Syntrichia papillosa
“marbled screw-moss”
How to recognize Syntrichia papillosa: This moss can be recognized by examination with a good handlens when the plants are wet since the oblong-obovate leaves with the very obvious awns have numerous round propagula or gemmae on the upper leaf. These propagula each can grow a new plant if they fall off in a good site. And the brick wall above must be a very good site. Under the compound microscope the quadrate cells each have a strong papilla on the back side of the leaf. The midrib also has many papillae on the back of the leaf. It is much less attractive when dry and the leaves are folded together and twisted and dark.
Where to find Syntrichia papillosa: This moss forms dense cushions and patches of plants usually on the bark of trees, but also on the mortar and brick of walls and it looks quite healthy on the brick wall in the pictures above.