The four whorls
The structure bearing the sexual parts of a plant is the flower.
The parts of a flower are arranged in whorls on the receptacle — circles of parts, one inside the next. There are four main floral parts.
| Whorl | Made of |
|---|---|
| Calyx | Sepals |
| Corolla | Petals |
| Androecium (stamens) | Anther and filament |
| Gynoecium | Stigma, style and ovary |
Figure to be added
Outside in, protection to reproduction
The order of the whorls is the order of their jobs. The outer two — calyx and corolla — protect and advertise. The inner two — androecium and gynoecium — reproduce. A flower that loses its petals can still set seed; one that loses its gynoecium cannot.
Activity 14.4
- Obtain a few flowers. With the help of a hand lens, observe and identify their floral parts.
- Turn a flower upside down and cut down through the exact middle of the flower stalk. Draw a labelled diagram of the longitudinal section of the flower.