THE ALGiE 



229 



Specialization of the apparatus for reproduction and differ- 

 entiation of gametes are always found to accompany progress 

 from the lower to the higher stages of plant development. 



294. Summary of the Green 

 Algae. — Green algse occur 

 almost all over the earth's sur- 

 face. They reach their highest 

 development in fresh water, but 

 there are many marine genera 

 and species, and one of the most 

 conspicuous of all the groups 

 is that which embraces the sea- 

 lettuce {Viva) and its allies. 



Fig. 158. End of a Main Shoot 

 of a Stonewort, Chara, 

 (About natural size.) 



Fig. 159. Part of a "Leaf" of Fig. 158. 

 (Considerably magniiied.) 



a, antheridium; u, oogonium. At the 

 right are a young antheridium and 

 archegonium. 



This plant is a familiar object, waving as it does from 

 rocks, piles, and wharves alongshore. Terrestrial genera 

 and species of green algae are not uncommon. 



