10 5 5 5 1 1 1 159 10 4 5 4 4 4 4 3 2 3 3 260 10 5 5 4 4 5 5 2 2 3 3 261 10 5 5 2 4 4 4 3 2 4 4 3 1 5 5 3 0 5 3 4 262 10 5 5 5 4 5 5 3 2 4 4 3 1 3 5 3 0 5 1 1 2control 0 0 0 0______________________________________ in a second test the number of plants used in the test was increased to a total of six and the test was carried out as follows four of the plants to be used in the test namely florida elodea southern naiad eurasian milfoil and cabomba were prepared by cutting four inch terminal stems and burying the lower one inch of each stem in a mixture of sterilized sand clay loam soil 50 50 in plastic 5 oz drinking cups the drinking cups containing the plants thus prepared were placed in 1 gallon wide mouth jars two weeks prior to testing each jar was filled with water to the lower edge of the rim the volume then being equal to approximately 3500 ml of water the water used was dechlorinated city water there were then added to the top of the water in each jar a four inch length of coontail ceratophyllum demersum and approximately 60 duckweed plants lemna minor l in addition to promote the.