FLORA. 28 



without being inconvenienced to the same extent as would Bretons or Provencals 

 under similar circumstances. On the other hand, foreigners born under brighter 

 skies generally complain about the paleness of the sun, and of the fogs, which in 

 some of the towns, where they are impregnated with the smoke rising from thou- 

 sands of chimneys, are very dense, and hinder the free circulation of the air. 



Flora. 



In its main features the British flora resembles that of Continental Europe, with 

 a strong intermingling of American species, increasing in number as we travel 

 towards the west. There are only a few plants not indigenous to Continental 

 Europe, of which the most remarkable is the jointed pipewort, or Eriocaulon 

 septangular e, a native of tropical America, found in the Isle of Skye and in the 

 west of Ireland, whither the gulf- stream has carried it. 



The researches of botanists have clearly estabhshed the fact that the existing 

 flora is the outcome of successive floral invasions which transpired during the 

 tertiary age, whilst the British Islands still formed a part of the neighbouring 

 continent. The first of these invasions of surviving species took place probably in 

 the eocene age, and is confined to the hilly parts of South-western Ireland. It is 

 an alpine flora, quite distinct from the flora of the Scotch and "Welsh mountains, 

 and has been traced to the Western Pja-enees. A second botanical province 

 embraces Devonshire and Cornwall, South Wales, and a considerable portion of 

 Southern Ireland. When this flora first obtained a footing upon the British Isles a 

 barrier must have stretched across what is now the English Channel to Brittany and 

 Normandy. Some of its most characteristic species are the beautiful ciliated heath, 

 the purple spurge, and the graceful Sibthorpia. A third invasion took place when 

 England was joined to the north of France. This flora is more especially deve- 

 loped in the chalk districts of South-eastern England. To this succeeded, during 

 the glacial period, an invasion of alpine plants, principally from Norway, which 

 survive on the hills of Wales, Northern England, and Scotland. When the 

 glaciers finally melted away, and the land emerged anew, there occurred the 

 fifth invasion, the last in order of time, but the most important in its influence on 

 the character of British vegetation. This invasion emanated from Germany, at 

 that period joined to the British Isles by a wide plain stretching across the southern 

 portion of the North Sea. This hardy flora rapidly spread over the country, 

 where it found a congenial soil ; it invaded Scotland and Ireland, mingled with 

 the floras of more ancient date, and pushed them back to the west and south-west. 



Though Europe has played the principal part in giving to the British Isles 

 their vegetable clothing, America, too, has contributed a share ; but whilst the 

 European species migrated by land, those of American origin were carried to these 

 shores, as to the coast of Norway, through the agency of the gulf-stream, and 

 hence they are most numerous on the Hebrides, the Orkneys, and the Shetland 

 Islands, where they outnumber European species. 



Climate has exercised a paramount influence upon the distribution of British 



