Moss puzzle

I did some work in Swansea Docks yesterday and finally managed to add 22 species to the previously unrecorded SS69Q. There was nothing of special note, though a single capsule of what superficially looked like Microbryum rectum seemed a little odd. The habitat comprised a mossy turf growing on a marine silt/grit crust over concrete, regularly inundated by wave spray during storms. The most prominent species were Limonium binervosum agg., Hennediella heimii, Didymodon tophaceus and Tortella flavovirens. Under the microscope the seta seemed thick and too long for M. rectum, plus the leaves looked more like those of H. heimii, with smooth cells, costa ending below the leaf tip and with a few marginal teeth near below the tip. I gently squashed the capsule under the slide cover to reveal some unripe spores. Given the habitat and the leaf characters I'm suspecting this is just a deformed capsule of H. heimii, but thought I'd post it, just in case someone else knows better.

Also of interest, the crusts of D. tophaceus were punctuated by frequent fruiting bodies of one of the bryoparasitic Pezizales, probably a Lamprospora species, though the Octospora website does not list D. tophaceus as a known host.