Mossy Invader

The invasive alien plant species that tend to hit the headlines are the large ones - like giant hogweed and Japanese knotweed - but there are smaller species that have snuck in largely unnoticed and have become an almost ubiquitous element in our flora. This is the Cape Thread Moss Orthodontium lineare which was unknown in Britain until 1922, when a bryologist called E.V. Watson found it on some rocks in Cheshire. Since then it has spread the length and breadth of the British Isles. It comes from the southern hemisphere, from Africa, South America, Australia and New Zealand, but until Watson found it the moss was unknown in Britain. Those drooping spore capsules are a distinctive characteristic and the fact that they are produced in such profusion in spring and release so many spores goes a long way to explaining how it has spread itself around so effectively.