Flower Anatomy

• Flower Anatomy
• A flower is the sexual reproductive organ in plants
• Flowers are often the most attractive structures of a plant

Flower Anatomy

• Sometimes known as a bloom or blossom
• Can be divided into these parts: calyx, corolla, androecium, and gynoecium

Common Flower Parts

• Stamen
• Anther
• Filament
• Petal
• Sepal
• Stigma
• Style Pistil
• Ovary

Calyx

• Collective term for all the sepals
• Primary task is to safeguard the flower while it is still in the bud process
• These are green petal-like structures located right above the base of the flower
• Peduncle is the stalk that holds the flower
• Receptacle is the enlarged tip of the pedicle

Corolla

• Collective colorful petals of the flower
• Petals are colorful leaf-like structures that occur in one or more circles within the sepals to attract pollinators

Stamen

• The essential male part of the flower consisting of an anther and filament
• Anther is where pollen grains are produced
• Filament is the slender stalk that supports the anther
• Collectively called the androecium

Pistil (Carpel)

• Seed-bearing organ of the flower
• Composed of the ovary, style, and stigma
• Collectively called the gynoecium
• Style – slender filament on top of which the stigma lies
• Stigma – sticky part found at the tip of the style to which pollen adheres after pollination
• Ovary is composed of the female gamete-containing ovules
• Ovules are the reproductive cells which will become the seed when fertilized by pollen

Classification of Flowers by Parts

• Complete – sepal, petal, stamen, pistil
• Incomplete – lacks either sepal, petal, stamen, pistil

Classification of Flowers by Symmetry

• Regular Flower/Actinomorphic – a radially symmetric flower
• Ex: Water Lily and Daisy
• Irregular Flower/Zygomorphic – a flower in which one or more members of a whorl differ in form from the others
• Ex: Pea Flower

Classification of Flowers by Sex

• Perfect Flower (Bisexual) – a flower showing both carpels and stamens
• Ex: Roses
• Imperfect Flower (Unisexual) – a flower with only one reproductive organ, either female or male
• Staminate – lacks pistils
• Pistillate – lacks stamens

Classification of Flowers by Composition

• Simple – a flower head made up of a few flowers
• Ex: Gumamela
• Compound – a flower head made up of many small flowers appearing as a single bloom
• Ex: Marigold

Pollination

• The transfer of pollen from a male reproductive structure (anther) to a female reproductive structure (stigma) by a vector such as wind or insects
• Self-Pollination – occurs when pollen grains are transferred to the stigma of the same flower or a different flower on the same plant
• Cross-Pollination – occurs when pollen grains are transferred to the stigma of different plants

Agents of Pollination

• Wind
• Water
• Insects
• Mammals
• Birds