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annually contribute, to the population of rural Delaware, many 
 
hundreds of thousands of dollars. 
 
       The Marsh as a Treasure House: As a source of salt hay, and 
of food and shelter for muskrats, water-fowl, rails, and other 
 
birds, the marsh and its vegetation have been evolving over a very 
 
long period. To understand Justow these riches continue to exist, 
 
it is necessary to study certain relationships on the marsh. 
 
       To a botanist, every marsh has its own geography. Plants 
exist in belts that are governed by such factors as water-levels, 
 
tides, chemistry of the soil, etc. Starting at the wet end of the 
 
marsh, let us make an imaginary survey -- which anyone can duplicate 
 
in the field-- as far as the upland. 
 
       It will be seen that certain kinds of plants are found only 
in certain locations. In the tidal zone, for example, where the 
 
roots are frequently washed by salt water, we notice that there is 
 
a plant locally known as Cow Grass (Spartina alterniflora), which is 
 
an important food plant for both muskrats and water-fowl. This is 
 
found nowhere, except in salt zones. It may not exist for many 
 
yards as one goes higher on the marsh, except in low places that 
 
hold salt water. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
     B-39  Belts, showing Cow Grass (4), Salt Marsh Fleabane (1), 
           Cord Grass (2), Kink Bush (3) (indicated by marks on 
           print) on newly ditched marsh. 
 
       The next belt found on the marsh is a pale, gray-green plant 
known aS Spike Grass (Distichlis spicata), which is only found in 
 
such a zone and in alkaline soil in the interior. (That word 
 
alkaline is important for future reference.)