Anatomy of a flower

Angiosperms or flowering plants produce flowers soley for the reproduction of the plant. Like animals there are female and male reproductive organs.
Flowers are extremely diverse in size, shape, color, and many other factors. This means they are excellent for identifying plants and their relationship to other plants, especially as the flower does not change according to environmental conditions, unlike say shape of plant, leaves and stems.

The Female Reproductive Organs:
Includes an ovary (where ovules (contain an embryo sac with egg/s) develop into the seeds are produced after fertilisation), a style (a tube which supports the stigma on top of the ovary down which the pollen travels), and a stigma (a sticky bulb in the centre of the flower which receives the pollen during fertilization).

The Male Reproductive Organs:
The Stamen consists of an anther (sacs which contain pollen (which make sperm cells) that fertilise the ovules) and a filament (a long stalk which supports the anther). The filament lifts the anther up so that pollinators can gather the pollen, as well as a vascular supply to the rest of the plant.

Petals:

The petals attract pollinators with their shape and bright colours for many species. Also some flowers are fragrant to attract pollinators, while still others give off an unpleasant smell to attract different pollinators (eg blow flies). Also nectar is produced to reward and encourage the pollinator. Color patterns on the flowers , especially seen through the eyes of the pollinator, might include nectar guides to point the way, or a "bulls eye" target among the petals might get the flying pollinator to notice the flower and home in on it, or like a series of runway lights to guide in the pollinator.