464 X. GENERAL REMARKS. 



bear also upon Vestigian views, when these shall have 

 been corrected and made scientific by help of Darwinian 

 discernment. 



Such an increasing departure from floral identity might 

 reasonably be expected, in passing from polar coasts to 

 intertropical mountains, on account of the increasing dis- 

 similarity between the climates of high latitudes and of 

 high altitudes. The slighter variations of temperature in 

 low latitudes being found also on their mountains (al- 

 though the mountain climate may not be quite so uniform 

 as that of the plains and coast-line beneath them), the 

 arctic-alpine flora of high latitudes gradually gives place 

 in low latitudes to one less adapted to bear extreme cold ; 

 while various species of this latter temperate-alpine or 

 tropical-alpine flora still require no higher temperature 

 for their season of growth, than is required by the arctic- 

 alpines ; perhaps even demanding a relatively lower tem- 

 perature. Partly on this account, it may be, that we see 

 the mountain plants of more southern latitudes growing 

 well in our un-heated garden frames during mild English 

 winters, and some of them even freely flowering, if barely 

 preserved from frost by night ; although the day tempe- 

 rature remains too low in such frames, to allow the simul- 

 taneous development of the alpine plants of Scotland and 

 other more northern lands ; which consequently continue 

 dormant there until the sunny warmth of spring raises 

 the temperature for them by day. Calceolarias grow, 

 and flower, and even seed, in a temperature which leaves 

 Saxifrages torj)id ; and jet the slight frosts of spring and 

 autumn, which growing Saxifrages bear with impunity, 

 are fatal to those same Calceolarias. 



But our immediate concern is with this island and its 

 own plants. The upper mountain flora of Britain still 



