Bract (botany): modified leaves associated with flowers and inflorescences

Forms and morphology

Bracts vary widely among plant groups. Some are small and scale-like while others are large, showy and petal-like. Specialized terms describe these variations: bracteoles (small bracts on individual flower stalks), involucres (a group of bracts forming a cup or ring around a cluster), and spathes (a large, often sheathing bract found in families like Araceae). Their surfaces may be thin and papery, fleshy, hairy, or pigmented.

• Bracteole: secondary, often tiny bract on the pedicel.
• Involucre: whorl or cluster of bracts beneath an inflorescence.
• Spathes: large bracts that enclose or subtend flowers (e.g., calla lily).

Functions and ecological roles

Bracts perform several functions beyond simple support. They can protect developing buds from herbivores and weather, help direct pollinators by providing visual or tactile cues, and sometimes aid in seed dispersal. In some species, brightly colored bracts take over the role of petals to attract pollinators, while true petals are reduced or absent.

• Protection: shielding buds and young flowers.
• Attraction: colorful bracts that mimic petals.
• Support and thermoregulation: sheltering reproductive organs.

Examples, uses and identification

Familiar examples include the red bracts of poinsettias and the papery bracts of bougainvillea, both of which are commonly mistaken for petals. Dogwood trees have prominent bracts surrounding small flower clusters, and grasses sometimes have bracts called glumes. Horticulturists and botanists use bract characteristics to identify species and cultivars because bracts can be consistent diagnostic features. In landscaping and floral design, showy bracts are valued for seasonal color and texture.

Distinctions and notes

When identifying or describing plant structures, it is important to distinguish bracts from true floral organs. Bracts are modified leaves and arise from vegetative nodes, whereas petals and sepals are parts of the flower itself. Terminology can overlap in common usage, so careful morphological observation or microscopic study may be necessary for precise classification.

For further reading on related botanical terms and examples, consult general botany resources or floras that detail floral morphology and inflorescence types.