Plate XVII. 



Fig. 1. Sargassicm süiquosioii J. Ac. 



The upper part of a sterile frond, witli tlie peculiar ampullated 



leaves. 

 Figs. 2, 3. Sargahsimi assimila var. stipulata. 



2. A full-grown lateral branch from near the middle of a frond. 



3. Lower portion of the same frond. In both figs. 2 & 3 the ends 

 marked with x are continuous with soni« intervening si)acfc;. 



Fig. 4. Sargass'iim vuhjarc var. Jbliosissinmui J. Au. 



A receptacular ramulet. Ca. x 2^. 

 Fig. 5. Sargassuoii vulgare var. linear if oliui it J. Ac. 



a. A part of a branch with a fertile lateral branch. 



b. A receptacular ramulet. Ca x 3. 

 Figs. 6-10. Sargassîmi sagamiaimm. 



6. The knotty root. A young branch and a part of a well -grown 

 branch are shown in the figure ; other branches are all left out. 



7. Middle portion of a well-grown branch with two lateral branches. 

 The end marked with x is to be connected with the same-marked 

 end in the preceding figure. 



8. Lower portion of a full-grown branch. 



9. Basal portion of a full-grown lateral branch. 



10. A young sterile branch with the secund leaves. 

 Figs. 11-16. Sargassu7n nipponicmn. 



11. Lower portion of a frond. 



12. Apical part of a principal shoot. 



13-16. Receptacular ramulets in various stages of development. 



