I've seen a lovely little alpine (I think) flower in someone's garden and I'd love to know what it is so I can get some! It looks a bit like a daisy in form, but bigger, it has long, slim petals around a dark centre, the flower is about 2" across and opens wide out in sunshine but seems to close again in the shade. The flower is a dark bluey/purple colour, a bit like the colour of a dark Michaelmas daisy, the stem is short, and there is a small amount of slightly feathered foliage. Anyone know what this is?