14 PEEAMBLE. 



the Edible Boletus is the type. One other 

 example, that of the Hedgehog Mushroom, 

 illustrates a type in which the gills, or 

 pores, are replaced by teeth, or spines, which 

 beget the whole of the under surface of the 

 pUeus, or cap. These three groups may be 

 distinguished from each other by features 

 which are distinct and unmistakable, so 

 that there need not to be a moment's 

 hesitation in their application. The few 

 additional forms which do not conform to 

 any of these groups need not be mentioned 

 here, but will be described hereafter under 

 their separate names. 



Keverting to the original definition, in 

 which a stem and pileus, or cap, are the 

 two elements, we must remark that, in the 

 gill-bearing fungi, this stem may have a 

 ring or collar surrounding it near the apex, 

 or the ring may be entirely absent. This 

 is an important feature in the discrimination 

 of species, since it forms a part of the 

 specific- character. It is present in the 

 Common Mushroom,-but it is absent in the 



