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Parts of a Composite Flower

By Sophie Johnson ; Updated September 21, 2017
A composite flower lives by the motto E pluribus unum: "Out of many, one."

At first glance, a composite flower like the daisy looks simple, with petals forming rays around a colorful disk. Upon closer inspection, however, these flowers aren't simple at all. The flower is actually made up of many flowers--inflorescences--masquerading as a single flower. Each "petal" is a flower, as is each bump on the disk. Other examples of composite flowers are sunflowers, chrysanthemums, dandelions and zinnias.

Ray Flowers

A field of the composite flower dandelion, each boasting many yellow ray flowers.

On a composite flower, what look to be petals radiating from the center in spoke-like fashion are individual blooms called ray flowers. They are sometimes described as "ligulate," which refers to their strap-like shape. Some composite flowers--the dandelion and chrysanthemum, for instance--only possess ray flowers. Composites like the sunflower also include disk flowers found at the center.

Disk Flowers

No rays flowers soften this composite, with tiny disk flowers peeping out amid spine-like growths.

The location of disk flowers are easy to spot in the center of a composite flower such as aster; the ray flowers point inward to where disk flowers are packed together. Some composites, though, only possess disk flowers. These include thistles and burdock. Each disk flower produces one seed and is either female or a hermaphrodite with both male and female parts. Disk flowers tend to be shaped like tubes.


Stamens are one of the four major flower parts along with pistils, petals and sepals. Stamens are the male parts in flowers that have them, producing sperm in rounded lobes called anthers. In composite flowers, often the anthers fuse together to form a ring around the female pistil.


Pistils arise from tubal disk flowers.

The female flower parts are called carpels, often fused into a single pistil that's found at the center of any flower that possesses them, including disk flowers. In composite flowers, the pistil's style--a stalk connecting the pistil's ovary and stigma--rises up in the middle of the ring of stamens. The fruits of a composite flower are called achenes. This includes fruit from the sunflower, which in everyday parlance are known simply as sunflower seeds.


A child helps a dandelion spread its seed.

On a flower, sepals are accessory parts--that is, they aren't directly involved in reproduction. They are usually leaf like, though in composite flowers, they are transformed to something more akin to scales, or into what are termed pappuses, which look like hairs, threads, bristles or even barbs. Pappuses can help with seed dispersal. Barbs, for instance, hook into animals, carrying seed. Children often blow dandelion pappuses, sending the seeds floating away.


What look like prominent green sepals protecting an opening sunflower are actually bracts.

Bracts, like sepals, are leaf-like growths. They may look like sepals, petals, scales or not be there at all. If a composite flower possesses them, they'll be found on the very outside of the flower structure. You can't miss the bracts found on artichokes; the bracts are the part you peel off and eat, usually with butter. Rows of bracts are called involucres.


The stem widens out just beneath the flower: the receptacle.

The receptacle of a composite flower is the top of the stem from which all the flowers arise. Though it isn't strictly part of the flower, it is a good starting place to identify the parts of a composite "flower," since parts occur in the same order on all flowers. Cutting a composite in half through the receptacle can help a gardener become familiar with the workings and structure of composite flower.


About the Author


Sophie Johnson is a freelance writer and editor of both print and film media. A freelancer for more than 20 years, Johnson has had the opportunity to cover topics ranging from construction to music to celebrity interviews.