Plant Biology: Flower Structure and Leaf Morphology

Basic Parts:
- Sepals: Protect the flower bud; often green.
- Petals: Attract pollinators; usually colorful.
- Stamens: Male reproductive part; consists of anther (produces pollen) and filament.
- Pistil: Female reproductive part; contains stigma (receives pollen), style (connects stigma to ovary), and ovary (contains ovules).
Types of Flowers:
- Complete Flowers: Have all four main parts (sepals, petals, stamens, pistils).
- Incomplete Flowers: Lack one or more main parts.
- Perfect Flowers: Contain both stamens and pistils.
- Imperfect Flowers: Either male (staminate) or female (pistillate).

Basic Structure:
- Blade (Lamina): Flat part of the leaf; where photosynthesis occurs.
- Petiole: Stalk that attaches the leaf to the stem.
- Stipules: Small leaf-like structures at the base of the petiole.
Types of Leaves:
- Simple Leaves: Single undivided blade.
- Compound Leaves: Divided into smaller leaflets.
- Modified Leaves: Adapted for specific functions (e.g., tendrils, spines).
Leaf Arrangement:
- Alternate: Leaves arranged singly at different heights along the stem.
- Opposite: Two leaves arise at the same level on opposite sides of the stem.
- Whorled: Three or more leaves grow from a single node.

Types of Stems:
- Herbaceous Stems: Soft, green; typically non-woody.
- Woody Stems: Hard, thick; provide structural support.
Functions:
- Support leaves and flowers.
- Transport water, nutrients, and photosynthetic products.
- Store nutrients in some species.
Adaptations:
- Succulent Stems: Store water (e.g., cacti).
- Climbing Stems: Tendrils allow plants to cling and support (e.g., peas).
- Thorns and Spines: Defense mechanisms against herbivores.

Types of Root Systems:
- Taproot System: One main root (taproot) with smaller lateral roots (e.g., carrots).
- Fibrous Root System: Many thin roots emerging from the base of the stem (e.g., grasses).
Functions:
- Anchor the plant in the soil.
- Absorb water and nutrients from the soil.
- Store energy and nutrients in some species.
Adaptations:
- Aerial Roots: Grow above ground for support or moisture absorption (e.g., orchids).
- Prop Roots: Provide additional support (e.g., corn).
- Storage Roots: Store carbohydrates and nutrients (e.g., sweet potatoes).

Pollination Strategies:
- Biotic Pollination: Involves animals (insects, birds) to transfer pollen.
- Abiotic Pollination: Wind or water aids in pollen distribution.
Fertilization:
- Occurs when pollen unites with ovules in the ovary, leading to seed development.
Seed Dispersal Mechanisms:
- Wind: Lightweight seeds can be carried by wind (e.g., dandelions).
- Water: Seeds that float can disperse via water (e.g., coconuts).
- Animal: Seeds can attach to fur or be ingested and excreted (e.g., berries).
Fruit Types:
- Fleshy Fruits: Attract animals for seed dispersal (e.g., apples).
- Dry Fruits: Can be dehiscent (split open) or indehiscent (do not split) (e.g., nuts).

Sepals: Protect flower buds and are typically green.
Petals: Brightly colored to attract pollinators.
Stamens: Male components that include the anther, producing pollen, and the filament.
Pistil: Female components including stigma (where pollen lands), style (connects stigma to ovary), and ovary (contains ovules).
Complete Flowers: Have all four main floral parts (sepals, petals, stamens, pistils).
Incomplete Flowers: Lack one or more of the main floral parts.
Perfect Flowers: Contain both stamens and pistils.
Imperfect Flowers: Either only male (staminate) or only female (pistillate).

Blade (Lamina): The flat area where photosynthesis primarily occurs.
Petiole: The stalk connecting the leaf blade to the stem.
Stipules: Small leaf-like structures located at the base of the petiole.
Simple Leaves: Feature a single, undivided blade.
Compound Leaves: Composed of smaller leaflets.
Modified Leaves: Adaptations for particular functions, such as tendrils or spines.
Leaf Arrangement:
- Alternate: Leaves are arranged singly at various heights along the stem.
- Opposite: Two leaves are positioned at the same level on opposite sides.
- Whorled: Three or more leaves originate from a single node.

Herbaceous Stems: Soft and green, typically non-woody.
Woody Stems: Hard and thick, providing structural support for the plant.
Functions: Support the plant structures, transport water and nutrients, and store nutrients in some species.
Adaptations:
- Succulent Stems: Designed to store water, commonly found in cacti.
- Climbing Stems: Equipped with tendrils for support, such as in peas.
- Thorns and Spines: Serve as protective mechanisms against herbivores.

Taproot System: Contains a primary taproot and smaller lateral roots, found in plants like carrots.
Fibrous Root System: Composed of numerous thin roots emerging from the base, typical in grasses.
Functions: Anchor the plant, absorb water and nutrients, and store energy and nutrients in certain species.
Adaptations:
- Aerial Roots: Grow above the soil for support or moisture absorption, e.g., in orchids.
- Prop Roots: Offer additional stability, as seen in corn.
- Storage Roots: Store carbohydrates and nutrients, such as in sweet potatoes.

Pollination Strategies:
- Biotic Pollination: Relies on animals like insects or birds for pollen transfer.
- Abiotic Pollination: Utilizes wind or water for pollen distribution.
Fertilization: Occurs when pollen unites with ovules in the ovary, initiating seed development.
Seed Dispersal Mechanisms:
- Wind: Lightweight seeds can be carried by air currents, exemplified by dandelions.
- Water: Floating seeds can move via water, as observed in coconuts.
- Animal: Seeds may attach to fur or be dispersed through animal excretion, such as berries.
Fruit Types:
- Fleshy Fruits: Encourage animal consumption for seed dispersal, like apples.
- Dry Fruits: Can be dehiscent (split open) or indehiscent (remain intact), as seen in nuts.