I think this is it in the perigonial region of Polytrichum commune.
Growing along base of Calypogeia and Riccardia along fen bank. Remarkably blue.
edge of arable field, on a piece of muddy, clay ground
Cushions on limestone rock in grassland. Some had capsules. Setae 2cm tall. Leaves enfold base of seta.
Cushions on limestone scree. Leaves 2-4mm long. Lots of short-leaved shoots.