Anomalous Bristle-moss

“Anomalous” because it’s happy on masonry and stone rather than trees, like the other Orthotrichums.  And especially happy on my roof – although clumps often fall off.

It always seems to have plenty of hairy, ribbed capsules, whatever the time of year, starting off green and ending up reddish-brown.  They stick up above the leafy clump.

Apart from the clue provided by its habitat, the surest ID is apparently “the immersed stomata on the capsule wall” (Watson), which I’ll have to look for.