CHAPTER III. 



MORPHOLOGY OF THE 

 EXTERNAL CONFORMATION OF PLANTS. 



Sect. 20. Difference between Members and Organs \ Metamorphosis. 



— The parts of plants which are ordinarily termed their Organs, very various in 

 their form and serving different physiological purposes, may be considered scien- 

 tifically from two difTerent points of view. The question may be asked at the 

 outset — How far are these parts adapted, by their form and structure, to perform 

 their physiological work ? In this case they are regarded from one side only as 

 instruments or organs, and this mode of regarding them is itself a part of physiology. 

 Or else these relationships may, for the time, be completely put aside, and the 

 question may be kept out of consideration what functions the parts of the plant 

 have to fulfil, and the only point kept in view may be where and how they arise, 

 in what manner the origin and growth of one member are related in space and 

 time to those of another. This mode of regarding them is the morphological 

 one. It is obvious that this mode is as one-sided as the physiological ; but 

 investigation and description require, here as everywhere else in science, abstractions 

 of this kind ; and they are not only not hurtful, but even of the greatest assistance 

 to investigation, if the investigator is only clearly conscious that they are abstrac- 

 tions. 



In this chapter we shall concern ourselves exclusively with the morphological 

 consideration of the parts of a plant. 



But before we proceed to a more minute investigation, it will be useful to get a 

 somewhat more exact comprehension of the relationship between the physiological 

 and the morphological view. 



Morphological investigation has led to the result that the infinite variety of the 

 parts of plants, which in their mature state are adapted to altogether different 

 functions, may nevertheless be referred to a few Original forms ^ if regard is paid 

 to their development, their mutual positions, the relative time of their formation, 



^ Nageli und Schwendener, Das Mikroskop, p. 599. Leipzig 1867. — Hofmeister, Allgemeine 

 Morphologic der Gewachse, sect, i, 2. Leipzig 1868. — Hanstein, Botanisclie Abhandlungen aus 

 dem Gebiete der Morphologic u. Physiologic, Heft I. p. 85. Bonn 1870. 



