Fig. 1 17 Cystoseira. A, C. ericoides plant ( x |). B, portion of same 

 enlarged ( x 4-5). C, germling. D, same, rather older. E, diagram to 

 show nature of branching in C abrotanifolia. (A, B, after Newton; 



C-Ej after Oltmanns.) 



Cystoseiro-Sargassaceae 



SARGASSACEAE:C3^5^05ezra(rv5^05 bladder; s^zVa, chain). Fig. 117 



The much-branched perennial thallus is either cylindrical or 

 compressed and arises from a fibrous woody holdfast which has 

 more or less the structure of a conical cavern. The primary branches 

 arise from the main stipe towards the base and divide above into 

 filiform branches and branchlets, but when the latter do not 

 develop very far one gets what is known as the 'erica' and 'lyco- 

 podium' types, so called because of their resemblance to members 

 of those genera. Seriate rows of small air vesicles may be inserted 

 in the branches, and when this occurs the row of vesicles must be 

 regarded as a modified branch. On the approach of the dormant 

 season some species shed a considerable proportion of the branch 

 system so that the plant may appear very different. The plants are 

 monoecious or dioecious, the conceptacles being borne in terminal 



208 



