2o6 



PHAEOPHYCEAE 



third sterile branch which is also reduced to an air-bladder, but all 

 the subsequent branches are fertile and finger-like in appearance. 

 The plants are attached by means of a more or less irregular, warty. 



Fig. 138. Sargassum. A, S. filipendula ( x 0-45). B, base of plant. C, escape of 

 sporangia each with eight nuclei (X40). D, seedling at rhizoid stage (x 105). 

 E-G, stages in branching, 6". Thunbergii ( x 0-22). a = main initial, ai = branch 

 initial, ^2 = secondary branch initial. (A, B, after Taylor; C, after Kunieda; 

 D, after Tahara; E-G, after Oltmanns.) 



solid, parenchymatous base or else numerous stolon-like structures 

 grow out from the main axis and anchor the plant. The genus, 

 which is principally confined to tropical waters, is a very large one 



