CHAPTEE VI 



THE VEGETATION OF OALCAEEOUS SOILS 



Soils containing a comparatively large proportion of 



lime are always marked by the presence and 

 Calcicole and n i. j.i i, j x- j. • 



Caicifug-e usually by the abundance oi certain species 



species. of plants — the so-called " calcicole " species. 



That this feature is not determined by in- 

 ability of the species in question to flourish in the absence 

 of a large amount of calcium carbonate is sufficiently 

 shown by the fact that practically all of them occur and 

 flourish on soils poor in lime — if not in the same at least 

 in other regions. 



Contrasting with the "calcicole" species there are 

 others, called " calcifuge/' which appear to be really 

 intolerant of much lime in the soil. Examples of pro- 

 nounced calciEuge species usually quoted are the maritime 

 pine (Pinus Piiiaster), the sweet chestnut (Gastanea 

 sativa), and among native plants, the broom (^Sarothamnus 

 scoparius), and the foxglove (Digitalis purpurea). 



One explanation which has been given of the occurrence 



or abundance of calcicole species on cal- 

 Causes of the i • j.i j. t -i n 



distinction careous soils is that on such soils they are 



free from the competition of the calcifuge 



species, and are thus able to hold their own. The same 



explanation has been given of the occurrence of halophytes 



on salt-containing soils, and in that case with considerable 



