Biological Survey — Oswego Watershed 243 



Appendix XII 

 Vegetation of Cayuga and Seneca Lakes 



W. C. MUENSCHEE 



The plant life of a lake is limited to that part of the water 

 which is penetrated by the sunlight. Aquatic vegetation consists 

 of two general types of plants: (1). The attached plants consisting 

 of the larger "pondweeds" which often form extensive weed beds. 

 (2). The microscopic free-floating plants (phytoplankton) 

 usually unobserved unless they are present in enormous numbers 

 when they produce the so-called "water bloom." 



The attached plants occur in shallow lakes or in the shoal waters 

 of deeper lakes often forming extensive weed beds. The most 

 common kind of weed beds in Cayuga and Seneca lakes consist of 

 large submerged plants that are rooted on the bottom, such as 

 "pondweed, " Potamogetons sp. and eel-grass, Vallisneria sp. etc. 

 Among these larger plants smaller plants are often so abundant 

 that the weed bed consists of a very dense tangled mass of vege- 

 tation which may or may not reach the surface of the water. 

 Attached to the stems and leaves of these larger* plants are in- 

 numerable smaller plants, algae and diatoms, many of which are 

 seasonal. Sometimes they completely cover the larger plants. 

 In Cayuga and Seneca lakes these weed beds are practically 

 limited to the water which is between 5-15 feet in depth. Another 

 type of weed bed common in Cayuga and Seneca lakes consists of 

 stoneworts or "grass," species of Chara and Nitella, covering 

 sometimes extensive areas of almost pure stands. In the shallow 

 water these plants usually have numerous diatoms and small algae, 

 or even larger filamentous algae, attached to them. The beds of 

 Chara occur in water from a few feet deep to a depth of about 

 20 feet. Nitella was observed only rarely in water less than 10 

 feet deep but more commonly in water from 15 to 25 feet deep. 

 In a few places, notably at the north end of Cayuga lake, at 

 Canoga marshes, and to a less extent at the south end of Cayuga 

 lake and Seneca lake cat-tail marshes occur in which the predom- 

 inating species is Typha angustifolia, Along the outer margin 

 of the cat-tail marshes other emersed plants such as rushes. 

 Scirpus a cuius and 8. americanus, may extend over considerable 

 areas of shallow water. 



The attached plants, and the smaller plants such as diatoms 

 and algae growing among them, form one of the principal primary 

 sources of food for fish and other animals living in a lake. Some 

 of the larger plants may furnish food or shelter for certain fish 

 or other animals that are eaten by fish. Some of the algae are 

 eaten directly by fish and other animals. Most of the larger 

 plants act as supports on which myriads of smaller plants, algae 

 and diatoms, and also many smaller animals may grow to furnish 

 food for other organisms. When the weeds die they decompose 

 and add to the organic matter in the water or the ooze on the 



