PONDWEEDS AND PONDWEEDLIKE PLANTS 

 OF EASTERN NORTH AMERICA 



This is the first of a series of publications on the field ident- 

 ification of the marsh and water plants of eastern North America. It 

 describes twenty-seven pondweeds and thirteen non-pondweeds. Current 

 manuals describe several other kinds of pondweed which I consider to 

 be only variations of those treated here. 



Pondweed seeds and rootstocks are among the most important water- 

 fowl foods. Pondweeds are common in freshwater lakes, ponds, streams 

 and marshes from Manitoba to Newfoundland and south to New Jersey and 

 Iowa. A few kinds grow farther north and south; a few grow in the 

 fresh and brackish waters of coastal bays, rivers and ponds. 



Pondweeds have limp underwater stems which are from a few inches 

 to a few feet long. These stems are often branched. Some stems come 

 up in spring from rootstocks that live through the winter, some from 

 winterbuds, some from seeds. Near the top of the stems of some kinds 

 are oval or oblong floating leaves. Usually these stems have under- 

 water leaves, too. Looking quite different, the same kinds sometimes 

 have only underwater leaves. Other kinds have only oval or narrower 

 underwater leaves. 



In summer, pondweeds produce small greenish or brownish flowers. 

 In most kinds these are packed together in oblong or ball-like heads. 

 In bloom the upper heads stick out of water an inch or two, but by the 

 time the naked seeds ripen most of the heads are back in the water. 

 The non-pondweeds have very different flowers and seeds. 



In order to see some underwater plants clearly a person has to 

 bring a stem close to the surface of the water or even take it out. 

 Out of water the leaves often slump together. They can be separated 

 again by laying the plant flat and gently splashing water over it, or 

 by putting it in shallow water in a dish. 



The pictures show plants of average size and shape. Those of the 

 upper part of stems, with their leaves and seed heads, are one-half 

 life-size; those of separate heads and leaves are twice life-size. 



