already very dramatic landscape. The Benbulbin area, extending from Co. Sligo to Co. Leitrim, is so extensive that it would take a botanist at least seven days, working at a feverish pitch, to do the place justice. There are, however, two ‘hot spots’ for the arctic-alpines and alpines.
The first area is the cliffs of Annacoona in the Gleniff Valley, guarded at the northwest entrance by Benwiskin (514 m) which rises to a remarkable pinnacle, like the Matterhorn, surveying the landscape. The Annacoona cliffs face northeast, overlooking the great cirque of Gleniff, gouged out by a glacier. On a still summer’s day the croaking of ravens, rolling around and playing aerobatics along the steep cliffs, the occasional shrieking of a peregrine and the bleating of sheep are the only sounds in this otherwise silent valley. On the cliffs at Annacoona the arctic-alpine flora starts from an altitude of about 244 m upwards. The rarest species is fringed sandwort which has its home here on the upper sections of the limestone cliffs, between 300 and 550 m. This small and deceptively dainty, white-flowered and slightly hairy perennial is a member of the Caryophyllaceae or chickweed family and was first discovered by the eminent Welsh antiquarian and natural historian Edward Lhwyd on one of his visits to Ireland in 1699. He recounted the discovery in a letter to Tancred Robinson, a great friend of the British botanist John Ray: ‘In the same neighbourhood on the mountains of Ben Bulben and Ben Buishgen, we met with a number of the rare mountain plants of England and Wales, and three or four not yet discover’d in Britain.’28 Irish specimens of fringed sandwort were assigned to the special endemic subspecies Arenaria ciliata subsp. hibernica by Ostenfeld & Dahl in 1917 who also separated off two other subspecies, A. c. pseudofrigida found in arctic Europe and Arctic sandwort A. c. norvegica found in Shetland, arctic Europe and America.29 There is one record of A. c. norvegica from the Burren in Co. Clare but it has never been rediscovered despite repeated attempts by many botanists. Endemic species, or subspecies, are restricted to a specific geographic region and have evolved the differences that separate them from their close relations due to their isolation, or in response to soil or climatic conditions.
Annacoona is the only known Irish station for alpine saxifrage, first discovered here by the botanist John Wynne in 1837. Its leaves are purple underneath and it has a very hairy inflorescence with white petals and reddish sepals. Within the Benbulbin area alpine meadow-rue is also confined to Annacoona. Amongst the species listed by Praeger found on the cliffs and escarpments, the following occur in profusion:3 alpine scurvygrass, hoary whitlowgrass, mountain avens, yellow saxifrage, mossy saxifrage, brittle bladder-fern, green spleenwort, limestone bedstraw and common milkwort. More locally abundant are lesser meadow-rue, moss campion, purple saxifrage, upland enchanter’s-nightshade, mountain sorrel, tea-leaved willow, blue moor-grass, holly fern, beech fern and Irish eyebright. Raven in Mountain Flowers writes that the Benbulbin eyebrights he saw on his visit resembled some, but not all, of the specimens of Euphrasia lapponica he had seen in isolated populations in northern Scandinavia1. The following species are rare: Welsh poppy, wood vetch, several hawkweeds including Hieracium hypochoeroides, cowberry, alpine bistort, dwarf willow, juniper, stiff sedge, maidenhair fern, large thyme and alpine meadow-grass (found only here and on the Brandon Mountain, Co. Kerry). Isolated trees or small clumps of them, firmly rooted in the vertical cliffs, are a curious sight – rock whitebeam, wych elm and yew are all present, only ever to be touched by birds and flying insects.
The other interesting place for arctic-alpines and alpines is a section of the north-facing cliffs some 5 km northeast on the Tievebaun Mountain, Co. Leitrim. The cliffs are northwest of Glenade Lough. The exciting section extends for about 800 m at an altitude of 213–366 m. Many species already growing at Annacoona are found here, together with the chickweed willowherb, a unique speciality of these precincts. First discovered here by R.M. Barrington and R.P. Vowell in 1884, it is a low, small, creeping, almost hairless willowherb with runners above the ground. The flowers are purplish-pink and the seed pods turn red when ripe. Partial to streams and wet places, especially dripping rocks, this willowherb has two sites at Glenade. The first is a wet cliff, where 100 plants grow in an area of about 25 m2. The second occurs along a small stream where a 30 m stretch accommodates about 70 plants. Also at Glenade, on an inaccessible vertical cliff, is the northern rock-cress, at one of only two locations in Ireland, the other being a site in the Galty Mountains, Co. Tipperary.16 This rock-cress is a small, slightly hairy plant with lobed lower leaves and small white, sometimes lilac flowers born on flowering stems some 8–25 cm tall. The seeds are carried in a long flattened pod. Golden saxifrage is here, found in wet spots on the cliff between 215 and 366 m. It is low and loosely tufted perennial with spreading and creeping stems that are square. The flowers are small, yellowish and without petals. Wych elm and rock white-beam grow on the cliff face wherever they can get a toehold.
One curious feature of Benbulbin’s flat top, as previously mentioned, is its covering by a thick blanket of peat bog, with all the attendant peatland plants. Where the underlying limestone pokes up through the vegetable skin a calcicole flora develops including several alpine species. During the colonisation process several species of mosses, especially Breutelia chrysocoma, settle on the limestone pavement, thrive and proliferate, and they soon produce layers of humus which can then be colonised by the seeds of heather and other ericaceous species. The new arrivals draw most of their nutrients from the acidic moss humus rather than from the limestone below by ensuring that their roots grow initially upwards or horizontally.30 Gradually the bog builds up, becoming more and more acidic with time, and the plants then exist on whatever nutrients they can draw from their own mounting pile of peat humus plus those that fall out of the sky with the rain.
Slieve League, Co. Donegal
‘One of the finest things of its kind’ was how Praeger described the mountain of Slieve League which brutally confronts the Atlantic Ocean at the end of the southwestern promontory of Co. Donegal. Made up of very old rocks – ancient schists, gneisses and quartzites laid down some 500 million years ago and then thrust up in the Caledonian upheavals – Slieve League rises to 595 m at its summit. It is essentially a quartzite peak, with some Carboniferous sandstone and even less limestone occurring on the summit. Like the Benbulbin mountain range it was almost certainly ice-free in days of glacier supremacy, a haven for arctic-alpine plants and other refugees. The southern side of the mountain has been truncated by the continual pounding of the Atlantic to form some of the most impressive cliffs in Europe. At sunset, the cliff structures, made mainly of quartzite and gneiss, glint and reflect the light in a way that signals their long and tortured history. On the north side of the mountain more cliffs plummet from about 460 m, equally dramatically, down to the dark and seemingly sinister Lough Agh that sits at an altitude of 245 m. Starting from the village of Teelin to the southeast, one of the best walks in Ireland can be had by ascending the summit including a bracing passage along a knife-edge ridge, appropriately named ‘One Man’s Path’. The northern precipice is one of the finest sites in Ireland for arctic-alpine plants and has attracted the attention of many distinguished botanists and naturalists for more than a hundred years. The number of arctic-alpine species is greatest here, and progressively declines southwards down the west coast and even more rapidly as one moves southwards along the east coast of Ireland.
Not only is the total number of arctic-alpine and alpine species on the north-facing cliffs of Slieve League the largest in the country but there are more species here than in any other similar habitat of comparable size in Ireland. Hart, who lived in Donegal and was at leisure to climb up and down Slieve League, reported many in his Flora of the County Donegal,31 thus supplementing earlier work.32 The species, listed again later by Praeger in The Botanist in Ireland include bearberry, green spleenwort, stiff sedge, mountain avens, dwarf juniper, alpine clubmoss, mountain sorrel, alpine bistort, holly fern, dwarf willow, alpine saw-wort, yellow saxifrage, purple saxifrage, starry saxifrage, roseroot, lesser clubmoss and alpine meadow-rue.
Slieve League cliffs, Co. Donegal.
H.
