April, 1908.] 
The Vegetation of Cedar Point. 
3°9 
In the course of time the soil may have accumulated to such an 
extent that the shallower water may offer conditions suitable 
for other species than those of the resident formation and, by 
invasion and ecesis, another formation may eventually occupy 
the habitat. In the Lily Pond the formation next outside of the 
lily zone is the following: 
The Decodon-Persicaria Formation. 
Facies: Decodon verticillatus, 
Persicaria lamina. 
Secondary Species: 
Naumbergia thyrsi flora, Alisma plantago-aquatica , 
Solanum dulcamara, Cephalanthus occidentalis, 
Pontederia cordata, Sagittaria latifolia, 
Nymphaea advena. 
Further study of this formation might, perhaps, result in the 
placing of Persicaria lamina as a principal species, but it probably 
is best regarded as one of the facies. The Decodon-P ersicaria 
Formation forms soil quite rapidly and upon the emergence of the 
soil above the ordinary water level the following structure takes 
possession: 
The Cephalanthus-Cornus Thicket Formation. 
Facies: Cephalanthus occidentalis, 
Rosa Carolina, 
Cornus stolonifera. 
Secondary Species: 
Salix lucida, 
Salix cordata, 
Latliyrus palustris, 
Typha latifolia, 
Persicaria lamina, 
Alisma plantago-aquatica 
Scirpus americana, 
Eleocharis intermedia, 
Calamagrostis canadensis, Latliyrus palustris. 
Towards the southern end of the pond there is a patch of wet 
meadow constituting a remnant, probably, of a once somewhat 
larger Calamagrostis Wet Meadow Formation. The latter for¬ 
mation is represented on Presque Isle by the strong Cladium- 
Calamagrostis Wet Meadow Formation, w T hich, on lagoon banks 
with gentle slopes and correspondingly wide habitat zones, con¬ 
stitutes an important formation following the rushes and preced¬ 
ing the thicket stage . Cladium does not appear on Cedar Point 
but the Calamagrostis canadensis Wet Meadow Formation, really 
a consocies only of the northward-ranging Cladium-Calamagrostis 
formation, is well developed in the Cedar Point marsh succession 
and will be discussed further under that head. 
In the Cephalanthus-Cornus Thicket Formation there is 
usually more or less of a mixture of the facies but sometimes a 
more definite structure is evident. Where there is a segregation 
