354 Wager: The Study of Fungt. 
In recoiding and comparing the species found in different 
districts, many interesting lines of investigation would be 
opened up. The geographical distribution of the Fungi, and 
their relationships to one another and the environment have 
been scarcely considered. Many who are experienced in the 
field, could no doubt give a fairly complete list of the species 
to be found in the various plant associations such as a meadow, 
a moor, an oakwood, beech wood, pine wood, marsh, etc., but 
this has never, so far as I am aware, been systematically done. 
How do the species in any given locality vary from year 
to year? What are the dominant species? What species 
occur only rarely ? What species are common-to more than 
one formation ? How do the species vary in a given locality 
according to the seasons? In a pine wood, an oak wood, or 
any other formation, how do the species follow each other from 
one season to another? How is their succession connected 
with the environment, and what are the conditions under 
which they appear? The nature of the soil, the- water con- 
tent, the temperature may all take a part in determining the 
species which may prevail at any given time. What again is 
the actual effect of a long dry summer followed by a wet autumn 
or of a wet summer and a dry autumn, or of the various other 
combinations and samples of weather which is such a con- 
spicuous feature of our climate ? We have some rough idea 
of the effects of these various factors, but we have no precise 
or definite information concerning them. A complete answer 
to such questions doubtless demands elaborate investigation, 
but even rough and ready methods would be valuable at the 
present stage, and would give us a clue to the more elaborate 
methods which it may be necessary to adopt later, to arrive 
at a satisfactory solution of the problems. 
In common with all other plants the nutrition of the Fungi 
and the development of their form and structure are to some, 
extent, controlled by external conditions. What are the 
controlling forces, and how do they act? The Fungi are 
extremely variable. To what extent may the variations be 
brought. about in response to external stimuli? What are the 
factors in all these changes of form and colour which are 
exhibited by so many of the Fungi? What are the limits of 
variation in size of any given species ? How is the variation 
in colour associated with the environment, the presence of light, 
moisture, food supply 2?) To what extent have gravity, light,’ 
temperature, moisture and variation in nutrition the power 
to cause a modification of the Fungus form ? 
Gravity plays an important part in maintaining the pileus 
in the horizontal position which is, according to the researches 
of Professor Buller, necessary for the efficient distribution of 
the spores In some species light appears to be of importance 
Naturalist, 
