392 PROCEEDINGS OF THE ACADEMY OF [Aug., 



The lake is almost choked with a green alga, Cladophora flavescens, 

 which has invaded the water lily associations and threatens to exter- 

 minate them. Not only that, but the lake for boating purposes has 

 been ruined by the floating masses of Cladophora which at times of low 

 water form mats of algal felt, and unless copper sulphate is used to 

 destroy this plant the lake will be converted gradually into a fresh 

 water marsh. 



The water's edge is margined generally by Panicum crus-galli and 

 Scirpus pungens, with which in close association were found, but in 

 varying abundance, Panicum virgatum, Scirpus pungens, Typha 

 angustifolia and Nympluea odorata, which formed in most places the out- 

 ward edge of this strip, growing in the shallow water in several places 

 and extending its growth out over the surface of the lake. 



The only plant of the second strip which may be said to grow in 

 pure association is Cladium mariscoides, which forms back of Panicum 

 crus-galli of the first strip a growth in some places 100 feet long, ex- 

 tending back to drier soil. Associated with this sedge grow Polygala 

 cruciata and Sabbatia angularis. The second strip, however, is charac- 

 terized by the presence of Gerardia purpurea, Rhexia rirginica, 

 Drosera linearis, D. filiformis, Fuirena squarrosa hispida, Panicum 

 virgatum, Polygonum sagittatum, Hibiscus moscheutos and Lobelia spicata. 

 In a few wet places sphagnum occurs, and here grow Vaccinium macro- 

 carpon and Drosera filiformis. 



Fresh Water Pond Formations. 



When the sand bar formed across the end of an inlet has become 

 permanent, the lake formed back of it gradually becomes converted 

 into a basin holding nothing but fresh water (instance Wreck Pond 

 in 1909, with salt marsh species), and the vegetation becomes eventually 

 that found in fresh water ponds and along their margin. Three such 

 fresh water lakes were studied carefully on the northern New Jersey 

 coast, viz. : Como Lake, a small uncharted pond back of Como Lake 

 and formerly part of it, and Silver Lake. Incidentally in this survey 

 Bradley Lake and Wesley Lake at Ocean Grove and Sunset Lake in 

 Asbury Park were visited, but it was found that the banks of 

 these lakes were sodded with cultivated grasses and planted with 

 shrubs for ornamental purposes, so that these lakes, although formed 

 in a similar manner to the ones studied, are omitted from further con- 

 sideration. 



Silver Lake.— Silver Lake is situated in the borough of Belmar and 

 is entirely surrounded by summer cottages (Fig. 5). It is less than 



