162 PLANT LIFE 
fruit. We often speak of them as degraded 
or degenerate forms, but this is a somewhat 
loose and inaccurate form of expression. The 
vegetative structure has, it is true, been 
simplified, but in such a way as to render 
the plants much better adapted to the new 
conditions of nutrition than they ever could 
have been had they retained the complexity 
appropriate to the green ancestral type. 
For the moment we will pass over the 
bacteria, which differ in many respects from 
other plants, and survey the most salient 
features presented by the fungi. 
Fungi, like the flowering parasites above 
mentioned, have descended from green 
ancestors, but it is among the lower ranks 
of the vegetable kingdom that their origin is 
to be sought. It is tolerably certain that the 
class of fungi, as we know them to-day, repre- 
sent a number of not very closely related 
families, and that these have descended from 
more than one chlorophyllous algal stock. 
There is no reason, therefore, to think that 
their vegetative structure has undergone 
very important alteration in the direction of 
simplicity. It would probably be more in 
accordance with facts to say that it has never 
emerged from a primitively simple type of 
organisation. 
The body of a young, actively growing 
fungus consists entirely of simple tubular 
threads, or hyphae, which, in the majority of 
species, are partitioned by cross walls. These 
