dominants further south, and again Yellow Flag and Juncus are conspicuous in great clumps.

At Portachur a region of "rough pasture" has some meadow plants mixed with the usual marsh flora. Flag is dominant and Hemp Agrimony, Eupatorium cannabinum, Wild Angelica, Angelica sylvestris Linn., Caraway, Carum Carri, Sneezewort, Achillea Ptarmica Linn., Ladies' Bedstraw, Galium verum Linn., Meadow Pea, Lathyrus pratensis Linn., and Tufted Vetch, Vicia Cracca Linn., are abundant on the drier ground beside the marsh. A pool is covered with Lesser Duckweed, Lemna minor Linn., and contains masses of Smooth Equisetum, Equisetum limosum, rising above the water surface. Elodea is massed in the deeper water.

This survey of the marshes round the coast serves to indicate the changing character of the "rough pasture." Bogland becomes prominent where there is much water, poor in mineral matter, and where there is great accumulation of decayed vegetation. The steeper land behind the raised beaches furnishes more water, and it is noticeable that the west side of the island, the windward and rainy side, has more of the bog type of vegetation than the east side. Moreover, westerly storms in winter throw the waters of the high tides in over the coastal marshes on the west of the island.

The facies of the vegetation of the marshes is determined by the growth form of the numerous perennials that colonise these areas. Tall leaves and slender stems, sometimes unbranched, rise straight into the air, many in tufts, and impart to the coastal landscape a characteristic appearance. Everywhere the members of the Juncaceae, Cyperaceae and Gramineae appear in abundance, and the Yellow Flag with its long, flat, bilateral leaves, conspicuous all round the shores, reflects in its external form the peculiar conditions of the habitat. This is shared by many other plants, many of which are monocotyledons. It shows a certain harmony between the plant and the physical characteristics of its habitat. The numerous vertical leaves, in some cases cylindrical, give evidence of the limitation of transpiration, suggesting to the observer that there are physical conditions of the habitat that render this necessary. The physiognomy of the vegetation reflects, in a broad way, the assimilating conditions under which the plants live. Growing in a loose watery soil in which much mud and much decayed vegetable matter have accumulated, the plants found are mostly perennials growing from rhizomes that creep over the muddy substratum, forming, in places, a closely interwoven mat from which numerous adventitious roots go down into the loose soil. This soil gradually accumulates humous acids, and so, in time, the habitat becomes one that in relation to the physiological work of the plant is dry. Such a transition is strikingly in evidence round the shores where much bogland is found. Xerophytic adaptations are therefore not uncommon, due to one or more of many factorshumous acids, the toxic action of bacteria, coldness of soil, etc. The question which is of most importance it is difficult to determine, since experiments on the influence of any one factor can only reach tentative

FIG. 8.-Scrub of old cliffs, east side of Great Cumbrae, Hazel dominant. Note dense undergrowth.

conclusions, for isolation of factors is not the way of nature, where their interaction may bring about conditions whose effect on the plant is cumulative. Adaptation to physiological drought is specially in evidence. in the Ericaceae in which, in addition, Mycorhiza or partnership with helpful fungi is found, a symbiotic relationship existing also in the Orchidaceae. In Sweet Gale, common on the west shore, partnership with nitrifying bacteria in the root nodules solves the problem of obtaining nitrogen in a watery soil with little assimilable nitrogen. The incurled leaves of the heathers, enclosing pores (or stomata), an arrangement that checks the escape of vapour; the stem-like narrow vertical leaves of sedges and carices; the thick cuticle of Scirpus; the protected stomata of some plants: these are all adaptations devised to reduce transpiration in a habitat where absorption of an acid soil-water must be restricted. Moreover, internally, the presence of air-containing tissue or large intercellular spaces are adaptations to the bad aeration of the watery soil, poor in oxygen. There is, however, no general type of adaptation, the members of a family exhibiting different forms of adaptation, probably because they differ in their demands upon the habitat. Response is different because demand is different. Where cushions of Sphagnum moss occur, growing higher each year, insectivorous plants such as Sundew and Butterwort thrive in the moist soft carpet and are capable of raising themselves as the level of the moss rises higher. The leaves of the Bog-moss store water, each leaf consisting of a single layer of cells of two kinds, large empty water-storing cells with pores in the walls and small green assimilating cells. The old moss becomes peat, the humous acids preventing putrefaction. Such a substratum is poor in available nitrogen, hence the value to the associated plants of obtaining this element by the digestion of the non-chitinous parts of insects. These plants are frequently met with on the coastal marshes, being even more numerous here than on the moor at the top of the island. On the top of the Little Cumbrae Sphagnum with its associated insectivorous plants is abundant. There, it is to be expected. It is interesting to note that movement in geological times may bring about such "drainage" and other consequent conditions of habitat as to favour the development of bog or high-moor within reach of the sea, as on the raised beaches of the Great Cumbrae.

(b) Moor.-The highest part of the island, above the 300-feet contour, is a Calluna moor country with Erica cinerea and Scirpus spp., especially Scirpus caespitosus. The wet hollows are filled with Sphagnum (and Drosera), Erica Tetralir, and Cotton Grass. Two little lochs bear a rich fresh-water flora. In one of these Bur-reed, Sparganium ramosum, is present in masses, and Juncus supinus Moench., spreads over the surface of the shallow water. Potamogeton dominates the surface of the deeper water. On the margins are Marsh Trefoil, Rushes, Juncus communis and J. articulatus, and Bog Asphodel, while Marsh Penny wort forms a ground carpet on the soft mud. Sphagnum with Drosera is abundant on the west side. The other is shallower and is of the usual marsh type. Sphagnum,

Drosera, Polytrichum, Cotton Grass, Marsh Potentil, Marsh Pennywort, Marsh Galium, Bog Asphodel, Lousewort, Spotted Orchis, and Whorled Carum are associates, while the dominant plant is Juncus, especially Juncus articulatus. In the water Equisetum limosum grows.

(c) Woodland.-Approximately 170 acres are covered by mixed woodland. The Barbay Hill wood has dark areas of no undergrowth. Where light penetrates there are patches of Erica cinerea with Heath Galium, Tormentil and Blaeberry. This is the plant association adjacent to the wood on the west side, and it would seem to be invading the wood. At the north side of the wood the light areas are clothed by Bracken and Foxglove, Digitalis purpurea Linn. The Craigielea woods, which may also be taken as typical, contain Spruce, Picea excelsa Linn., Sycamore, Acer Pseudo-platanus Linn., Silver Birch, Betula alba Linn., Beech, Fagus sylvatica Linn., and Elm, Ulmus campestris Sm. Honeysuckle, Lonicera Periclymenum Linn., climbs high on old spruces now almost dead. The undergrowth is Foxglove, Red Campion, Lychnis diurna, and Wood Sorrel, Oralis Acetosella Linn., with occasional patches of Bracken, and of Male Fern, Aspidium Filir-mas Sw. (Fig. 7). The moss Mnium covers much of the moist areas. Where there is a thick carpet of the needle leaves and cones of firs there is no undergrowth, as the resinous nature of these does not permit of the life and disintegrating and decomposing work of fungi and bacteria in the formation of soil.

Fintray Bay plantation consists mostly of Scots Pine, Pinus sylvestris Linn., with occasional Hazel, Corylus Avellana Linn., and White Poplar, Populus alba, on the margins. The other small woods of the island are mixed deciduous and coniferous woods.

(d) Cultivated Land and Pasture.-In all about 760 acres of land are under cultivation with crops and grasses, oats and potatoes thriving well in the moist climate. There are some 370 acres of pasture. This type of land is found all over the island up to but not above the 300-feet contour. The intermediate and 100-feet raised beaches are usually of this type, a good example being the intermediate one behind Kames Bay (Fig. 6). There are 24 holdings on the island, covering on the average 69 acres. Much of the land formerly devoted to crops has become pasture-land. Cost of labour and of transport from the island has had much to do with this. The weeds of the cultivated land are those commonly found on the mainland.

(e) Scrub of Old Cliffs overlooking the Raised Beaches. Inland Braes (Figs. 8, 9, 10, 11, and 12). The dykes that pierce the Old Red Sandstone of the old sea cliffs are everywhere clothed with Elder, Sambucus nigra Linn., Ivy, Hedera Helix Linn., and Bracken, Wood-sage,. Teucrium Scorodonia, growing on the scree-covered ledges and at the base. Wall Pennywort, Cotyledon Umbilicus Linn., occupies crevices in the dykes, and is a xerophyte with rather thick leaves; its perennial and somewhat woody stock penetrates deep into the crevices of the rock. Scrub occupies the old sea cliffs now remote from the sea. The dominant trees from Lion Rock to Green Goat, on the east side of the island, are Hazel, Corylus