128 MORPHOLOGICAL DEVELOPMENT. 



sea- coast has abundant examples of stunted trees which, like 

 the one shown in Fig. 199, have been made to deviate from 

 their ordinary equal growth on all sides of a vertical axis, to 

 a growth that is equal only on the opposite sides of a vertical 

 plane directed towards the wind s eye. 



From among vegetal aggregates of the third order, we have 

 now only to add examples of the entirely asymmetrical form 

 that accompanies an entirely irregular distribution of inci 

 dent forces. Creeping plants furnish such examples. They 

 show us, alike when climbing up vertical or inclined surfaces 

 or trailing along the ground, that their branches grow hither 

 and thither as the balance of forces aids or opposes ; and the 

 general outline is without symmetry of any kind, because 

 the environing influences have no kind of regularity in their 

 arrangement. 



220. Along with some unfamiliar facts, I have here set 

 down facts that are so familiar as to seem scarcely worth 

 noting. It is because these facts have become meaningless 

 to perceptions deadene:! by infinite repetitions of them, that 

 it is needful here to point out their meaning. Not alone for 

 its intrinsic importance has the unlikeness between the 

 attached ends and the free ends been traced among plants 

 of all degrees of integration. Nor is it simply because of the 

 significance they have in themselves, that instances have been 

 given of those different varieties of symmetry and asymmetry 

 which the free ends of plants equally display : be they plants 

 of the first, second, third, or any higher order. Neither has 

 the only other purpose been that of showing how, in the radial 

 symmetry of some vegetal aggregates and the single bilateral 

 Eymmetry of others, there are traceable the same ultimate 

 principles as in the spherical symmetry and triple bilateral 

 symmetry of certain minute plants first described. But the 

 main object has been to present under their simplest aspects, 

 those general laws of morphological differentiation which are 

 fulfilled by the component parts of each plant. 



