A clump of Syntrichia, which was sparsely fruiting, confused me until I pulled it apart and realised there were in fact three different Syntrichia taxa allgrowing together. The sample was collected from the very mossy roof of Pendine's Sunbeam Diner, whilst balancing on a fence to get access to the lower tiles; not forgetting to grab a few pics while I was there! S. ruralis var. ruraliformis was very obviously different and I assumed the rest, including the fruiting material, was going to be montana (which looked to be the dominant species). But, in fact the capsules belonged to shoots of ruralis var. ruralis, which is said to fruit infrequently. Under the microscope the leaves can't really be confused, but looking at the clump both macroscopically and with a hand lens the picture was puzzling, with a range of apparent intermediate shoots present. Single-species colonies are normally straight forward, but I've not encountered this three-way association previously - at least not knowingly!
Above: Fruiting shoots and leaves taken from fruiting shoots.
Below: Leaves taken from non-fruiting shoots of S. montana [NB. the field of view is the same size for all microscope shots]