,74 BOTANY OF THE LIVING PLANT 



condition .s only acquired in the course of the -dividual development^ 

 and is not shown by the ap.cal bud. This .s seen m the rh.zomes of 

 Acorns, where the apical bud shows a bilateral symmetry, w.th alter- 

 nate leaves But in the mature rhizome the two rows are shifted to 

 the uppir surface, giving a dorsiventral condition, with roots arising 



Fig. 130- 

 Successive sympodial shoots of C^ux. (After Figuier.) 



from the lower surface. In other cases again, and conspicuously in 



Fer^s the dorsiventrality is fixed already at the growing point, and 



fs no 'the mere result of any subsequent displacement of parts Thi 



"een in the Common Polypody, which has from the first distichous 



e^v spaced obliquely on the upper surface of the rhizome, while 



