Flower Anatomy and Pollination

Position of Flower Parts

  • Understanding flower anatomy is essential for identifying the position of flower parts relative to the ovary.

Types of Ovaries

  • Superior Ovary (Hypogynous):

    • Definition: Ovary is located above the other flower parts.
    • Flower parts attach below the ovary.
    • Interchangeable terms: Superior ovary and hypogynous.

  • Perigynous Ovary:

    • Definition: Ovary is at the center with flower parts attaching around its midline.
    • The receptacle wraps halfway around the ovary.

  • Inferior Ovary (Epigynous):

    • Definition: Ovary is located below the other flower parts.
    • Flower parts attach above the ovary.
    • Interchangeable terms: Inferior ovary and epigynous.

Visual Diagram Analysis

  • Diagrams help in visualizing the positions and relationships of flower parts:
    • Superior Ovary: Filaments, petals, and sepals attach below the ovary.
    • Inferior Ovary: Filaments, petals, and sepals attach at the upper edge of the ovary.
    • Perigynous: Attachments are aligned along the midline, clearly wrapping around the ovary.

Carpel Variations

  • Definition: Carpels are the ovary chambers within flowers.
  • Types of carpels:
    • Single Carpel: Singular ovary chamber.
    • Free Carpels: Non-joined, appearing as multiple individual chambers.
    • Example: Five free carpels resemble stacked bottles.
    • United Carpels: Joined carpels that share a common chamber.
    • Example: Two united carpels show no complete wall between them.
    • To distinguish between free and united carpels:
    • Look for complete chamber walls in free carpels and lack thereof in united carpels.

Observational Techniques

  • To study flower morphology:
    • Cross-sections are essential to identify carpel variations.
    • Larger fruits (such as tomatoes) can provide clearer visuals than tiny flowers, which may require a microscope.

Pollination and Ovarian Development

  • Pollination is crucial for fertilization:
    • Example: A bee collecting pollen can transport it to another flower.

Sample Structures

  • Rose Hip:
    • Cross-section reveals a large swollen ovary with seeds forming.
    • Displays an inferior (hyogynous) ovary with filaments, petals, and sepals attaching at the top.