RELATION OF LEAF TO SHOOT-AXIS. 



39 



The interdependence of the leaves and their shoot-axes is made especially 

 clear at the growing point of the shoot, where it is easy to see that the leaves 

 are, fundamentally, only protuberances of the substance of the shoot-axis itself; 

 outer and inner layers of the tissue of this form protuberances, the tissues of which 



Fig. 29 DiaErrani of a dicotyledonous plant. / and // embryonic stages ; /// after germination, c. f cotyle- 

 dons ; TV, w' roots ; A hypocotyiedonous segment of shoot axis J 5—5"' leaves ; &, k' buds. The growing points 

 are shaded black, the parts becoming elongated grey. 



are from the first, and during the whole duration of life of the leaf, in complete 

 continuity with the tissue-systems of the shoot-aws. A root is connected with its 

 mother-root, or with the stem from which it arises, as something extraneous, like a 

 parasite which has first to establish its connection with the mother-organ. The leaves 



