(2449), and Slieve Bearnagh (2394). Westward, the hills are flatter, and less intersected by deep valleys. The mountains are drained by numerous streams, of which the following may be mentioned. The Shimna River flows eastward along the northern base of the range, and has on its lower course the woods of Tollymore Park, long noted as a botanical hunting-ground; southward, the Annalong and Kilkeel Rivers find their way through the two finest valleys in the district to the Irish Sea; while to the south-west, the White Water and Causeway Water, and further northward the Kilbroney, Ghann, and Moygannon Rivers descend into Carlingford Lough. The central northern slopes form the headwaters of the Bann, which flows through Hilltown on its long course of 97 miles to the northern ocean.

The lakes of the mountains are three in number, leaving out of account several ponds or marshes, which in winter alone assume any considerable size. Lough Shannagh is a sheet of water with an area of 36 acres, lying at an elevation of 1350 feet on a peculiar extensive shelf, which the officers of the Geological Survey consider an ancient sea-terrace. The Blue Lough is picturesquely situated in a deep hollow between Slieve Lamagan and Slieve Bingian, 1100 feet above sea-level; and the shallow Lough Bingian occupies a hollow on the adjoining mountain-side at an elevation of 1350 feet. On the northern lowlands, Altnadua Lough and Lough Island Reavy lie on our boundary-line; the latter has an area of over 250 acres, but on account of its now being used as a reservoir, and subject to fluctuations of 20 or 30 feet in level, it does not yield the store of aquatic species that might be expected in such an extensive sheet of water. Castlewellan Lake is, strictly speaking, outside our boundary, but was included in our exploration in order to try to confirm some old and unverified records.

The mountain-sides generally rise steeply, with deep valleys between, and occasional lofty cliff-ranges. These last, with the rocky banks of the streams, form the habitat of most of the rarer species. The lower grounds are well tilled, and usually offer little of botanical interest. The coast-line of the district is nearly 40 miles in extent the shores are low and often stony, but extensive sandy beaches occur east and west of Cranfield Point, and again from Newcastle northwards; only the southern extremity of the Newcastle sandhills, from which many plants have been recorded, come within our district. Low sea-cliffs lie south of Newcastle, and offer a suitable habitat for several species which fail to find a congenial home elsewhere. The gravelly point of Killowen, in Carlingford Lough, and the fields adjoining, yield a peculiar group of plants, all rare in

District 12, and not found elsewhere in the Mourne area :-Sinapis alba, Lepidium campestre, Thlaspi arvense, Malva rotundifolia, Carduus crispus, Linaria repens, Bromus sterilis. The limit of cultivation varies from 200 feet on the steep eastern sea-slopes to 800 to 900 feet in sheltered valleys, and may be averaged at 600 feet. The rainfall in the district is higher than in any other portion of county Down.

The geological and petrological features of the area under consideration are by no means complicated. Rocks of Lower Silurian age once covered the district, as they now prevail over almost the entire county. Through these ancient grits and slates, now much indurated and contorted, eruptive granite has been forced in such a volume as to form the great bulk of the mountains. Thus the present aspect of the range shows the old stratified rocks lapping round the flanks of the granite hills, which rise in a noble series of dome-shaped masses, culminating in Slieve Donard, at the north-eastern extremity of the range. Vast as these granite masses now appear, they were, without doubt, originally much greater. These hills may, says Professor Hull, "undoubtedly be considered as the roots of volcanic mountains, the trunks and branches of which have been removed by denuding agents." The denudation during the glacial epoch has been very great, as the thick and extensive beds of glacial débris, unproductive alike to the botanist and geologist, which occupy the lower grounds, amply testify. Near the centre of the range the granite is almost divided into two sections by a spur of the sedimentary rocks, which ascends to a height of 2198 feet on Slieve Muck North. Although the Silurian rocks, as they occur in the North of Ireland, generally yield but a poor variety of plants, still, on account of the numerous weathered crevices they contain, and the moisture which continually oozes out of and trickles over them, the grits in the Mourne Mountains yield a richer flora than the dry and massive granites. The flora of the range can only be said to be modified, petrologically, by the two classes of rocks just referred to. Sandstone is absent. An outlier of Carboniferous limestone is seen on the shore of Carlingford Lough, near Greencastle, but its area is too limited to have any effect on the flora. Trap, for phytological effect the near ally of limestone, occurs only as occasional dykes penetrating the older rocks. True Boulder Clay seems scarcely to occur in the district, but extensive beds of granite débris, the result of glaciation, are frequent, and banks of this drift, thrown across many of the mountain valleys, indicate the latest pauses of the retreating glaciers. The mountain-sides have usually a covering of peat, some

times of considerable depth, but peat bogs at low elevations, with their characteristic plants, are not met with.

Geologically, the Mourne Mountains form a distinctly defined area. The Slieve Croob range, which rises on the northward to a height of over 1700 feet, is cut off by some ten miles of Silurian rocks, a lowlying country diversified by rugged hummocky hillocks. The Slieve Croob granite, too, has been considered by the officers of the Geological Survey as having a different origin from that of the Mourne Mountains, and as being much more ancient. Therefore, neither geographically nor geologically does this mountain-group come within the limits of the Mourne district. The Carlingford Mountains, on the south, are cut off by a deep intervening inlet of the sea (Carlingford Lough), in itself a considerable barrier, but more especially are these mountains excluded by their petrological character. The basalts, hypersthenes, syenites, and porphyries of the Carlingford hills may represent the Mourne granites in time, but are very different in composition, and the replacement of slate by the pyroxenic group widely distinguishes these neighbouring ranges. The authors of the "Cybele Hibernica," therefore, were right in giving District 12 its present well-defined southwestern boundary, which is true botanically as well as geologically.

As might be expected, the fine mountain-group of the Mournes has attracted the attention of botanists from an early date. Dr. Sherard made some explorations in the range at the end of the 17th century; John White examined the flora of the district, and of the Kilkeel neighbourhood especially, and supplied notes of the local plants to the "Irish Flora" (1833). John Templeton, Dr. Mackay, and Dr. Stokes, and later Wm. Thompson, G. C. Hyndman, and Professor Dickie, botanized among the hills and valleys. In recent years T. H. Corry, C. Dickson, and H. C. Hart, and in cryptogamic botany Rev. C. H. Waddell and Rev. H. W. Lett, have each added their quota of information to our botanical knowledge of the district. Mr. Hart's notice of the flora of the Mournes' is the result of a very few days well spent among the mountains. To certain statements of his, such as the extermination of Cryptogamme crispa, the unfavourability of the mountain-sides for the growth of plants, &c., we venture to take exception, and the majority of his upper limits of species we have raised; taking an average on all the species of which Mr. Hart and ourselves record upper limits, our upper limit is over 100 feet higher

1“Plants of some of the Mountain Ranges of Ireland," Proc. Royal Irish Academy, Ser. 11., vol. iv., p. 238, 1884.

than his. Rev. H. W. Lett has given a voluminous Report on the Mosses, Hepatics, and Lichens (Proc. R.I.A., Ser. II., vol. i., p. 265, 1889) of the Mourne Mountains and a large surrounding area.

From the above remarks it will be seen that the flora of this district has already been fairly well, though not exhaustively nor systematically, worked out by the botanists who have preceded us. The present exploration was undertaken, not in the expectation of adding many novelties to our north-eastern records, but with the object of ascertaining fully the extent and limits of this mountain flora, not only in respect of rare species, but also the more common forms, and of settling definitely some old records which stood in need of either confirmation or confutation. The opportunities for this revision have been considerable. Our visits to the mountains ranged from May till September, and extended over the seasons 1889 and 1890. During this time we spent, separately or together, forty days in the district, and traversed on foot over 850 miles of mountain, valley, or road; scarce a cliff or a stream of the least importance but has been visited and revisited; and it may be claimed that our examination of the flora has been reasonably complete.

The annotated list which follows contains 584 species and 31 varieties; an appendix is added in which are given such species or varieties, 35 in number, as have been recorded from the district, but were not found by us. The total flora of the district may be taken at 593 species, made up as follows:-Indigenous species, 566; escapes, colonists, or casuals, 18; species recorded from the district, which, though not found by us, no doubt still exist in the neighbourhood, 9; total, 593. Leaving the excluded species out of sight, the 575 species composing the indigenous flora equals 70 per cent. of the flora of District 12, or 57 per cent. of the flora of Ireland—a fairly large proportion for an area so limited. The flora of the Mourne Mountains is, however, chiefly remarkable by way of negative characters:-the rarity of alpine plants; Ireland is not rich in alpines, but the Mournes, despite their loftiness, can claim only a fourth of the Irish species; the poverty in species of Watson's Atlantic type, there being present only a third of the Irish representatives of that group; and the complete absence of plants of the Germanic and Hibernian types.

Comparing the proportion of the total Irish flora, District 12 flora, and Mourne flora, with that of some of the principal orders in the same areas, we find that Caryophyllacea and Umbelliferæ, which are in excess of their due number in District 12, are also in excess in the Mourne district. Compositæ, Scrophulariacea, Amentifera, and

Filices, which have a proportionate representation in District 12, are over-represented in our district. Ranunculaceæ, Leguminosa, Labiatæ, and Orchidaces are under their proper ratio in District 12, and are similarly under the ratio in the Mournes. Rosacea and Cyperaceæ, though in excess of their due in District 12, are below the proportionate ratio in our district.

Out of a list of 88 species given in "Cybele Hibernica," as being the more remarkable plants of District 12 (Derry, Antrim, and Down), fifteen occur among the Mournes, being only 17 per cent. The fact that the essential feature of District 12 lies in its great basaltic plateau in the north-east, will no doubt account for this discrepancy.

The Mourne district is remarkably poor in poppies, as out of four species occurring in county Down, one only, our common P. dubium (aggregate), haunts the Mournes, and its colonies are few and far between. The Rubi of the district are not remarkable for variety, and mostly possess but small interest. One species, however, R. ammobius, a somewhat distinct form (si sic omnes !), only recently recognized as British, is new to the Irish flora. It is remarkable that of seven saxifrages found in District 12, one only, S. stellaris, inhabits the Mourne Mountains. To the Hieracia of the district we have paid particular attention, and during the period of our investigation gathered and dried some 250 specimens. We have to acknowledge with hearty thanks the kindness of Mr. F. J. Hanbury, F.L.S., who examined the greater part of this large series, and named them in accordance with the terminology of his splendid monograph of that critical genus, now in course of publication. The Hawkweed flora of the Mournes is exceptionally rich, no less than 14 forms occurring. Of these H. auratum has not previously been recorded from Ireland, and H. argenteum is new at least to District 12, the plant recorded under that name from the Mournes by Mr Hart being a widely different and most interesting form, which we hope will shortly be figured and described by Mr. Hanbury. In Amentiferæ the willows are fairly represented, and all the other genera grow in the mountain glens and on the cliffs. Among Coniferæ, Juniperus nana alone occurs. Trunks and roots of the Scotch fir are dug out of the bogs up to 1000 feet elevation, far above the limit at which it will now grow. The name of the town of Newry shows that in former times the Yew flourished on the borders of our district. The scarcity of orchids is remarkable, considering the extent of upland pasture apparently well

1 H. hibernicum, Hanb., Jour. Bot., Sept. 1892, p. 258 (added in Press).