VALUE OF AQUATIC PLANTS IN POND CULTURE. 
BY MR. C. K. GREEN. 
Two years ago at the request of the Commissioner of Fish 
and Fisheries the United States Agricultural Department de- 
tailed a skilled botanist to make a collection of the aquatic plants 
at Fish Lakes Station, Washington, D. C., and classify them. 
It was known that the ponds were rich in water plants and 
it was the idea of identifying the different kinds and ascertain- 
ing the habits and manner and growth of each, especially those 
which were most abundant, that the request was made. 
The city of Washington being recognized as a sort of botani- 
cal center, it is probably as favorable a location as could be 
selected for acquiring general information on the subject. The 
Fish Lakes Station has been called upon at various times to fur- 
nish aquatic plants for other stations. Some of the varieties 
are of great value both as oxygenators and food producers for 
the young fish; others, however, while undoubtedly possessing 
more or less merit in these respects, make such excessive growth 
and involve so much labor to remove them that their introduc- 
tion to other waters is not advisable. In all fifty-eight kinds 
were collected and classified, including those which are semi- 
aquatic, requiring a great deal of moisture but not submerged, 
growing about the edge of the ponds. ‘The two varieties which 
are the least desirable and cause the greatest amount of labor are 
Marsilea quadrifolia, the water clover, and Potamogeton pecti- 
natus, the fennel-leaved pond weed. The Marsilea, I am in- 
formed, was introduced many years ago by Prof. Baird and pro- 
cured originally from Texas. It presents a handsome appear- 
ance, growing on long stems, having a clover-like leaf and at 
certain stages a mass of it looks hke a well kept lawn. I have 
been unable to discover that it possesses valuable food producing 
qualities but the chief objecton to it is that it forms a net work 
of roots and grows so thickly that unless taken in early growth it 
is necessary when mowing, to cut if in chunks in order to lft it 
out with pitch forks. It apparently does not grow in water 
exceeding two feet so that it can be gotten rid of to a certain 
extent by deepening the pond. 
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