308 MINNESOTA BOTANICAL STUDIES. 



Material in the fruiting condition was not available, and there- 

 fore observations on the reproduction will be made at a future 

 time. According to Kjellman the sori are found as oval areas 

 spread over that portion of the lamina where the old lamina 

 merges into the new. The sporangia do not differ from those 

 of other Laminariaceae. 



Bibliography. 

 Kjellman, F. J. Beringhafvets Algflora, page 46, 18S9. 



Explanation of Plate XLVII. 



1. Photograph of Laminaria bullata. 



2. Diagram of haptere showing the direction taken by the cells of 

 the cortex. They run in straight lines towards the apex of the haptere, 

 but bend outward at the sides. 



3. Longitudinal section of haptere showing epidermal cells, hypo- 

 dermal cells, cortex and a mucilage duct. 



4. Cells near apex of haptere, as seen in longitudinal section. 



5. Cells from side of haptere showing curving direction of cortex 

 cells. Longitudinal section. 



6. a. Diagram of lower hollow portion of stipe. 

 b. Diagram of upper portion of stipe. 



7. Diagram of longitudinal section of stipe, a, epidermal region; 

 b, mucilage duct; c, cortex; ^strengthening cells; e, pith web. 



8. Cross section stipe, showing cuticle, epidermal and hypodermal 

 cells, mucilage ducts and cortex cells. 



9. Epidermal and hypodermal cells of stipe. Longitudinal section. 



10. Strengthening cells of cortex of stipe. Cross section. 



11. Strengthening cells of cortex of stipe. Longitudinal section. 



12. Pith web of stipe. Longitudinal section. 



13. Pith web of stipe. Cross section. 



14. Cross section of lamina showing cuticle, epidermal cells, hypo- 

 dermal cells, mucilage duct and cortex cells. 



15. Cross section of lamina showing strengthening cells and origin 

 of hyphre of pith web. 



16. Longitudinal section of lamina showing same points as 15. 

 17- Pith web of lamina in longitudinal section. 



