716 ACCLIMATISING OF PLANTS. 



1. The sub-region of Fucus canaliculatus. 2. The sub-region of Lichina. 

 3. The sub-region of Fucus vesiculosus, F. nodosus, and Oorallina oflSci- 

 nalis. 4. The sub-region of Fucus serratus. The littoral zone is 

 succeeded by narrow belts of such Seaweeds as Himanthalia lorea, 

 Conferva rupestris, Laurencia pinnatifida, Chondrus crispus, and C. 

 mammillosus. The second or Laminarian zone commences at low- 

 water mark, and ejftends to a depth of from 7 to 15 fathoms. Here 

 we meet with the great Tangle Seaweeds and deep water Fuci. 

 Species of Laminaria, Ehodymenia, and Delesseria, are found in an 

 upper sub-region of this zone. In the lower sub-region they are rare, 

 and are succeeded by the coral-like Nullipore. The zones below them 

 are entitled the Coralline zone, extending from 15 to 50 fathoms, and 

 the region of the deep sea corals from 50 to beyond 100 fathoms. 

 These zones do not exhibit any conspicuous vegetable forms ; they are 

 characterised by the presence of certain animals. 



Acclimatising of Plants. — It is commonly supposed that by 

 length pf time plants may be rendered fit to endure a climate which 

 they could not stand in the first instance. It has been said that by 

 slow degrees tender plants may become acclimatised to cold climates. 

 Such a view, however, is totally inconsistent with the facts of the 

 case. Each species of plant naturally bears a certain range of tem- 

 perature, and it is impossible to extend that range. Many plants 

 originally placed in greenhouses, and subsequently planted out, are 

 held up as cases of acclimatisation. Aucuba japonica, coming from a 

 warm climate, was at first treated in this country as a stove-plant, 

 and was afterwards planted out, and was found to endure the climate, 

 but no change was made in the constitution of the plant. It was 

 capable from the first of enduring the cold of this climate. Apono- 

 geton distachyum, an aquatic from the Cape, was cultivated long in 

 the stoves of the Edinburgh Botanic Garden. A specimen was acci- 

 dentally thrown into the open pond, where it has continued to live 

 and flower for many years. The constitution of the plant is unaltered. 

 It was able to bear a certain range of temperature, but cultivators 

 were not aware of this in the first instance. Its roots are deep in the 

 mud of the pond, which is supplied by springs. Plants sent from 

 warm countries, and supposed to be delicate, are often quite hardy, 

 inasmuch as their native locality has been high on the mountains. 

 Such is the case with Araucaria imbricata from Chili, and with some 

 Nepaul and Japan plants. Again, take the Potato, the Dahlia, Helio- 

 trope, and Marvel of Peru, which have been long cultivated in Britain, 

 and it will be seen that they are not in the slightest degree more 

 hardy than when first introduced ; they are injured by the frost just 

 as easily as at first. 



It is of importance to define accurately what is meant by saying 

 that a plant suits a particular climate. It is not enough that it lives 



