2.1 Morphology of Flowering Plants

The Root

  • Regions: Root Cap, Meristematic Activity, Elongation, Maturation.
  • Types:
    • Tap Root: Dicotyledonous plants (e.g., Mustard).
    • Fibrous Root: Monocotyledonous plants (e.g., Wheat).
    • Adventitious Root: Arise from parts other than the radicle (e.g., Banyan).
  • Modifications:
    • Storage: Carrot, Radish, Sweet Potato.
    • Support: Prop roots (Banyan), Stilt roots (Maize).
    • Respiration: Pneumatophores (Rhizophora).

The Stem

  • Features: Nodes, Internodes, Buds.
  • Modifications:
    • Underground: Tuber (Potato), Rhizome (Ginger), Corm (Colocasia).
    • Sub-aerial: Runner (Grass), Stolon (Strawberry), Sucker (Banana), Offset (Pistia).
    • Aerial: Tendrils (Gourds), Thorns (Citrus), Phylloclade (Opuntia), Cladode (Asparagus).

The Leaf

  • Parts: Leaf Base, Petiole, Lamina.
  • Venation: Reticulate (Dicots), Parallel (Monocots).
  • Types: Simple, Compound (Pinnately, Palmately).
  • Phyllotaxy: Alternate, Opposite, Whorled.
  • Modifications: Tendrils (Peas), Spines (Cacti), Storage (Onion), Insectivorous (Pitcher Plant).

Inflorescence

  • Definition: The arrangement of flowers on the floral axis.
  • Types:
    • Racemose: Main axis continues to grow; acropetal succession.
    • Cymose: Main axis terminates in a flower; basipetal succession.

The Flower

  • Structure: Calyx (sepals), Corolla (petals), Androecium (stamens), Gynoecium (carpels).
  • Symmetry: Actinomorphic (radial), Zygomorphic (bilateral).
  • Aestivation: Valvate, Twisted, Imbricate, Vexillary.
  • Androecium: Monadelphous, Diadelphous, Polyadelphous.
  • Gynoecium: Apocarpous, Syncarpous; Superior, Half-inferior, Inferior ovary.

Placentation

  • Definition: The arrangement of ovules within the ovary.
  • Types:
    • Marginal: Pea
    • Axile: Tomato, Lemon
    • Parietal: Mustard
    • Free Central: Dianthus
    • Basal: Sunflower

Floral Formula

  • A concise representation of a flower's structure using symbols.
  • Example (Mustard):
    Ebr ⊕ ⚥ K₂₊₂ C₄ A₂₊₄ G₍₂₎