42 British Fungi, 



GEOGRArHTCAL DISTRIBUTION. 



According to the latest systematic work on fungi/ 

 tliere are over thirty thousand known species from all 

 parts of the world. This number^ of course, includes 

 what have been called form species, and yet in spite of 

 these vast numbers, owing to our imperfect knowledge 

 of the mycologic flora of many large areas, it is 

 impossible to compare the flora of one continent with 

 that of another, excepting Europe and North America, 

 yet sufficient is known to justify the statement that 

 fungi are as widely distributed as any other forms of 

 plant life. One great draw^back to the mode of life 

 adopted by fungi, that of beiog saprophytes or parasites, 

 as compared with chlorophyll-bearing plants, is their 

 dependence on the presence of the latter, because, 

 disregardiog the comparatively few fungi that depend 

 on members of the animal kingdom for their food, we 

 find that the great bulk of species obtain their food 

 directly from the vegetable kingdom, and to a very 

 great extent from the phanerogamic division. This 

 dependence is most pronounced in the case of fungus 

 parasites, and more especially in the numerous cases 

 where the fungus has become so specialized as to be 

 confined to the members of one particular natural 

 order of flowering plants for its host, and in many 

 instances even confined to a single species, hence the 

 distribution of parasitic fungi is limited to the dis- 

 tribution of their hosts. But as a rule the distribution 

 of the fungus is more restricted than that of its host ; 

 nevertheless, such minute fungi are often very per- 



2 Sylloge Fungorum. P. A. Saccardo. 



