Marble Screw-moss - Syntrichia papillosa

Marble Screw-moss grows in small (2 to10 mm tall), dark green patches. The leaves spread when moist, and become incurved rather than twisted when dry. They are about 2.5 mm long, and broadly oval with an excurrent nerve. The margins are incurved and the nerve in the upper part of the leaf is covered with small, round gemmae, giving a very characteristic appearance. Capsules are unknown in Britain.

This distinctive species usually grows on mature trees; more rarely on walls, stones or tarmac. 

All year round.

It is infrequent throughout Britain and Ireland, but may be spreading. It is particularly associated with urban street trees and is often abundant on tree trunks in western towns.

Status in Leicestershire and Rutland not known.