Marsh Stitchwort

Couldn't resist putting in this photo taken from Rackham Wood looking west over Amberley Wild Brooks. It is thrilling to see a bit of 'old landscape' like this that was so nearly 'improved' like so many other grazing marshes. (Mind you, this too was 'improved' in the nineteenth century when ditches were cut to increase drainage.) In the northern section is some relic raised peat bog, the only example in the South East of England. Half of the UK aquatic flora are found here.

The species today is confined to such habitat. Marsh Stitchwort or Stellaria palustris is a member of the pink or carnation family. This family lends its name to the order Caryophyllales which includes the cacti, amaranths, ice plants, beets and many carnivorous species.
I initially thought it was greater stitchwort, which does look remarkably similar. The differences, however, are the smooth-edged leaves and the papery edges to the bracts which are just visible if you zoom in on the middle photo.