Walking in the woods last week I could not fail to notice something that rivalled even the gold and orange of the falling leaves for vibrancy of colour. Everywhere I looked – on tree trunks, stumps, rocks, even the bare soil – was brilliant green moss! Or perhaps I should say mosses, for as you look more closely you quickly discover difference of structure and of colour, indicating that several species of moss are decorating this habitat and now, as everything else dies back, they come into their own.
Mosses are divided into two main groups according to whether they stand upright or trail; after that, identification is trickier. However, I was very happy poking about, recognising and appreciating some of the main features. Everywhere there were emerald cushions of individual upright stems; then I discovered others – branching and re-branching like miniature ferns and the most beautiful lime green. One of my favourites is very common – a darker green and with the leaves growing around the stem to form a star shape at the tip – very pretty, particularly viewed through a lens or magnifying glass. So far so good, but to understand more I needed expert help so, as I always do in such circumstances, I consulted our WNS experts, and it seems that mosses are as fascinating as they are beautiful.
Together with liverworts (their closest relatives) and also ferns, mosses predate the evolution of flowering plants. Their method of reproduction is complicated: it does involve a sexual phase where male and female material combines but it’s the next phase we are likely to notice. The moss produces thin stems on top of which are little, usually brown, capsules full of spores. In suitably dry airy conditions the tops of these dry out and shrink back releasing the spores to be carried away to form a thread-like mass from which the new plants grow.
Another familiar to all walkers is sphagnum, found in the boggy areas on our peat moors. Looked at closely it’s lovely – all shades of pink, ruby-red and even orange mingle with tender green. All mosses can absorb moisture but sphagnum is the star: it can absorb twenty times its weight. This, together with its acidic nature – repulsive to bacteria – made it much sought after for dressing wounds in World War 1. Laplanders pack their boots with dry sphagnum for insulation; in Scandinavia it is used as nappy padding – absorbent and biodegradable! It is even used to sop up oil-spills and the resultant mush when dried out and compressed is available as fuel. Our sphagnum bogs are hugely important to us in Wharfedale. They act like giant sponges holding rainwater and releasing it in a gentle trickle into our network of ditches, streams and, finally, the river – protecting us from flash flooding. How’s that for brilliant green?