794 The American Naturalist. [September, 



always appear above water, and consequently it occurs only 

 upon rather shallow shores. 



The Lemnacete are represented in the lakes by Lemna tri- 

 sulca, L. minor and Spirodela polyrhiza, none of which make any 

 attempt to grow in the bog. 



Eriocaulon septangulare is one of the few plants that are com- 

 mon to the lake and the moor, in fact, it is about the only one. 

 Whether it grows upon sand in a few inches of water, or upon 

 the soft mud in the newest portions of the moor, it seems 

 equally at home. I have found it growing in four lakes in the 

 county, but never saw it in a swamp where. there w^as no lake. 

 Paine says (Cat. of Plants of Oneida Co.), of the distribution of 

 this plant, " Lakes and ponds of the north woods, throughout 

 and common." I conclude, therefore, that the plant is, in this 

 region, a lake plant. 



Heteranthera dubia is a deep water plant, and grows in tliese 

 lakes as 'well as in slow flowing streams. 



The whole order Ny mphteacese is a water-loving group. With 

 rare exceptions it is confined to the shallower portions of the 

 lake. The exceptions are cases where the strong rootstock of 

 NympJisca and Castalia have persisted after the moor has ad- 

 vanced into the lake beyond them and sends up, for a few 

 years, its leaves and flowers through the thin turf. The con- 

 trast between the black mud of the moor and the pure white 

 flowers of Castalia is very striking. Brasenia purpurea, Cas- 

 talia odorata, Nymphxa advena are the representative plants. 

 The depth of water in which these plants grow ranges from 

 one to six feet, only rarely going outside these limits. 



Myriophyllum spicatum is a well-known aquatic finding a 

 place here. 



The Lentibulariaceae is represented by two species in the 

 lakes and several others in the moor. None of its species are 

 common to both lake and moor. Utrlcularia vidgaris and U. 

 minor are the lake plants. While occurring in other places, 

 they thrive particularly well in the muddy lakes surrounded 

 by moors. 



And, finally, for the order Compositse, we have, in our lakes, 

 a single representative in Bidens beckii. 



