164 UNIVERSITY OF MISSOURI BULLETIN 



bacteria to dairying and to soil fertility, as well as to disease, 

 makes them one of the most important, economically, of all 

 the great groups of plants. 



But it should be again insisted that the subdivisions of 

 the science of pure botany mentioned above are entirely ar- 

 tificial. The facts of structure are wholly without meaning 

 except in the light of function. That a leaf is a flat, expanded 

 organ, for example, is of no significance to us when divorced 

 from its green color and the need of exposing to sunlight as 

 great a surface as possible of green tissue. The process of 

 taking in water must remain a mystery to one who is ignorant 

 of the structure of roots. Goebel has even defined morphol- 

 ogy as "that which is not yet understood physiologically."* 



Ecology is the common meeting ground of physiology and 

 morphology. The classification of plants (systematic botany 

 or taxonomy) cannot be studied apart from external anat- 

 omy, and among the bacteria where structure is extremely 

 simple, the forms are classified on the basis of physiological 

 behavior. Thus it is evident that, just as the various knowl- 

 edges are artificial divisions, representing only different points 

 of view, so, also do the subdivisions of botany signify, not 

 so many well fenced fields, but meshes in a closely woven 

 network. They result from different points of departure, 

 or from placing the emphasis in different places ; but all tend 

 to the same ultimate goal, namely, the answering of the ques- 

 tion what is a plant? 



A study of the history of botany discloses well defined 

 epochs, each ushered in by some fundamental discovery. 

 Most important and fundamental of all was the gradual per- 

 fection of the scientific method, relieving botany, together 

 with all natural science, from the stumbling block of the 

 Aristotelian method of reasoning. As pointed out above, this 



*Goebel, K. The Fundamental Problems of Present Day 

 Plant Morphology. Science, N. S., vol. 22, p. 33. 1905. 



