LHE PLANTS OF THE SEA. 51 
Another product of the sea is the marine zostera, a remarkable 
plant with large ribboned leaves of a dark-green. This plant is 
not a true alge. It belongs to the Mazadacew, the pond-weed 
family. They have very slender roots and attach themselves 
to the moving sands. They possess true flowers, although they are 
small. The zostera is employed in many places for mattresses and 
cushions, and for packing. In Holland, at the entrance of the 
Zuyder Zee, they use it under the name of wer for the construc- 
tion of dykes. 
Truly we must be struck with admiration when we reflect on 
the enormous masses of marine vegetation which every tide and 
every storm casts up in heaps on every shore, throughout every 
year and month and day, without appearing in the least to lessen 
the quantity which clothes the ocean bed. 
