This is a photo of the inside of a marsh gentian (Gentiana pneumonanthe):
Olympus XZ-1, 28mm, ISO400, f8, 1/40s
I initially made a photo where the centre bits were sharp as well, but that distracted too much from the petals and their colour and pattern, so I decided on reducing the depth of field and made this one. It looks better to me for sitting back and enjoying the colour.
Some bonus pictures, not for the challenge; this is a gentian from a more common perpective:
Olympus XZ-1, 28mm, ISO200, f6.3, 1/200s
These gentians are found near marshes and peat bogs, often accompanied by heather. There are usually several flowers per stem:
Olympus XZ-1, 28mm, ISO100, f5.6, 1/125s
I was also lucky enough to find this one in the local peatbog, the very rare white gentian, a variety of the same species:
Olympus XZ-1, 80mm, ISO100, f8, 1/400s
Marsh gentians have an associated species of butterfly, the alcon blue (Phengaris alcon); these butterflies only lay eggs on gentians. I'm still hunting for a photo of one of those, but while you wait, here's a related species, the silver-studded blue (Plebejus argus), that forages on the heather surrounding the gentians:
Olympus XZ-1, 112mm, ISO100, f5.6, 1/200s
Another rare species I found near gentians is this bog-rosemary (Andromeda polifolia):
Olympus XZ-1, 28mm, ISO400, f8, 1/80s
It belongs in the heather family (Ericaceae) and is only found in peat bogs.
The same goes for this rare marsh violet (Viola palustris):
Olympus XZ-1, 28mm, ISO100, f5.6, 1/100s
That's enough flowers for one day 8-). Edit: follow up: orchids.