V. INEQUALITIES OF DISTRIBUTION. 441 



this species farther southward, and to the Highland 

 mountains where many of its Scandinavian alpine asso- 

 ciates find their congenial abode in Britain. 



At the other extremity of this island, Sibthorpia europaia 

 is found in some few of the south-western counties ; also. 

 Erica ciliaris still more locally there. On removal to 

 inland gardens in the south-eastern counties, these plants 

 will die away during dry summers, unless watered or 

 sheltered ; and they are occasionally killed by frost in 

 severe winters. Here, again, the inference seems clear 

 and warranted, that the damp and equal climate of the 

 south-western counties is a related condition of their 

 existence there ; the inference being further supported by 

 the fact of their occurrence under similar circumstances 

 elsewhere in western Europe. But this apparent adapta- 

 tion specially to the present climate of their localities, 

 gives no explanation as to the agencies which originally 

 placed them there. 



A first call on the phyto-geographer is to ascertain 

 where the plants are now distributed, and in what manner 

 and degree such present distribution accords with present 

 geographical conditions ; — how it appears related to lati- 

 tude and longitude, to elevation and climate, to soil and 

 situation, to continuities and disjunctions of the earth's 

 surface, &c., &c. The ingenious minds, that take their 

 delight in inventing causal hypotheses to account for 

 these present seeming relations, through reference to 

 supposed conditions of the past, will work more easily, 

 and perhaps with more truthful results, if supplied with 

 properly arranged data truly illustrating the present. 

 They may then possibly find out, instead of only feign, 

 phyto-geographical and phyto-geological histories. 



Hitherto, such data have seldom been better than 

 vague and partial ; never exact and complete. Any 



VOL. IV. 'i L 



