184 BOTANICAL GAZETTE. [ August, 
peculiar to oaks, and, as the synonymy of the species pay 
confused, the exact number of fungi known on all our oa : 
can-not be given exactly. On Quercus alba fifty-seven Wi 
on Q.. tinctoria forty-six species are reported, about a qua 
_or possibly a third, of which are probably peculiar to tho 
species. 
: We can start with the postulate that vegetable parasites 
must have originated at an early epoch and must have pail 
derived from non-parasitic forms. What forms? pee i 
enter upon the field of pure speculation. It can ‘har is 
supposed that we shall ever know what was the earliest ne 
of life. It may have been some ailiabitors structure W 
Protococci are simple green cells which multiply by ahs 
into two, and so on, and which, at times, also produce di- 
their interior zoospores which escape and’form new IB 
viduals, ; risen 
How other chlorophyll-bearing plants might have a can 
from Protococci we can not stop to consider, and we i208 
only touch upon the possible origin of the colorless parasits 
we . » é . cci - 
A . vegetation consisting of simple forms like Protoce 
i : { not 
once established, there is no reason why there might 
quickly have followed parasites of the order Chytridiace® 
the species of which abound at the present day 1n both : a 
and fresh water. The simple forms of the order consis nae 
colorless cells which produce in their interior colorless k ed 
Spores, which escape and attach themselves to submetgé 
plants and animals. ipl We 
The step from Protococcus to Chytridium is slight. ie 
have only to Suppose that a Protococcus has acquire’ ae 
power of attaching itself to other Protococci or 10 no 
mals and has gradually lost the chlorophyll, which iieke 
longer of service to a plant in a position to absorb chenaee 
ment directly from living organisms. Other natural cha The 
would be the development of processes for attachin 
™ 
