412 Proceedings Portland Society Natural History 



have already been described (page 372). Naturally in all 

 such localities aquatic species are absent and the pioneer 

 vegetation usually consists of grasses and sedges. 



The amount of water present determines the nature of the 

 first association-type to occupy the area. Where it is inun- 

 dated for a considerable period or the supply of seepage wa- 

 ter is very plentiful a marsh or open swamp results (Figure 

 •10). The characteristic species in such a locality are: 



Onoclea sensibilis 

 Poa triflora 

 Glyceria canadensis 

 Scirpu s georgia n u s 

 Scirpus rubrotinctus 

 Scirp u s eyperinus 

 Car ex crinita 

 Car ex stipata 

 Carex In rid a 

 J uncus effusus vars. 

 Senecio Robbinsii 



Iris versicolor 

 Polygonum sagittatum 

 Thalictru m polyga mu m 

 Ca rda m ine pen nsylvanica 

 Impatiens biftora 

 Epilobiu m densu in 

 Cicuta macula t a 

 Mentha arvensis 

 Chclone glabra 

 E u pa t o ri u >n pe r folia t u m 

 Eu pa to ri it m p u rp u re u m 

 var. maculatum 



Carex stricta is occasionally present along streams (Fig- 

 ure 41), but this species, so characteristic of open swamps 

 in other regions, is of little ecological significance here. 

 The distribution of Scirpus rubrotinctus and the Joe-Pye- 

 Weed (Enpatorium purpureum var. maculatum in the Pe- 

 nobscot Bay region is interesting and suggests that of the 

 buck-bean mentioned above (page 394). These species are 

 extremely abundant on the western shores of the Bay, oc- 

 curring in almost every swamp, while they are practically 

 absent from the eastern side. 



In situations where the plants of the spring swamps are 

 free from inundation, save in the early spring, and the 

 ground is fairly dry during the rest of the growing season 

 a dense, turf -like vegetation develops. These "swales" are 

 characterized by the dominance of grasses and sedges of a 



