Jennings : A Botanical Survey of Presque Isle. 365 



of the small ponds has an area of Nymphcea with a few Potamo^etons 

 still remaining ; outside of this being a zone consisting of the Typha 

 latifolia consocies of the Typha-Scirpus formation. 



Surrounding the zone of T)^^/;^! is the Cladiuvi-Calamagrostis for- 

 mation, which in several places is a number of rods wide, and in fact 

 occupies a large part of the lagoon. There is a very marked segrega- 

 tion of this formation into zones ; an inner one consisting of the 

 Cladium mariscoides consocies, and an outer one consisting of the 

 Calamagrostis canadensis consocies. The latter presents a very beauti- 

 ful Aster ericoides aspect during late September. 



The Fragaria-Polytrichum Formation. 



At the outer border of the Cladiuvi-Calajnagrostis meadow appears 

 a rather broken zone, characterized by Polytrichuvi and Fragaria. 

 This formation appears to be a sort of " filler" between the meadow 

 and the succeeding shrub-zone. The old shore of the lagoon is here 

 rather wide and has almost no slope, and the Fragaria- Polytrichum 

 formation appears only where there seems to be a space, which cannot 

 be occupied by the shrub-zone by the time that the conditions have 

 become more or less unsuitable for the Ca/ajnagrostis canadensis 

 consocies. 



The typical composition of the formation is : 



Fades. — 



Fragaria virginiana, Polytrichum sp. 



Secondaty Species. — 



Sphagnum sp. , Aster ericoides, 



Rhus typhina, Alnus incana, 



Salix cor data. 

 This formation is probably a further development, in conditions of 

 a soil with more humus, of what was termed in the Cladium- Calama- 

 grostis formation of Stage F, the Fragaria society. A further develop- 

 ment of probably the same structure is the Aronia-Polytrichum forma- 

 tion skirting the Sphagnum- Oxycoccus formation of Cranberry Pond and 

 of which more will be said later. It appears probable that the Fra- 

 garia-Polyij-ichum formation is not necessarily a member of the 

 lagoon-marsh-thicket-forest succession, but that it represents, either 

 in whole or in part, a formation belonging essentially to some other 

 succession, having found between the meadow and the shrub-zones 

 certain conditions suitable for its successful intercalation. More will 



