The Stoneii'orts 



137 



The stone-worts (Characece). — This group is well repre- 

 sented in freshwater by two common genera, well known 

 to every biological laboratory student, Char a and 

 Nitella. Both grow in protected shoals, and in the 

 borders of clear lakes at depths below the heavy beating 

 of the waves. Both are brittle and cannot withstand 



Fig. 55. Nitella glomerulifera. 



wave action. Both prefer the waters that flow off from 

 calcareous soils, and are oftenest found attached to a 

 stony bottom. 



The stoneworts, are the most specialized of the fresh- 

 water algse: indeed, they are not ranked as algae by 

 some botanists. In form they have more likeness to 

 certain land plants than to any of the other algae. 



