292 SAGACITY AND MORALITY OF PLANTS. 



eeolog-ists have now no doubt such a terrestrial con- 

 nection did exist during the Pliocene Period. 



To look over a list of British plants, drawn up in 

 botanical order, is to the botanist, acquainted with 

 the various origin of our flora, an occupation of great 

 interest. He there finds arranged in categorical 

 order species which came from centres geographically 

 wide apart, and whose habits are of the extremest 

 and most opposite character. Here for instance, is 

 the Alpine Butterwort {Pinguicida alpina) side by 

 side with the Pale Butterwort {Pinguicida liLsitanica) 

 above mentioned. It is certain that the former has 

 wandered down here from the Arctic regions, and 

 we are not less sure that the latter has crept up from 

 the Mediterranean area, or remained behind ever 

 since the early Pliocene Period. 



During the Pliocene Period, the dry land was 

 occupied, perhaps, by the same flora as we now find 

 scattered over France, Spain, and Portugal. The 

 North Sea separated England from what are now 

 Norway, Holland, and Belgium, and came down as 

 far as Kent. Beyond that the chalk extended in 

 an unbroken succession to France, for the Straits of 

 Dover were not formed until a much later period. 



As the temperature changed and became colder, 

 one by one these warmth -loving plants died out, 

 until eventually only a few were left in the southern 

 parts of the British Islands. We find them most 

 abundantly there, because the ice-sheet of the Glacial 



