Jennings: A Botanical Survey of Presque Isle. 353 



The y/^//«^j spreads rapidly along the wet banks and out under the 

 water by means of its strong slender rhizomes. Sometimes the plant 

 forms practically closed associations, but, usually, the plants are more 

 or less scattered in lines indicating the direction of growth of the 

 rhizome. When the sandy shore is advancing rapidly upon the water 

 of the lagoon the direction of growth of the rhizomes is very strikingly 

 inward, towards the water-line. 



Triglochin palustris appears scattered here and there in the Jiincus- 

 Eleocharis zone, sometimes becoming so prominent as perhaps to 

 merit a higher rank than principal species. It never penetrates the 

 closed Eleocharis consocies, but is sometimes mixed with the /uncus 

 halticus littoralis. 



The formation, as may be seen from the above statements, is com- 

 posed of alternating consocies which may be termed : 



The /uncus balticus littoralis consocies. 



The Eleocharis acu7ninatus consocies, 



The Eleocharis obtusa consocies. 



In the upper, dryer part of the zone, practically marking the eco- 

 tone between the Fopulus-Salix and. X\\e /uncus-Eleocharis ionwdXions, 

 is the Carex-Oederi ptnnila society, which characterizes very distinctly 

 an early summer aspect. The same area is occupied later in the 

 season by the less abundant Cyperus flavescens. 



Stage C. — Lagoons C, D, and part of G. 



(rt) Potaniogeton formation, 



(<^) Typha-Scirpus formation, 



(<:) Sabbatia- Linuni formation, 



(r/) Populus-Salix formation. 



Towards the ends of Lagoon G, which had been quite largely filled 

 with sand during 1905 and 1906, there are patches of two formations 

 not found along the sides of the lagoon, but which can be seen to be 

 replacing the /uncus-Eleocharis formation as well as occupying the 

 previously occupied shallower parts of the lagoon. These formations 

 are to be seen farther advanced and more typical in Lagoons C and D 

 (see Plate XLIII). 



Taking the formations in regular order from the center of the lagoons 

 outward, the formations of Stage C may be described ^as follows : 



