Close-up ultraviolet photo of flowers of a Lobelia cultivar. In UV the flowers appear quite dark, areas of damage on the petals shows up as brighter patches.
The flowers are a deep red colour (in visible light) with five lobes. The bottom three lobes are fanned out, while the top two lobes are erect. (The flower on the right in this image is missing its top left lobe).
Colours modified in PS CS5