STRUCTURE 203 



without the microscope the difference between one of 

 them and a tree or shrub is quite obvious. When cut 

 across they are seen to consist of a nearly homogeneous 

 substance of the consistency of soft gristle. But it must 

 be noted that these sea-weeds often reach a high degree 

 of differentiation, reminding one of the structure seen in 

 the higher plants. 



