﻿Nichols: The vegetation of Connecticut 179 



ing two sorts of leaves, viz., submersed and floating; but the 

 latter type is seldom formed on plants growing in water more 

 than five feet deep. Flowers likewise are usually suppressed, 

 except in shallow water, reproduction being accomplished solely 

 by vegetative means. Other plants frequently present in con- 

 siderable abundance in the pondweed association are Najas 

 flexiUs, Vallisneria spiralis, and Elodea canadensis. The lack 

 of dependence of many of these water plants on the sexual 

 methods of reproduction is well exemplified by the latter species. 

 Introduced into Europe from America about 1836, this "Wasser- 

 pest" has become widely spread over that continent, notwithstand- 

 ing that it has never been observed there in fruit. Fig. 4 shows a 



ViG. 4. Submersed aquatics from 



Twin Lakes. Salisbury. The plants were 







are' as follows: i. Polamogeton pectinaii 



is; 2. P. lucens; 3. P. natans; 4. P. ampU- 



f alius; 5. P. heterophyllus; 6. Char a s 



,p.; 7. Ceratophyllum demersum; 8. Elodea 



Canadensis; 9- Sparganium minimum; u 



,. Eleocharis Robbinsii; 11. Utricularia inter- 



representative collection of aquatic plants from a lake in northern 

 Connecticut. The majority of such plants have roots and grow 

 attached to the bottom, but there are a number of forms, notably 



