British Isles, surrounded on all sides by the sea, are subject to much rain, and exempt from intensity of heat or cold; and thus, whilst they escape the severe winters experienced in similar latitudes on the Continent, they do not enjoy so much summer heat as continental countries. The consequence of this insular climate is, that some European plants requiring a high summer temperature, fail of coming to perfection in these islands; whilst other plants, which will not stand the severe frosts of the Continent, flourish with us. About three thousand three hundred species of plants are now known as natives of the British Isles, to which, however, a very small number are exclusively confined. And though some of these plants are here limited to small districts, it not unfrequently happens that they are met with in distant regions of the globe. Thus the jointed pipewort, (eriocaulon septangulare,) is confined to a few lakes in the Hebrides, and some spots in the south and west of Ireland, being found nowhere else in Europe; but also occurs in Canada; the trifid-leaved cinquefoil, (potentilla tridentata,) is only found on one hill in Angus-shire, which is its sole European station; but is abundant in Arctic America, and particularly on the Rocky and White mountains.

Some plants reach their northern limits in the south of England and Ireland. Among these, stands conspicuous the arbutus, or strawberry tree, which flourishes especially in the neighbourhood of the Lake of Killarney, where this beautiful tree attains a great size. The Cornish heath grows nowhere in Britain except Cornwall. The sweet violet scarcely reaches the middle of the kingdom; and Scotch bards, instead of celebrating the deep blue violet, sing of "the violet pale." The northern and Alpine districts, on the other hand, are not wanting in their peculiar indigenous species, whose range does not extend to the south of the island: such are the Scottish primrose, alpine gentian, &c. Some plants, again, are confined to the eastern, and others to the western districts of the island; the plants of the eastern coast having generally the character of those

which are natives of dryer and warmer climates. The flora of the country round London is, perhaps, not surpassed throughout the whole of England. Surrey is particularly rich in orchideous plants, which also occur plentifully in Kent. They are found, though less frequently, in Essex and Middlesex ; but are in great quantities in some parts of Hertfordshire. Kent and Surrey also contain many other rare plants.

Ireland, again, exhibits a few striking peculiarities in some of its vegetable productions. Besides the arbutus, already alluded to, it can boast the large-flowered butterwort, (pinguicula grandiflora,) a beautiful flower, also a native of France and the Pyrenees; the graceful menziesia, indigenous both in the latter locality, and in Spain, but found growing wild in no other part of the world; the London pride, or kidney-leaved saxifrage also, which is scarcely known to exist, except in this locality, and in Switzerland and the Pyrenees; the yellow poppy, a peculiarly arctic plant, unknown elsewhere in Europe, but plentiful on the northern extrémity of America, and in Greenland, &c. The Irish yew and Irish furze are considered to be peculiar to Ireland; and to these the Irish broom is added by some botanists.

The trees which appear to be aboriginal natives of Britain, are the oak, (two species,) the elm, (five species,) the beech, ash, maple, and sycamore, hornbeam, lime, (three species,) alder, birch, poplar, (four species,) aspen, mountain ash, yew, holly, and pine, or Scotch fir. To these may be added, though of less importance as timber trees, the willow, whitethorn, crab-apple, blackthorn, hazel, guelder-rose, bird-cherry, elder, &c.

In regard to the height above the level of the sea, at which some kinds of plants will thrive, it will be evident that the southern and midland parts of Great Britain do not contain mountains, or land of sufficient elevation, to afford any striking illustration of this natural distribution of plants; and if we find some of the elevated lands on the

southern coast devoid of trees, it may rather be attributed to their exposure to sea winds, and perhaps want of congenial soil, than to elevation above the sea level. In the north of England, however, the case is different: the mountains there rise to the height of three thousand feet, and an opportunity is afforded of observing the limits of various species.

The finest oaks are met with in the southern districts of Great Britain, especially in Sussex and Kent, the noble oaks of these counties being regarded as the best timber for the use of the navy*.

In the north of England, about lat. 55°, the oak still attains a large size in the valleys, but becomes of stunted growth on the hills, at the elevation of sixteen hundred feet; and in Scotland, except in some of the valleys in the south, it generally only forms copse woods. The common elm is not indigenous north of the Tees, its place being supplied by the wych elm, which skirts the mountains at the elevation of two thousand feet. The beech, which forms vast forests in the south of England, also flourishes in the low sheltered valleys in the north, but does not grow on the hills to the same elevation as the oak. The linden or limetree, one species of which appears to be indigenous to the counties bordering on Wales, and another to Lincolnshire, scarcely reaches the northern districts of England. Holly trees are among the chief ornaments of the woods of Northumberland, Cumberland, and Durham; in which counties the yew is also abundant. The birch attains a greater size in the north of England than in the southern counties, almost equalling in appearance the birches of Norway and Sweden. In Scotland it, however, becomes stunted at

* The annexed cut is from an original drawing of Sir Philip Sidney's oak, in Penshurst Park, Kent. In this view of the tree, a specimen occurs of the peculiarly formed diverging branches, to which the term nee-timber has been applied; at one period in great request in naval rchitecture.