112 THE PHENOMENON OF 



deviating directions only in its branches. Thus it gives 

 the plant its basis and connection with the inorganic 

 soil, and especially supplies that material, by the assimi- 

 lation and subordination of which the entire plant 

 becomes realised. In correspondence with its direction 

 of growth, it forms a contrast to the total ascending de- 

 velopment of the plant ; it therefore has no metamorphosis. 

 For the same reason it is devoid of leaves, these being 

 the steps in the course of the metamorphosis. 



Thus, then, stem, leaf, and root present themselves as 

 essentially different parts of the vegetable organism, as 

 its fundamental organs depending on the difference of 

 the directions of development of vegetable life. The sure 

 and exact distinction of these forms the basis of Morpho- 

 logy. That the study of the lower plants leads us to 

 structures in which the different directions of vegetable 

 life do not appear clearly distinguished, is no reason why 

 we should deny their essential and inconvertable differ- 

 ence when they present themselves really separated, as is 

 almost everywhere the case throughout the higher classes 

 of the Vegetable kingdom. 



Leaves and stem form together, as above remarked, 

 one whole, opposed to the root j if we regard the leaves as 

 rays, the stem forms the centre, necessary to the idea of 

 the rays ; if we regard them as waves, the stem represents 

 the level on which the undulations originate, forming the 

 troughs between the waves : a mode of viewing the phe- 

 nomena suggested by the theory of the arrangement of 

 leaves. Not only in the fully-developed leaf, do we see that 

 it is not sharply cut off from the stem, but runs gradually 

 into it, as shown in the formation of the pulvinus, in decur- 

 rent margins, &c. : this is indicated even in the earliest 

 appearance of the leaf, primarily a scarcely distinguishable 

 papilla, extending laterally into a little ridge (running back 

 as it were into the stem), the papilla sinking down outside 

 (below) quite gradually into the stem. How the leaf is 

 really formed, how it takes its first origin in the stem, and 

 by growth emerges from this, is a problem which the 



