What Are the Functions of Flower Bracts?

Overview

Many perennials we grow in our gardens have "insignificant inflorescence," or tiny flowers that grow in a center surrounded by modified leaves called "bracts." Often we grow a plant not for its flowers but for its bracts.

Protection

The primary task of a bract is to protect the inflorescence. Some, like the stinking passionflower, exude a substance that repels grazers. Others have bristles. They may look like a leaf, part of a flower or, like Euphorbia (spurge), part of the plant.

Shelter

A large, often graceful bract known as a spathe surrounds or encloses a flower cluster, or spadix, in calla lilies, jack-in-the-pulpits and peace lilies.

Attraction

Large or colorful bracts surround flowers to bring their attention to specific insects. Poinsettias and sunflowers have bracts that signal pollinators with bright colors or provocative (to bugs) shapes.

Recyling

The stiff bracts on strawflowers and paper daisies are actually dead tissue reused to surround flowers. They often remain long after the seeds have dispersed and are used as dried flowers.

Imitation

Bracts may imitate the sepals, or calyx, of a flower. In carnations and hibiscus, this adds strength to areas surrounding the ovule, the part of the flower where seeds develop.

References

  • Stinking Passionflower
  • American Naturalist Magazine Highlights

Who Can Help

  • Bio-Medicine: Definitions
  • Large-bract Plantain
Keywords: perennials, bracts, flowers, inflorescence, gardens

About this Author

Laura Reynolds began writing professionally in 1974. She has worked as author and editor in nonfiction, professional journals and newspapers. Reynolds has also served in numerous appointed and elected local offices. She holds a Bachelor of Science in education from Northern Illinois University.