Hill: Penobscot Vegetation 399 



typical development. About Maces Pond in Rockport this 

 zonation of vegetation is particularly striking. In the 

 deeper water occur the submerged and floating aquatics, 

 with the water lily (Nymphaea odorata) conspicuous. As 

 we proceed shorewards this area is succeeded by a broad 

 zone of pickerel weed, bordered on its landward side by a 

 narrower one of cat-tails. A well-marked sedge stage fol- 

 lows this, consisting of Carex rostrata, Carex lurida, Scir- 

 pus atrocinctus and Calamagrostis canadensis with Sium 

 cicutaefolium, Chelone glabra and Bidens cernua as prom- 

 inent herbaceous species. A solid zone of Myrica Gale 

 makes up the shrub stage, and this in turn gives way to a 

 swamp forest in which red maple predominates with Vibur- 

 num dentatum and Sambucus canadensis the principal 

 shrubs in the undergrowth. A similar zonation on a smaller 

 scale is shown in Figure 34< which pictures a small lagoon 

 on the south side of Lake Alamoosook in Orland. This 

 area has been cut off from the larger lake by a sand bar 

 and is rapidly becoming filled with vegetation. 



Association-types of cedar swamps 



In localities which are favorable to the growth of the 

 white cedar (Thuja occidentalis) this species is apt to pre- 

 dominate in the swamp forest, sometimes to the entire ex- 

 clusion of all other trees. A cedar swamp of this nature 

 occupies an extensive area on Beauchamp Point in Rock- 

 port and may be described as characteristic. About 90 / 

 of the trees are cedars and the remainder comprise scat- 

 tered individuals of larch, white spruce, and red maple. 

 The shrubby vegetation includes : 



Taxus canadensis Hex verticil! a to 



Salix discolor Acer pennsylvanicum 



Myrica carolinensis Comus stolonifera 



Alnus incana Ledum groenlandicum 



The most striking feature of this swamp is the great pro- 

 fusion of bryophytes which not only carpet the forest floor 



