There are a couple more photos here but that's it. http://www.flickr.com/photos/highlandfairy/3379442568/ Thank you
Thanks, yes, the close-up helps, it looks like a Dianthus, perhaps Dianthus barbatus. If not Dianthus, then some other related plant in the family Caryophyllaceae.
I don't know either! Was it very far from any habitation? If it was far, then more likely some other related species. If not too far, particularly perhaps upstream, it could be from seeds washed down from a garden.