Ultraviolet photograph of a Yellow Day-lily (Hemerocallis lilioasphodelus) flower. In the background behind the flower are a couple of flower buds that have yet to open.
The flower sports some very noticeable UV markings, with the throat of the flower appearing much darker than the rest of the petals. These markings, only visible in ultraviolet light, are often referred to as 'nectar guides'. Bees and some other insects can see ultraviolet light, and these markings help guide them straight to where the flower's nectar and pollen are located. In turn, this helps the flower get pollinated.
From Wikipedia (http://en.wikipedia.org/wiki/Hemerocallis_lilioasphodelus):
Hemerocallis lilioasphodelus, (syn. Hemerocallis flava, Lemon Day-lily Lemon Lily, Yellow Day-lily) is a plant of the genus Hemerocallis. It is found across China, in Europe in N.E. Italy and Slovenia and is one of the first daylilies used for breeding.
Hemerocallis lilioasphodelus grows in big spreading clumps and its leaves grow to 75 cm (30 in) long. It has lemon-yellow flowers with a sweet scent in a cluster of 3 to 9 flowers.
The flowers of some daylillies, including Hemerocallis lilioasphodelus are edible and are used in Chinese cuisine and Japanese cuisine.
Channel mixer used to modify colour in PS CS5
Hue adjustment in PS CS5
LCE applied in PS CS5