OF LIVING FORMS; OR, MORPHOLOGY. 89 



when young (Fig. 16). It looks as if it had been 

 rolled up. But this is not the case ; it may easily 



be seen that it cannot be. 



Fig. 16. 



There has not been a flat 

 frond which could be curled 

 up. It grows into this form, 

 because the central part 

 grow&f while the ends are 

 fixed. With the increase of 

 the plant it becomes free 

 and uncurls ; but it has never 

 curled. The curling is an 

 appearance due to its growth. 

 Or let us take another 

 class of forms. The buds 



of plants almost always grow in the axils of the 

 leaves. It is not hard to see a reason for this. The 

 axil is the interval between the leaf and the stem ; 

 a kind of vacuity or space, into which the growing 

 tissues may most easily expand. All the rest of the 

 surface of the stem is covered in by the hard resist- 

 ing bark, but where the leaf separates this resistance 

 is diminished. It is the joint in the armour. So, 



Young Frond of the Male Fern. 



