Jennings : A Botanical Survey of Presque Isle. 383 



A. — The Marsh. — This habitat comprises those shores exposed 

 to the waves, but having usually shallow water and a gently sloping 

 sandy or gravelly bottom. 



B. — The Cove. — The cove habitat comprises the indentations of 

 the shore line — coves, bays, etc. — which are generally well pro- 

 tected from wave action and have deeper water than the marsh. 



C. — The Driftwood Habitat. — This habitat comprises those shores, 

 which are so situated with respect to wind and current as to be sub- 

 jected to the accumulation of driftwood. 



The Marsli Habitat. 



This habitat is represented along a large part of the shore of the 

 bay. The vegetational structures along the narrow neck of the penin- 

 sula near the Head, enumerated from the water to the shore, are as 

 follows : 



(a) Scirpus Formation, 



(/^) Salix discolor-lucida Formation, 



(r) Solidago-Meiboviia Formation. 



The Scirpus Formation. 



The Scirpus formation consists of the two facies, Scirpus validus 

 and Scirpus americanus. The former species constitutes the advance 

 guard and frequently occurs far out in the bay, where the water is six 

 feet or more in depth. The Scirpus atnericanus consocies, however, 

 occurs nearer the shore, and, as in the recently formed lagoons at the 

 eastern end of the peninsula, it may occur even on the beach several 

 inches above the ordinary water-line. 



This formation is evidently of considerable importance in deter- 

 mining what the contour of the shore shall be, both from the protec- 

 tion it affords the shore, and from the part it plays in the actual out- 

 building of the shore. The plants have strong rapidly-growing root- 

 stocks, and, once having accomplished ecesis, families and communi- 

 ties are soon formed. The slender wiry stems and leaves bend with 

 the wind and wave and are rarely broken, even in the most severe 

 storms. With the formation of ecological families and communities 

 the rushes, growing thickly together, act as an impediment to drifting 

 sand and the bottom is thus sometimes built up quite rapidly where 

 otherwise the sand would not have come to a permanent rest. The 

 bottom is thus built up not only in the area actually occupied by the 



