This cushion of moss, clinging to a wall top in the centre of Newcastle, is Grimmia pulvinata, also known as the grey-cushioned grimmia.
Many mosses are perplexingly similar in appearance but this one is instantly recognisable, thanks to the long hair-like extensions to the leaf tips and the spore capsules that have a coy tendency to rise upwards on their stalks and them plunge back downwards again into the cushion of leaves.
Grimmia is an amazingly tough little moss. Its hummocks, often perfectly hemispherical, freeze solid in winter and can survive prolonged periods of drought in those all-too-infrequent ‘cor-what-a-scorcher’ summers when rain fails to fall for weeks on end. They manage to survive drought thanks to droplets of dew that condense on those long hair points at night and are absorbed into the sponge-like cushion below.
If you're even only remotely interested in the miniature world of mosses, take a look at the British Bryological Society web site at http://rbg-web2.rbge.org.uk/bbs/bbs.htm
where you'll be able to identify most of the common species in your back garden by downloading their handy guide at http://rbg-web2.rbge.org.uk/bbs/Learning/malotag.htm
For the more ambitious bryologist, there's now a beautifully illustrated moss field guide on line at http://hosting.sleath.co.uk/bbs/ which will shortly be published in book form.
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I imagine this is the moss I find growing on large rocks in the garden. Certainly looks like it. Soft and spongy to the touch.
ReplyDeleteI had a look at the links, and downloaded the field guide. Fascinating subject Phil, and I never knew there were so many mosses in the country.
Hi Keith, It's a moss that's extremely common on rocks, roofs and walls everywhere and it seems to produce those capsules almost all year-round.
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