The Philippine Journal of Science, C. 'Botany. 
Vol. VIII, No. 1, February, 1913. 
FACTORS INFLUENCING FUNGUS SUCCESSION ON DUNG 
CULTURES 
By William H. Brown and Paul W. Graff 
{From the Botanical Section of the Biological Laboratory, 
Bureau of Science, Manila, P. I.) 
The phenomenon of succession, or the gradual replacement of 
one association of plants by Another, is of widespread occurrence 
and probably effects the distribution of almost all kinds of plants. 
Owing, perhaps, to the greater prominence of the vascular plants, 
the phenomenon has been studied chiefly in connection with these ; 
but it is by no means confined to them. It is a well-known fact 
that a number of fungi occur in a rather definite succession on 
horse dung when placed in a moist chamber. The first to appear 
usually belong to genera of the Mucoraceae. These die down and 
are followed by a variety of forms which vary with the conditions. 
In Manila this stage is usually represented by the genera Oospora, 
Botrytis, Sordaria, and others in less quantity. After this several 
species of Coprinus usually appear and may continue to produce 
fruit bodies for a considerable period. The succession is fre- 
quently much more complicated than that outlined above. 
Successions of flowering plants are frequently due to geologic 
factors such as the weathering or erosion of the soil. In other 
cases, the primary causes of a succession consist of changes in 
purely physical factors produced by its first members. Exam- 
ples are the increasing of the water-holding capacity of soils by 
the accumulation of vegetable matter and the binding of wind- 
blown sand. It would seem evident that neither of the above 
classes of factors could be operative in the case of the succession 
here considered. 
There are, however, a number of theories which are frequently 
advanced in explanation of the succession of vascular plants ; and 
which, on theoretical grounds, might be considered as possibly 
applicable to successions such as the one described above. Some 
of the most prominent of these may be mentioned. The death 
of the first plants of a succession is frequently caused by the 
competition of those representing a later stage. In this case the 
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