If you find much of this moss, it will indicate that you are in an area where there is good air quality, and where airborne levels of sulphur dioxide are low. Since being eliminated from many industrial areas in the 20th Century, Cryphaea heteromalla has steadily been recolonising, although it is still scarce in places.
Like some ferns, C. heteromalla is unusual in having shoot dimorphism (heteromallous means pointing in different directions). If fertile shoots are present, they always stick up from the creeping, sterile shoots. In this way, the spores catch the wind and are effectively dispersed. Fertile shoots bear capsules on crowded, one-sided dwarf branches which give them a very distinctive bottle-brush appearance in the field, especially when seen silhouetted on a branch. It is a strict epiphyte, preferring base-rich bark of ash, field maple, willows, elder and other species, especially where the light is good, such as at the edge of a woodland, in hedgerows and on solitary trees.
Fruiting plants can only be confused with Dendrocryphaea lamyana, a rare and much more robust species of tree roots, trunks and rocks by a few large rivers in SW England and SW Wales. However, sterile plants are rather anonymous-looking and could be mistaken in the field for several other bark-growing pleurocarps such as Leskea polycarpa and Habrodon perpusillus, a rare epiphyte that appears to be increasing in some areas.Read the Field Guide account