Identification notes
A rather rare and eye-catchingly hoary-leaved species, and one of a select band of 4 calcicoles in the 29 British and Irish species of Grimmia. It does not have capsules.
Its habitat will provide the biggest clue to its identity – it is mostly confined to soft Jurassic oolitic limestone (Bath Stone) in the Cotswolds, a habitat unlikely to appeal to any other Grommia species except the ubiquitous G. pulvinata and, more rarely, G. dissimulata, which is much less hoary-looking and strongly resembles G. trichophylla.
G. tergestina looks most similar to G. laevigata, but that species is a calcifuge and will not be found on basic substrates.