Identification notes
The beginner bryologist in many areas will soon learn to recognize this familiar plant of tree trunks, branches, stonework and concrete, a feature of even the most unpromising and polluted city centres. If you know what an Orthotrichum looks like, this moss is a cinch, as no other British species has a white leaf tip. Its capsule, buried in the leaves, can attract a second glance on occasion, as the sixteen separated exostome teeth look very different from the more familiar peristome of Orthotrichum affine, which has the teeth fused in pairs – a quick glance at the leaf tips, however, and order is restored, often accompanied by a ‘Tut’ of derision. However, this contempt is unjustified, as familiarity with this neat little fellow is a pleasure denied those dwelling in many parts of central and northern Scotland, so respect is a more appropriate sentiment.
So, with what might we confuse it? We might suggest other species with hair points such as Schistidium crassipilum, Grimmia pulvinata and Tortula muralis as confusing common associates. S. crassipilum has a subtly different leaf shape with the leaf lamina more smoothly reaching the narrower-based hair point, the leaf margins in the upper half being almost straight. When capsules are present, the reddish exostome teeth of Schistidium are quite different from the straw-coloured ones of Orthotrichum. G. pulvinata has a capsule which is always exserted above the leaves and on a cygneous seta when young. In T. muralis, the hair-point is much longer than that in O. diaphanum and emerges from the leaf tip almost at right angles to the leaf margin. The capsule is exserted above the leaves here too.
Read the Field Guide account