PLATE 10 



Prasiola boreaUs Reed 

 Fig. 1. A group of "n-hole plants infested by the parasitic fungus, Guignardia 

 alaskana Eeed. X 3.5. 



Fig. 2. A cross section of the frond. X 375. 



Fig. 3. A surface view at the margin of the frond showing the grouping 

 of the cells. X 285. 



Figures 1-3 are from Eeed, Two new Aseo. Fungi, 1902, pp. 141-16-i, pis. 

 15, 16. 



CollinsielJ^ tubercuJata S. and G. 



Fig. 4. Habit sketch of a group of plants. X 4. 



Fig. 5. A vertical section through one of the fronds. 



Fig. 6. Dissection of a part of the vertical section which has been treated 

 with Chloriodide of Zinc to show the branching. The cell contents are much 

 shrunken. 



Fig. 7. A tangential section at the surface to show the division planes. 



Fig. 8. A terminal cell showing a diminished chromatophore and two pyre- 

 noids. 



Fig. 9. A terminal cell showing the vacuolated appearance of the chromato- 

 phore. 



Fig. 10. A young terminal cell showing a complete parietal chromatophore 

 and one pyrenoid. 



Figures 4-10 are from Setchell and Garder, Alg. N.W. Amer., 1903, pp. 165- 

 418, ph 17. 



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