Visual Description
Petals are the colorful, often fragrant parts of a flower that most people think of when they imagine "the flower." They form the inner ring of the flower, surrounding the reproductive organs (stamens and pistils).
Key Features
- Colorful: Usually bright colors (yellow, pink, red, white, purple)
- Delicate texture: Softer than leaves, often velvety or papery
- Arranged in a ring: Form the corolla (collective term for all petals)
- Variable number: Can range from 3-4 to dozens or even hundreds
- Often scented: Many produce fragrances to attract pollinators
Why Petals Exist
Petals evolved with one primary purpose: attract pollinators.
Functions:
- Visual signals: Bright colors guide pollinators from a distance
- Landing platforms: Provide a place for insects and birds to land
- Nectar guides: Often have lines or patterns (visible in UV) directing pollinators to nectar
- Protection: Shield reproductive organs from rain and damage
- Rewards: Some petals themselves contain oils or scents pollinators harvest
How to Identify
Petal vs. Sepal
Many people confuse petals with sepals:
- Petals: Colorful, inner ring, attract pollinators
- Sepals: Usually green, outer ring, protect bud
Trick: Sepals are what you see BEFORE the flower opens. Petals are what opens UP from inside.
Petal Count Matters
Petal number can help identify plant families:
- 3 or 6 petals: Often monocots (palms, lilies)
- 4 petals: Crucifers (mustard family)
- 5 petals: Very common in many families (roses, legumes)
- Many petals: Magnolias, water lilies
Petal Fusion
Free petals (polypetalous):
- Each petal separate
- Example: Rose, Buttercup
Fused petals (sympetalous):
- Petals joined into tube or trumpet
- Example: Morning glory, Trumpet tree
Identification Tip
When identifying trees by flowers, note:
- Number of petals: Count carefully (may need magnifier)
- Color and pattern: Document color accurately
- Shape: Rounded, pointed, notched?
- Size: Measure largest petal
- Fusion: Are petals separate or joined?
- Persistence: Do they fall quickly or stay on tree?
Examples in Costa Rica
Spectacular Petal Displays:
Yellow Petals:
- Corteza Amarilla (Handroanthus ochraceus): 5 large yellow petals, trumpet-shaped
- Guayacán Real (Guaiacum sanctum): 5 blue-purple petals (rare color!)
Pink/Purple Petals:
- Roble de Sabana (Tabebuia rosea): 5 pink petals, showy spring display
- Jacaranda: Tubular purple flowers with 5 petal lobes
White Petals:
- Madero Negro (Gliricidia sepium): Pink-purple pea-like flowers
- Jiñocuave: Small white fragrant flowers
No True Petals:
- Figs (Ficus spp.): Flowers hidden inside fruit
- Many wind-pollinated trees: Reduced or absent petals
Ecological Importance
Pollinator Partnerships
Different petal characteristics attract different pollinators:
Hummingbirds:
- Red, orange, or pink petals
- Tubular shape
- No scent needed
- Example: Many Erythrina species
Bees:
- Blue, purple, yellow, white
- Landing platform shape
- Often scented
- UV patterns (invisible to humans)
Moths:
- White or pale colors
- Strong nighttime fragrance
- Open at dusk
- Example: Night-blooming jasmine
Bats:
- Large, sturdy petals
- White or pale colors
- Strong fermented/musky scent
- Open at night
Seasonal Displays
In Costa Rica's tropical dry forest, many trees produce flowers during the dry season (December-April) when leaves have fallen:
- Why? Better visibility for pollinators
- Result: Spectacular color displays on bare branches
- Examples: Tabebuia species create massive yellow and pink clouds
Petal Modifications
Not all petals are simple flat structures:
Spurs:
- Long tubular extensions
- Store nectar at base
- Example: Orchids, Columbine
Pouches:
- Trap pollinators temporarily
- Ensure pollen transfer
- Example: Lady's slipper orchids
Mimicry:
- Some petals mimic other structures
- Example: Orchids that look like female bees or wasps
Cultural Significance
Traditional Uses
Medicinal:
- Flower petals often used in herbal remedies
- May contain beneficial compounds
- Example: Hibiscus petals for tea
Ceremonial:
- Flower petals used in festivals and celebrations
- Religious offerings
- Wedding decorations
Culinary:
- Some tree flower petals are edible
- Used in salads, teas, garnishes
- Example: Squash blossoms (though not from trees)
Conservation Note
Petal color changes can indicate environmental stress:
- Pollution may alter petal colors
- Climate change affects flowering timing
- Loss of pollinators means petals evolve differently
Related Concepts
- Corolla: The collective term for all petals of a flower
- Perianth: Combined term for petals + sepals
- Tepals: When petals and sepals look identical (like magnolias)
- Nectary: Special structures (often on petals) that produce nectar
- Pollination syndrome: The set of flower traits (including petal shape/color) that attract specific pollinators