Looking To See was wondering what in nature is blue.

That had me looking through my snapshots - a lot are untagged so it is never a completely pointless exercise, even if this thread strictly is. Turns out I have a lot of evidence of blue. I'll update this when I feel like it, and other members should also feel free to add their photos (but not stuff from the web, that would spoil it). Please correct any IDs as appropriate. 🙂

Right. Some of the commonest blue things in nature are flowers so here's for starters...

Exhibit #1:

Wood Forget Me Not (Myosotis sylvatica)