GEOGRAPHICAL DISTRIBUTION OF FUNGI 175 



plants, which as a rule suffer more severely than unculti- 

 vated plants of the same kind. One reason for this is 

 that cultivated plants are usually introduced species and 

 far removed from normal conditions by the excessive 

 development of one special part, at the expense of the 



FIG. 48. Hexagonia apiaria, a dry, coriaceous fungus belonging to the 

 Polyporaceae, characteristic of tropical regions. Half nat. size. 



others. I have been much interested, during the examina- 

 tion of collections of plants from Arctic regions, to observe 

 the comparatively large number of parasitic fungi present, 

 mostly belonging to the Sphaeriaceae and Sphaeropsideae; 

 again indicating that under conditions presumably not 

 ideal for phanerogamic development the simpler fungal 

 element gained the ascendency. 



Cooke has given us the nearest approach to a general 

 distribution of fungi. 



