XI, C, 4 
Copeland: Natural Selection 
161 
not proved of any special value to its possessors, and is probably a more 
recent development. There are many other so-called adaptations in many 
other families which can be dealt with in the same way. Always the 
figures go to show that evolution of forms is on the average indifferent, 
and that these so-called adaptations are of no special advantage to their 
possessors.” 
Now, if we agree that the Rubiaceae with fleshy fruits are 
more recent than those with dry fruits, this alone might be 
responsible for the greater abundance of species with dry 
fruits, in spite of more perfect adaptation on the part of those 
with fleshy fruits. In reality, however, this does not hit the 
kernel of the matter. The fact is that the dry fruit is also an 
adaptation, just as much as is the fleshy fruit. One is adapted 
to one set of conditions, the other to another set, and the two 
sets of conditions may perfectly well be encountered at the same 
time and in the same place. A perfectly parallel situation is 
presented by the structure of the pileus of the Agaricales. As 
Buller has beautifully shown in the Pfetfer Festschrift, most 
of the species of Coprinus have one type of structure and beha- 
vior, while Psalliota and nearly all of the other Agaricaceae have 
a different type, the two differing in almost all possible details, 
even down to the finest, but both being recognized by Buller 
as highly and appropriately specialized, the two occurring side 
by side without the slightest prospect that either will drive 
the other out. 
It is important to each group of plants, for the sake of the 
completest possible success in holding what place it has and in 
spreading, that it occupy every available habitat, make use of 
every available means of dispersal, and make the most of each 
factor that will insure the reproduction of any of its members. 
The fact that some Rubiaceae are adapted to dispersal by the 
characters of their dry fruits does not make it at all a dis- 
advantage that related plants of the same family be adapted 
to the same end by the possession of fleshy fruit. The family 
is better off with two general methods than it would be with 
one general method. In each generation, the family as a whole 
is safer because every possible method is taken advantage of 
by some of its members. The members that scatter their seeds 
by the medium of fleshy fruits are, in this respect at least, out of 
competition with those that scatter their seeds by methods 
depending upon the dryness of their fruit. To this extent, the 
family can have more members and be more successful, because 
in this respect competition within the group is removed. 
