Seasides and Strand Plants 
nearly horizontal; the men also tend to form an acute 
angle with the rope. The stem and roots of Zostera 
has a curious similarity to the tug-of-war rope, and one 
sees at once how well it is adapted to hold its place. 
All along the stem, at every 1 or 2 inches, are the 
flattish, grass-like leaves which may be 3 feet long, 
and are kept upright and waving in the water. These 
leaves have a water-pore at the tip (presumably to keep 
up the circulation of food material), but are without 
the stomata characteristic of ordinary leaves. 
The flowers consist of one stamen and one carpel, and 
about twelve of them are enclosed in a protective sheath. 
When ripe, the pollen is discharged into the water. 
The whitish pollen grains resemble tiny worms about 
3 mm. long (,8,th inch ; the length is about 250 times 
the breadth), and are unlike any other pollen grains, 
Being of the same specific gravity as sea-water, they 
float freely about; should they happen to touch the 
long stigmatic surface of a carpel, they wrap themselves 
spirally round it and so effect fertilisation. The fruit 
is supposed to be eaten by fish. , If so, Zostera marina 
has been successful enough, for it is found from the 
Mediterranean to the Baltic, in North America (Atlantic 
and Pacific Coasts), and in China and Japan.? 
These submerged meadows are of some importance, 
for they tend to prevent the continual shifting of the 
sand- and mud-banks, which of course is the first step 
in the formation of new land. How far they succeed 
in doing this has not as yet been discovered. 
When, however, such banks have been fixed in position 
and so raised by deposited silt that they are distinctly 
exposed at low water, a new development begins. 
Amongst the floating rubbish carried back and forward 
by the changing tides are certain round fleshy little 
bodies bearing minute flowers and fruits, 
159 
