Flowers are not colored for us, but for the insects or birds that pollinate them.
What appears plain to people are often multicolored in spectrums outside our own range of perception (i.e. viewed in the ultra-violet).
The coloured part of the Poinsettia, red,pink or white. is a bract or modified leaf. The flower is the small yellow parts in the centre. The Latin name is Euphorbia pulcherrima.
Because they are normally pollinated by moths or bats and have no need to be coloured - they normally have a strong scent to attract pollinators
The petals of a flower are brightly coloured to attract insects for pollination.
black
Flower petals are bright so insets can be attracted to them to collect the flowers nectar. Once the insects have collected the nectar some of the nectar fall and that's how more flower of the same kind grow. SO SOME TIMES YOU DON'T NEED FLOWER SEEDS TO GROW FLOWER'S.
hypothesis of double coloured flowers
The iris
use a white or some other coloured apricorn. im very sure itz white (rofl)
An Iris is a flower as well as part of the eye (it is the coloured ring around your pupil).
The petals of a flower are brightly coloured to attract insects for pollination.
mainly blue with some white
the pollen an the nectar