemose – main axis grows indefinitely (Mustard).
  • Cymose – main axis terminates in flower (Jasmine).
  • Twisted aestivation → Hibiscus; Vexillary → Pea.
  • Axile placentation → Lemon; Marginal → Pea.

🍎 Fruit & Seed

  • True fruit → from ovary (Mango).
  • False fruit → from thalamus (Apple).
  • Endospermic seed → Monocots; Non-endospermic → Dicots.
  • Parthenocarpy → Banana.

🌼 Floral Families

  • Fabaceae: Zygomorphic, diadelphous, legume fruit.
  • Solanaceae: Actinomorphic, epipetalous stamens, berry/capsule fruit.
  • Liliaceae: Monocot, trimerous flowers, axile placentation.

🧠 NEET/IAT Focus Areas

  • Root & stem modifications – 2–3 questions.
  • Floral formula interpretation – 1–2 questions.
  • Families (Fabaceae, Solanaceae, Liliaceae) – 3+ questions almost every year.
  • Terms like aestivation, placentation, phyllotaxy are frequent one-liners.