This section is from the book "Harper's Guide To Wild Flowers", by Caroline A. Creevey. Also available from Amazon: Harper's Guide To Wild Flowers.
Family, Duckweed. The leaf (here called a frond) has a little cleft in its margin from which the small flowers spring. Generally there are three flowers, two of them consisting of a stamen only, one of a pistil only. The fronds taper to a point, and often several are connected in a sort of chain. Common in shallow ponds, ditches, and springs.
 
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