262 MORPHOLOGY. 



and influence the internal structure, but never can change the 

 destined form. Thus, consequently, the leaf is the form, deter- 

 minate in its growth, and therefore morphologically, which proceeds 

 from the fundamental element of the plant, the axis, indeterminate 

 in its growth, and therefore morphologically indeterminate : this 

 definition includes all foliar organs, and excludes all axes. 



I do not think that it will be possible, in the first place, to find a more 

 strict expression of the distinction between leaf and axis than is here 

 given, yet I feel deeply that it is very far from being the only correct 

 and sufficient one : but here again we require a much deeper penetration 

 into the history of development than up to this time has or could have 

 been attained (see Plate III., figs. 1 1 1 .). Progress will first become pos- 

 sible when we have resolved the whole process of formation in the leaf into 

 the history of the formation of its individual cells, which, as the most 

 difficult task in all Botany, will yet remain long unperformed. At the 

 same time it is not to be denied, that the distinction between leaf and 

 axis is the sole scientific basis for the whole morphology of the Phane- 

 rogamia. It has certainly been more easy to comprehend this since 

 Goethe's Metamorphosis of Plants has conjured up a presentiment of the 

 morphological unity of the law of formation, but little has yet been done 

 for the strict and scientific comprehension of the matter. As I have 

 already observed, the cause of this is the want of philosophical, especially 

 logical, exposition ; for it is not noticed that the obscure ideals of the 

 imagination must be elevated into conceptions capable of definition by 

 inductive method, to fit them for a properly scientific treatment. How 

 little our text-books fulfil this purpose has been already remarked. 

 Let us take another example : Link * says, " ' A leaf,' says Joachim 

 Junge, * is that which expands upward, or in length and breadth, from 

 the place at which it occurs, and the boundaries of the third di- 

 mension of which, that is. the inner and outer surface of the leaf, are 

 different from each other.' This definition excellently marks all foliar 

 parts." That this pretended excellent definition does not at all apply to 

 the parts of the flower (which certainly are foliar parts) is clear, but 

 it does not apply to any leaves of Pines, of Mesembryanihemum^ Sedttm, 

 Opuntia, nor to the scarious stipules of the Paronychiacece, &c. Link 

 says, further : " The main distinctive character of leaves is the position 

 beneath the buds. Every true branch originating from a bud," (yet 

 only from an axillary bud,) "is supported at its base by a leaf. . . but 

 all leaves do not support branches." How, then, does Link know that 

 these are leaves, when they are deprived of their principal distinctive 

 character? No science will be advanced in this way, but merely ground- 

 less chattering stereotyped. 



II. When the leaf emerges from the axis it is a little conical 

 body, the base of which gradually comes to occupy the entire cir- 

 cumference of the axis, a stem-embracing or amplexicaul leaf (f. am- 

 plexicaule) ; or it shares the circumference of the axis with one or 

 more other leaves, which have originated with it on the axis in the 

 same plane, whorled leaves (f. verticlllata) ; or, lastly, it is confined 

 to a small portion of the circumference, without any other leaves 



* Elem. Phil. Bot. ed. 2. vol. i. p. 410. 



