April, 1908.] 
The Vegetation of Cedar Point. 
3°5 
In the older part of this lagoon the Potamogeton Forma cion 
shows little change from its structure in the youngest part of the 
lagoon, excepting that the constituent plants are larger and more 
numerous. At the edge of the water and extending a few inches 
up onto the wee sand is a zone which may be termed: 
The Juncus-Eleocharis Formation. 
Facies: Juncus halticus. 
Eleocharis intermedia. 
Secondary Species: 
Cyperus rivularis, Roripa palustris. 
Populus deltoides, Salix cordata, 
Salix lucida. 
There is but little change in the outer Populus-Salix zone in 
this stage, aside from the further growth of the individuals and 
the appearance of occasional ruderal species. In the oldest and 
most highly developed parts of the lagoon under consideration 
the vegetation is in the beginning of what may be termed Stage 
C, with the following structure: 
Stage C. 
a. The Potamogeton Formation. 
b. The Typha-Scirpus Formation. 
c. The Salix (spp.) Formation. 
d. The Populus-Salix Formation. 
In this stage there is again little change in the Potamogeton 
Formation, but in the shallow water near the shore, and also 
taking the place of the Juncus-Eleocharis Formation on the 
wet bank at the water’s edge, there has appeared a new vegeta- 
tional structure as follows: 
The Typha-Scirpus Marsh Formation. 
Facies: Scirpus validus, 
Scirpus americanus , 
Typha latifolia. 
Secondary Species: 
Sparganium eurycarpum, 
Eleocharis intermedia, 
Sagittaria latifolia, 
Roripa palustris, 
Castalia tuberosa. 
Juncus balticus, 
Scirpus atrovirens, 
Alisma plantago-aquatica, 
Potamogeton natans, 
Among the secondary species are a few, — Alisma, Roripa, 
Sagittaria, —which are more typically representative of the humus 
swamp or marsh margin than of a beach lagoon and their presence 
here is to be regarded as due to the rather large amount of organic 
matter (drift debris) incorporated into the soil of the habitat. 
The vegetation of this formation catches considerable sand and 
contributes quite appreciably to the filling of the lagoon. 
