AN OUTLINE OF PIT YTOBtOLOG Y. 11 



upon Insectivora, fertilization and soed-disseniination, and 

 the student cannot possibly do better to prepare liimseH 

 for similar work than to study these classical models. 

 "We shall have much more to say upon this subject under 

 the special divisions to follow. 



• The training of the judgment, axiomatical for all good 

 scientific work, has a particular application to our present 

 more limited topic in connection with the nature of 

 adaptation. As we have seen, not all the characters of a 

 plant are adaptive. Some are simply inherited and of 

 little or no direct use ; and others are incidental to some- 

 thing else. The line separating inherited or genetic 

 characters from those adaptive or immediately useful, 

 is extremely shadowy and shifting, and the relationship 

 of the two is of the most varied degrees. In general, the 

 student may feel sure that the most superficial characters 

 — form, color, size, position, etc., are immediately adaptive 

 to readily-observable agencies, while the deeper seated 

 characters are either adaptive to more general agencies, 

 or are inherited and not now of vital importance. One 

 may obtain a rough measure of the immediateness of 

 adaptation by noting how far the given character runs 

 throughout the relatives of that plant. If only specific, 

 it is probably easily discoverable ; but if generic, or tribal 

 or ordinal, it becomes proportionally deep-seated and more 

 difficult to detect. But ever there comes in also the 

 third term of the life-equation, which is almost unknown, 

 hence making it so difficult to solve it to the fourth. 

 Heredity, environment, internal constitution are the three ; 

 use or reason for being is the sought-for fourth. 



Again, the student is often misled by what seems 

 to be adaptation, but in reality is not, which teaches that 

 conclusions cannot be safely drawn from a single line of 

 .observation. Thus the presence of the sexual organs 



