Fig. 45 Cladophora. A, plant with sporangia. B, shoot of Aega- 

 gropila holsatica bearing rhizoids. C, stolon of Ae. holsatica. D, 

 rhizoids of Spongomorpha vernalis developing storage cells at the 

 apices. (A, after Oltmanns; B, C, after Acton; D, after Fritsch.) 



shape is brought about by a continual rolling motion over the soil 

 surface under the influence of wave action, and hence the 'ball' 

 forms are found near the shore whilst the 'thread' and 'cushion' 

 forms are to be found farther out in deeper water where there is less 



58 



