Featherwort, liverwort and the loss of moss

Another Life Michael Viney Mweelrea looms large in the window these mornings, holding back the sun until well past 9 a.m

Another Life Michael VineyMweelrea looms large in the window these mornings, holding back the sun until well past 9 a.m. Its northerly, shadowy face is seamed with rocky buttresses that spill out fans of scree on their way to the bog below. Once, in more limber days, I went up the hard way - well, hard for me: a long clamber up a chute of blocks and a final tiptoe across a shaky scree slope rather bigger and steeper than I'd bargained for.

One of the rewards was finding St Patrick's Cabbage in flower, a glossy-leaved saxifrage quite common among shady rocks of the western mountains (and just a bit different from "London Pride" that edged my childhood's garden path). It is on such high cliffs and scree slopes, keeping their eyebrows of hail and snow for weeks, that Ireland also holds on to the rarer Arctic alpine plants surviving since icier times, such as roseroot, alpine meadow rue, starry saxifrage, holly fern, cowberry. Praeger found them in drifts on these mountains a century ago. Some, I hope, are still hanging on wherever the sheep can't reach.

The story is different for the bryophytes, the mosses and miniature liverworts that once grew so richly in the shade of heather on high, north-facing slopes. Here, they formed a thick, wet carpet, brightly embroidered in pinks, purples and golds and known to botany, rather coolly, as "northern hepatic mat". Among the liverworts are several that have their European strongholds on the western mountains of Ireland and Scotland.

The most famous and intriguing, botanically speaking, is Lindenberg's featherwort, Adelanthus lindenbergianus, a liverwort of beautiful, rosy fronds (unlike the kind with leaves that overlap tightly, like tiles on a roof, to hold in precious water: even, perhaps, to trap minute insects as food). Apart from one patch on Islay in Scotland, and its last, isolated shreds in Mayo and Donegal, this plant jumps the globe to places like Mexico, East Africa and mountains in the southern hemisphere. In Ireland, it may well have waited out the Ice Age on a few rocky peaks sticking up above the glaciers.

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In 1962, a carpet of the featherwort and its distinctive companions was closely studied and described on the north slope of Bengower, in the Twelve Bens of Connemara, where the heather was then nine inches high. Recent visits to the same place by Scotland's David Long, a leading international bryologist and almost annual visitor to Ireland, found the heather cover quite vanished and no sign of the liverwort. As David Holyoak, conservation officer to the British Bryological Society, comments in the current British Wildlife: "It is already too late in Co Galway, without destocking, to allow the vegetation to recover, followed by reintroductions."

The news is not all woeful. In one day on Mweelrea this summer, David Long found a quite new Irish moss growing on a crag, another great rarity in the scree beneath and a third at a rocky stream downslope. Holyoak's own work in Mayo has added three mosses to the list, and Irish botanists have been making their own discoveries. They confirm that Ireland's moist, oceanic climate has given us a richness of bryophytes (seen most impressively, perhaps, in the spookier woods of Killarney) to compare with any in the world.

These may be "lower" plants, virtually unchanged since they crept out of the ocean 400 million years ago, but, as Long says: "Just because they're small doesn't mean they're not interesting. Once you get up close and really look at them, you realise they're incredibly intricate and beautiful." Indeed: their beauty quite defeats the dreary common names being conjured up for them: Dripwort, Wavy Flat-Moss and the rest.

Yes, but what are they for? A cheerless question, but there are answers. Bryophytes anchor scree on steep hillsides, hold bogs together, stabilise bare soil in fields and sand in dunes. They cushion the stab of raindrops, soak up water and delay the gathering of floods. They defend themselves with chemicals that stop bacteria attacking them and these, as Long believes, may be of use to medicine. In Ireland and Scotland in the first World War, vast quantities of sphagnum moss were collected for surgical dressings at the front because of their antiseptic and absorbent properties.

Mosses and liverworts thrive in winter: the nearest bog or conifer plantation, with high humidity and trickling drains, will offer great cushions of the commoner sorts. I once made a table-top garden in an old baking tin that gave me pleasure for months. If you must have the names, try the pictures in the new Collins Complete Irish Wildlife, or go after the lovely field-guide booklet for amateurs produced by Scotland's Carol Crawford (e-mail: tnrcmoss@aol.com).