SUBMERSED AQUATIC 

 WEEDS 



Submersed aquatic plants are a cosmopolitan group, representing 

 a number of plant divisions and families. Plants grouped in the general 

 submersed category range from primitive forms to highly developed 

 flowering-type pondweeds that grow primarily in the water medium, 

 including some species that develop specialized floating or emersed 

 leaves and fruiting heads. A few representatives presented in this 

 section might better be designated as combination submersed-emersed 

 aquatic plants, but were included in this group because they are most 

 troublesome when growing in the submersed form. Many of these 

 plants are adaptable to wide variations in environment. The same 

 species are often found growing in widely diverse situations of water 

 temperature, quality, and velocity. Submersed aquatic plants often are 

 able to survive periods of adverse growing conditions. This is due 

 predominantly to prolific seed or spore production and the extensive 

 and varied development of specialized tissue for vegetative 

 multiplication. The submersed plants probably cause more trouble in 

 irrigation waters than all other types of aquatic weeds. Extensive 

 growths in distribution and drainage systems restrict the carrying 

 capacity of canals and choke trashracks and pump inlets. 



Some of the more common species of submersed plants found in 

 irrigation systems are described to illustrate the types that may be 

 encountered. Positive identification of some of these plants requires 

 close examination and the use of technical botanical references. 



