28 CONIFEROUS PLANTS. 



severely nor so frequently from spring frosts as those 

 occupying warm and sheltered situations. 



But apart from the general principles which obser- 

 vation is enabled to gather of the relation of climate 

 to vegetation, there are in every locality peculiarities 

 in the seasons, a knowledge of which can only be 

 gleaned and properly applied upon the spot where 

 they occur. General principles are only valuable as 

 such ; practice and observation can alone render them 

 of real value. 



Soil. Naturally Pines do not affect deep or rich 

 soils: dry mountainous districts are their favourite 

 habitats. Some few species are, however, found to 

 prefer deep and fertile soils, amongst which several 

 of the Abies are conspicuous. In cultivation, a 

 general uniformity of soil is found to be productive 

 of satisfactory results ; but in planting large districts, 

 presenting a diversity of soil and situation, a selection 

 of the most suitable species for each will not only be 

 desirable but necessary. For although all, or nearly 

 all, the species will succeed well in a similarity of soil 

 and situation of a favourable character, such, for 

 instance, as would be afforded them in a collection 

 of the different species constituting a Pinetum, there 

 are only certain kinds that could be advantageously 

 employed under adverse circumstances, as on barren 

 hills, or marshy districts, or on the sea coast. Clas- 

 sified lists of the most suitable kinds for different 

 districts will be found in another place : at present we 

 confine our remarks to the Pinetum. 



The situation chosen should, if possible, present a 



