Perianth

Biologists often use the term perianth to describe the calyx and corolla together. This is a useful term when the distinction between the sepals and petals is not clear. Sometimes the sepals are more obvious than the petals and can confuse even the most experienced observers. In this example of clematis, the sepals are large and showy while the petals are absent altogether.

Clematis
Clematis

Stamen