The centre of a flower of Helleborus orientalis, the Lenten Rose. The picture shows four concentric tissue layers of different types and function. The outermost layer comprises petals, here with purple markings. The next layer (open tubes, lime green) consists of nectaries, with a ring of anthers (pale cream, stalked) towards the centre of the flower. At the centre are four styles (red below, pale tips), bearing the terminal female stigmatic surface. These structures serve to ensure seed production. The petals are a visual attractant to insects; the nectaries offer insects a food reward. When the anthers mature, they produce pollen (not shown here) which adheres to the visiting insect, and so is carried to the stigmas of the next flower encountered, resulting in fertilisation. The Lenten rose is a popular hardy perennial garden plant flowering in late winter and early spring in the UK