This is a common plant of the base of damp shaded old masonry, especially where lime mortar has been used, such as churches, castles and other ancient monuments. Natural substrates include soft limestone and chalk, and it is particularly frequent in old chalk pits. It seems to prefer vertical surfaces. The leaves are up to 2mm long and at first glance it could be mistaken for Tortula muralis, with which it commonly grows, but that species has a strongly recurved border and usually a hyaline hair point. With a hand lens it is clear that it has a shorter yellowish/green excurrent nerve and a plane leaf margin. Most characterisic is the border of 2-3 rows of elongated cells which are more pellucid than the other lamina cells and give the border a shining appearance.
Any doubt is dispelled by examination under the microscope. Enthusiasts may wish to cut a leaf section to confirm a bistratose leaf margin, but this is not necessary for identification. Tortula subulata also has a border but this is a much larger plant with leaves over 3mm long and a mucro rather tan a longer excurrent nerve.Read the Field Guide account