Identification notes
This is one of the commonest leafy liverworts to be found on rocks and other surfaces in watercourses and lakes where it usually grows at least partially submerged. You’re unlikely to find it in chalk or limestone streams or in other base-rich water as it prefers water with a pH of 6.5 or less. Scapania undulata is a common associate.
Typical-looking submerged plants are generally straightforward to identify. C. pallescens is more calcicolous than C. polyanthos so does grow on base-rich substrates. It typically favours damp terrestrial habitats too rather than the aquatic situations of C. polyanthos.
Ideally, plants with perianths should be sought to confirm identification of this very variable species but unfortunately for the field bryologist, they are often lacking. Habitat, leaf shape and the average number of oil bodies in the leaf cells (look at them fresh as they start to disappear on drying) can also be useful in their absence.
Read the Field Guide account
