THE FUNGI 81 
acquired their specific peculiarities from this associa- 
tion. 
The structure of these parasites and saprophytes has 
become so profoundly altered in consequence of their 
peculiar mode of life that it is exceedingly difficult to 
decide as to their relationship with the green plants. 
Naturally all trace of carbon-assimilating organs has dis- 
appeared, and the cell-structure differs much from that 
of the Alge except in a small number of forms. The 
reproductive parts, too, as a rule are very different from 
those of the Alge, and it is difficult to see any structu- 
ral affinity between the majority of the Fungi and any 
green plants. 
There are, however, a number of fungi which show 
unmistakable resemblances to certain alge, and it is 
probable that these are really related to the latter. 
From this resemblance to alge they are commonly 
known as the Phycomycetes, or “ Alga-fungi,” and are 
opposed to the “ Mycomycetes,” or True Fungi, the latter 
showing no certain affinity with the Algz, although it 
is not impossible that they may be connected with them 
through the Phycomycetes. It must be said, however, 
that the whole question of the origin and affinities of 
the higher fungi is very far from being satisfactorily 
settled. 
THE PHYCOMYCETES 
This class embraces a considerable number of fungi, 
some of which show unmistakable resemblances to cer- 
tain alge, while the relationships of others to any green 
forms are by no means certain. Of the former class 
may be cited the water-moulds (Saprolegniacee) and 
G 
