Mature bryologists who remember the 1970s will know that there was a time when finding this moss on an old tree in a nice woodland would have been a great cause for celebration. More recently, it has become much commoner, possibly due to reduced SO2 levels. Further, it seems to like relatively nitrogen-rich situations such as the bark of urban trees, elders near intensively managed farmland, tarmac, and that may also have helped to fuel its spread in recent years.
Its typical habitat is still mature trees, but it occasionally ventures onto stonework too, though much less often. When moist, it is an easy species to recognize, as its pointed leaves, with inrolled leaf margins almost hiding a crop of small green gemmae on the upper leaf surface, are very distinctive. Picking it out when dry is trickier. Each individual plant then forms a group of spikey, grey-green leaves, looking almost prickly, the leaves pressing together at the tips with the excurrent nerves poking out. A quick squirt with the squeezy bottle will confirm the identification, as the plants rapidly rehydrate to reveal the little gemmae.Read the Field Guide account