PLATE 17 



Pseudopringsheimia apiculata S. and G. 

 Fig. 1. A section through tlie thallus of a mature plant perpendicular to 

 the host. X 250. 



Fig. 2. A section through the thallus of a youug plant. X 250. 



Prasiola delicata S. and G. 

 Fig. 3. a-f. Series of different forms of plants. X 10. 



Viva vexata S. and G. 



Fig. 4. A group of plants showing different shapes and sizes. X 1. 



Fig. 5. A group of mature plants showing the presence of the parasitic 

 fungus, Guignardia TJlvae Eeed. X 3. 



Fig. 6. A cross section showing the presence of fungal hyphae in the medulla. 

 X 250. 



Fig. 7. A surface view. X 250. 



This plate is from Setchell and Gardner, Phyc. Gout. I, 1920, pp. 279-324, 

 pi. 22. 



[342] 



