Flowers in the Asteraceae (Sunflower Family) are really composed of many tiny flowers called florets.
There are two types of florets: ray florets and disk florets.
Disk florets make up the center of a flower head. Many tiny, vertical florets are tightly packed so that we see only the top of each disk floret.
Ray florets are arranged around the circumference of an Asteraceae flower. These ray florets look like petals.
Some Asteraceae have only ray florets and some have only disk florets.
The tiny flowers or florets are attached on a platform called a receptacle.
As the diagram at the right shows, composite flowers have miniaturized and simplified each flower, then packed a number of tiny flowers on their ends next to one another, on the receptacle.
The resulting cluster (composed of perhaps hundreds of florets) looks like just one flower.
The cut-away view to the right indicates that the disk florets in the
center of the composite flower head are both tiny and numerous.
Each ray floret appears as just a single petal-like flower.
Each composite flower can have hundreds of tiny disk florets in the central area.
Each tiny disk floret is a flower in itself.
Any of the four floral series (Calyx, Corolla, Androecium, Gynoecium) members may be present.
Disk florets generally have tubular corollas.
Composite flowers consisting only of disk florets ( no ray florets) are called discoid. Anderson's Thistle is a discoid flower
Ray florets are characterized by strap-shaped corolla or petal which is often 3-toothed
Sometimes the corolla is called a ligule.
The pappus is a tuft of hairs on the fruit.
Some composite flowers are composed entirely of Ray Florets. For example, the dandelion.
Examples of Asteraceae or Sunflower family at Echo Lake Camp