Iris
Iris means rainbow in Greek. The name was given to the goddess of the rainbow, the flower, and the colored part of the eye.
The red leaves of a poinsettia are not part of the flower, which is small. They are differently colored normal leaves.
The petals of a flower are brightly coloured to attract insects for pollination.
Usually the petals are the colorfal/attractive part of a flower.
Zinnia.
It means that the plant does not reproduce by means of traditional flowers and seed is not formed within a closed ovary of the flower. Examples of non-flowering plants are: ferns and mosses which reproduce by means of spores, as well as gymnosperms which produce seed in "naked" ovaries (cones).
The male part is called the Stamen.
The part that receives the flower is the seedThe stamen receives the pollen then a seed pod in produced.
The iris
stamen
iris
it is called the pistil