Cooke : Genera iind Species in Fungi. 413 



identical, although in different terms, and applied chiefly to 

 species. 



This theory was, that having regard to varieties and 

 ' abnormal ' species, their origin must be traced to hybridiza- 

 tion, and that most varieties, and many ' intermediary ' species 

 were hybrids. Of course the objection to this hypothesis was 

 then as it is now, that sexual characters have not been dis- 

 covered and defined in Hymenomycetal Fungi, and conse- 

 quently, as hybrids are the result of sexual association, there 

 could be no hybrids. 



Still the ultimate conclusion was the same, that one species 

 was linked to another naturally, and that the whole scheme 

 of existence in the Agaricinse was unity, and a graduated 

 sliding scale in which one species glided imperceptibly into 

 another through the intervention of varieties or abnormal 

 species. 



What also is the meaning of George Massee's application 

 of the theory of evolution in ' The Evolution of Plant Life ' 

 and ' Phycomycetes and Ustilaginese,' except that during past 

 ages, as well as the present, one form has been developed from 

 another, and that in plant life the parts glide imperceptibly 

 the one into the other, and constitute an unbroken chain of 

 organisms which we recognise as the ' vegetable world.' 



Thus, then, we observe that it is no new theory that one 

 form, or so-called species, merges into another by links, which 

 are now sometimes obscure or missing, but which unite, not 

 only all the members of one natural order with another, but 

 also the larger groups such as the Fungi with the xA.lgae, and other 

 of the Cryptogamia, although we may have to travel back 

 thousands of years to realize their association. 



This, then, is a slight and imperfect sketch of what we mean 

 when we say that there are, in nature, no such hard and fast 

 lines of demarcation as those artificial groups which we call 

 orders, genera and species. 



It may be hard to believe this all at once, but it is a hypo- 

 thesis which age and experience will strengthen, and should not 

 be discarded, because so many of the links have died out, or 

 are otherwise missing. 



Finally, we are reminded how many species (so called) have 

 been figured, or described, by old authors, of which no repre 

 sentatives have been seen in these latter days, and which were 

 ])robably good and genuine figures and descriptions, but are 



igog Dec. i. 



