PLATE 22 



Pseudopringsheimia apiculata S. and G. 



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

 the host. X 250. 



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



Prasiola delicata S. and G. 

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



Ulva 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 Ulvae Reed. X 3. Taken from Reed, 1902, pi. 15, fig. 1. 



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

 medulla. X 250. 



Fig. 7. A surface view. X 250. 



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