Study Notes on Flower Anatomy and Reproduction

Flower Overview

• Kvet (Flos) is the reproductive organ of plants responsible for forming sex cells, essential for reproduction and species preservation.

• A group of flowers on a common stem is called an inflorescence.

Functions of Flower

• Pollination: Achieved through placement, color, or structure, involving wind or insects.

  • Self-pollination: Pollination with own pollen.

  • Cross-pollination: Pollination with pollen from another flower.

• Protection: Safeguards reproductive organs (stamens and pistils) and stored sex cells.

• Development: Facilitates seed development.

Structure of the Flower

1. Flower Stem: Attaches the flower to the stem.

2. Receptacle: Enlarged top part of the flower stem, where glands secrete nectar.

3. Flower Parts: Consists of sepals (calyx), petals (corolla), and possibly tepals.

4. Stamens: Male part producing pollen grains.

5. Pistil: Female reproductive organ formed by the fusion of one or more carpels.

Structure of the Pistil

• Stigma: Top part where pollen grains adhere.

• Style: Elongated tubular middle part.

• Ovary: Bottom expanded section containing one or more ovules.

Structure of the Stamens

• Result from the modification of leaves.

• Gymnosperms: Flat or scale-like with many pollen sacs.

• Angiosperms: Divided into anther (where pollen grains are) and filament.

Flower Coverings

• Divided into colorful parts that do not directly participate in reproduction:

  • Calyx: Outermost green part protecting the flower.

  • Corolla: Inner, often colorful part.

  • Flowers with undifferentiated coverings are called tepals.

Gender Classification of Flowers

• Perfect Flowers: Contain both stamens and pistils (e.g., apple).

• Imperfect Flowers: Contain only stamens or pistils.

• Monoecious Plants: Both flower types on one plant (e.g., oak).

• Dioecious Plants: One individual has only one gender of flowers (e.g., willow).