A WORLD IN THE WATER 99 



In a normal state they are attached to a rock, 

 the sides of a quay, or they will frequently 

 festoon the piles of a pier. One of the most 

 abundant is known as the Bladder Wrack {F. 

 vesiculosus), a plant which varies enormously, 

 according to the condition under which it is 

 growing, though its many-branched leaves are 

 generally of an olive colour. This species, as 

 indeed are many of the F^^ci, is very accom- 

 modating, and seems to get on equally well in 

 positions where the receding tide will leave it 

 high and dry for some hours, or farther out 

 from the shores where it is never entirely un- 

 covered. Its foliage is maintained in a float- 

 ing attitude in the water by means of air 

 bladders, which all children — and many grown- 

 up people too— love to " pop." 



At almost any time during the summer and 

 autumn it is possible to find the reproductive 

 organs of the Bladder Wrack at the ends of 

 certain branches of the leaves. To the naked 

 eye the collections appear hke so many nobs 

 with somewhat roughened surfaces. The actual 

 organs of reproduction arise in flask-shaped 

 hollows in these parts. In certain of these 

 cells the male bodies [spermatozoids) are pro- 



