The first pointer to this beautiful epiphytic moss is its very small size, which will catch the eye in comparison with the more familiar Lewinskya affinis. Next, the long, hairless, greenish calyptra, covering pretty much the whole of the long, narrow capsule. Now, a finer point: The leaf margins are recurved, except at the tip, giving many of the leaves a channelled appearance with a peg-like tip poking out at the end. Finally, steel yourself for this one, as a steady nerve and a good quality hand lens are needed: the stomata in this species are confined to the lower part of the capsule (the ‘neck’). After you have pulled off the calyptra from an unripe capsule, you can actually see these as small, pale green dots. Believe me, it’s true! On L. affinis the stomata spread much further up the capsule length.
Much rarer, small epiphytic species such as O. pallens, pumilum and schimperi can seem superficially similar, but their capsules are much squatter, broader in comparison with their length than those of O. tenellum. If in any doubt, do take suspicious looking Orthotrichaceae back for microscopical examination, as the rarer species are easily overlooked. There’s no shame in returning home with a few packets for checking.Read the Field Guide account