324 



The dense growth of this association aids very materially in 

 building- up the sloughs, after which it is replaced by other associa- 

 tions that would otherwise have been unable to develop. 



UST OP THE SPECIES OE THE MENYANTHES-SAGITTARIA ASSOCIATION 



Dominant Species 

 Menyanthcs trifoliata 

 Sagittaria latifolia 



Secondaiy Species 

 Utricularia vulgaris aiiiencona 

 Polygonum amphibium 



hartivrightii 

 Lysiniachia thyrsiflora 

 Acorns calaimis 

 Proserpmaca palustris 

 Polygonnm muJiIenbergii 



Relic Species 

 Nyniphaca adzvna 



Invading species 

 Car ex lamiginosa 

 Hypericum virginicuin 

 Bidens tricliospcrma tenniloha 

 Iris versicolor 

 Asclcpias incaniafa 



Potentilla palustris 



Scutellaria galericulata 

 Alisuia plantag o-aquatica 

 Oxy polls rigidior 

 Polygonum hydro piperoides 

 Ludzdgia palustris 

 Sagittaria heterophylla rigida 

 Veronica anagallis-aquatica 



Ranunculus delphinifoliiis 



Scirpus Huviatilis 

 Scirpus atroznrens 

 Spartina uiicha uxiana 

 Cephalanthus occidentalis 

 Penthorum scdoidcs 



THE CAREX ASSOCIATION 



In the bogs, al)0\'e the Menyanthes-Sagittaria association, occurs 

 a sedge association composed almost entirely of species of Carex. 

 The sedges grow quite densely, and while above the surface of the 

 water the culms seem to'be regularly distributed, beneath the surface 

 they are found to be grouped together in bunches or hummocks. If the 

 water-level is lowered, this gives rise to the hummocks, which are 

 so characteristic of boggy shores. The bottom is decidedly muddy, 

 and the water is shallower than in the two preceding associations. 

 The sedges afford good hiding places for several of the marsh birds 

 and other animals. 



There are seldom any secondary species with the sedges. In 

 the bogs, Utricidaria znilgaris americana and Iris versicolor have 



