10 PLANT-LIFE ON LAND [ch. 



they are ? The eifort is in fact to reconstruct evolu- 

 tionary history. It is clear when once this general 

 problem is enunciated, its solution must involve 

 enquiry not only as regards form and structure, but 

 also as regards function with which form and structure 

 are so closely related. These questions expand 

 naturally into numerous cognate phases of enquiry, 

 such in fact as the various individual specialists have 

 made the subject of their detailed research. Thus, 

 while apparently driving lonely furrows, they are all 

 at work for a common end. But the field is so vast 

 that the casual onlooker may fail to grasp the general 

 scheme, by reason of visualising only that part of it 

 which happens to be nearest to him. He may see 

 perhaps a solitary investigator working in a way that 

 may seem trivial or unsatisfactory. But the doubts 

 of the critic may really arise from the fact that the 

 value of the work cannot be estimated without some 

 knowledge of its relations to the ultimate goal. On 

 the other hand, it must be confessed that it is not 

 every worker who understands the general scheme of 

 which his labour forms a part, however well he may 

 be carrying out his own particular research. And 

 furthermore, since there is seldom any master-hand 

 directing the efforts of individuals, some workers, 

 having a perverted idea of the general scheme, may 

 lay out their own investigations on mistaken lines, 

 and their labour may be in vain. This is the fate 



