English name: Donn’s grimmia
An acrocarpous moss that forms small, dark green to almost black cushions which do not readily fall apart when scraped off the rock. The leaves are straight when dry and held close to the stem, but spread slightly when moist. They taper into a fine hairpoint. Held upright on a straight seta, the capsules are olive-green with an orange-tinged lid when mature.
Capsules mature from spring to autumn.
In Scotland, Grimmia donniana has a scattered distribution as it is characteristic of hard, montane, acidic rock in exposed situations, especially where this rock is rich in heavy metals. BBS distribution map
Look out for Racomitrium lanuginosum nearby.
Confusion species: Grimmia pulvinata
scottishlichens.co.uk 