Growing in damp, steep grass on bankside near to, but not in a sphagnum marshy area. Skye, Scotland.
No interactions present.
Shame you can't quite see inside the flowers to get one of the key distinguishing features.
I'm sure Mike won't mind me expanding on his ID point. The key difference between P. bifolia and P. chlorantha is the position of the pollinia - the mass of pollen grains inside the flower. In P. bifolia they are more or less parallel and close together. In P. chlorantha the bases of the polinia are well-separated. This really is almost the only way to tell them apart. I have seen quite small, rather dainty specimens which I thought were probably P. bifolia until I examined the flowers and found that I was wrong and vice versa. They are in fact extremely close genetically. So without a really close-up shot of the inside of the flower I don't think it is possible to tell whcih one this is.
BSBI VC Recorder
Lat/Lng: 57.4, -6.7
OS grid ref: NG1853