2 DIVISIONS OF SCIENTIFIC BOTANY 



life," but always in the sense that the exactness of the knowledge 

 of life-manifestations adds nothing to the causal mechanical expla- 

 nation of "life" itself. 



To morphology in the above sense belongs the description of the 

 form, size, arrangement, and outer and inner numerical relations of 

 the plant-body ; therefore anatomy is a part of morphology in the 

 wider sense. Usually, however, anatomy (inner form-relations) is 

 distinguished from morphology in a narrower sense (outer form- 

 relations). Thus limited, morphology forms one of the fundamental 

 principles underlying our present system of classification. 



Let us now return to the two main divisions of our science. A 

 few examples will make clear to the novice how morphology may 

 be distinguished from physiology, but that a complete and compre- 

 hensive knowledge of the plant necessitates a combination of the two. 



"When an investigation has for its purpose the explanation of 

 the cause of development of the woody cell-wall, then it concerns 

 itself with a function, in this special case a function of nutrition ; 

 this is therefore physiology. If one makes a microscopic compari- 

 son of one wood with another and seeks to find the similarities or 

 dissimilarities of the tissues, then no functions are involved and 

 the study is morphology (anatomical morphology). If one seeks 

 to find the relation of anatomical differences to the environment 

 (as a rule this relation is considered from a teleological stand- 

 point), then we must of necessity concern ourselves with phys- 

 iological processes. If we seek after the conditions which cause 

 plants to turn green, then the study is purely physiological : we are 

 solely concerned with energies. If, with the aid of the highest 

 magnifications, the finest structure of chromoplastids (chlorophyll 

 bodies) is studied in order to describe them more correctly, we are 

 concerned only with morphology. Development, for example, em- 

 bryology, belongs to morphology. To study, describe, and repre- 

 sent graphically, the successive stages of embryonic development 

 lies wholly in the domain of morphology. If one, however, makes 

 a study of the wall of the ovum in order to determine experimen- 

 tally what forces eventually determine the position of the first 

 septum, then we are again in the domain of physiology. If a 

 minute description is given of the various cell-forms found in the 

 stem, where, for example, the thick-walled cells occur, the form 

 of the thickenings, etc., then we are concerned with morphology. 

 If, however, one seeks for the significance of this or that cell- 



