Bract

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Castilleja levisecta bracts

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Banana bract

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Bracts are modified or specialized leaves, often associated with reproductive structures such as flowers, inflorescences, or cones. Their primary function is not photosynthesis but rather to attract pollinators or protect the developing flowers or fruit. Bracts can be highly conspicuous, such as those seen in the Poinsettia plant, where the bright red bracts are often mistaken for flower petals, or they can be more subdued and green, blending in with the foliage.

Characteristics

Bracts vary widely in shape, size, and color, reflecting their diverse roles in plant reproduction and survival. Some common characteristics include:

• Coloration: Bracts can be brightly colored to attract pollinators. This is especially evident in species where the true flowers are small and not visually striking.
• Shape and Size: The shape and size of bracts can be highly variable, from large and leaf-like to small and scale-like, depending on their function and the plant species.
• Position: Bracts are typically located at the base of a flower or flower cluster, but their position can vary. In some plants, bracts are arranged in a spiral on an inflorescence stalk, while in others, they may encase the flower or fruit completely.

Functions

The functions of bracts are diverse and include:

• Attraction of Pollinators: Brightly colored bracts can serve to attract pollinators to the flowers, which may be less conspicuous.
• Protection: Bracts can protect developing flowers or fruit from herbivores and harsh environmental conditions.
• Support: In some plants, bracts may provide support to flowers or inflorescences, helping to maintain their position for optimal pollination.

Examples

Some notable examples of plants with prominent bracts include:

• Poinsettia: Known for its bright red bracts that are often mistaken for flower petals around the Christmas season.
• Bougainvillea: Features colorful bracts surrounding small, white flowers, giving the plant its vibrant appearance.
• Corn: The husks that enclose the ear are actually large, leafy bracts that protect the developing kernels.

Ecological and Evolutionary Significance

Bracts play a significant role in the ecology and evolution of flowering plants. Their ability to attract pollinators and protect reproductive structures can significantly influence reproductive success. The variation in bract form and function across different plant species reflects the diverse evolutionary strategies plants have developed to ensure pollination and seed dispersal.

See Also

• Leaf
• Flower
• Pollination
• Seed dispersal