EDIBLE MUSHROOMS. 79 



TRUFFLE. 



Tuber cvstivum. 



(Plate IX. Fig. 4.) 



This enumeration would not be complete 

 without mention of the Truffle, which is 

 found buried in the ground like a potato, 

 but without any indication on the surface, 

 so that it is not easily to be found. It 

 favours chalky or limestone soils, such as 

 the Sussex Downs, and formerly was hunted 

 by truffle-dogs, trained for the purpose. In 

 these days most supplies come from France, 

 as they are imported at a cheaper rate than 

 our native species could be collected, so that 

 the industry with us is nearly extinct. The 

 French truffle is not precisely the same 

 species as our own, whilst some consider it 

 preferable. It is nearly black, with a rough, 

 or obtusely warted surface, and mostly 

 irregular in shape, from the size of a walnut 

 to that of an apple, with a strong pene- 

 trating odour. It is employed chiefly for 



