Plate 20 



Figs. 1-6. Cladophora fracta (Dillw.) Kuetzing: various expres- 

 sions of the filaments; 1, habit of branching (diagram); 

 2 and 3, x 200; 4, x 100; 5, branch origin, showing 

 lamellations of wall, x 250; 6, old, 'winter' stage, x 200 



Fig. 7. Cladophora fracta var. lacustris ( Kuetz. ) Brand, x 500 



Figs. 8, 9. Cladophora glomerata ( L. ) Kuetzing: 8, portion of main 

 filament, x 75; 9, habit of branching, x 350 



[700] 



