1905] |TRANSEAU—BOGS OF THE HURON RIVER VALLEY 433 
for the most part, of Salix Bebbiana, S. discolor, S. sericea, Cornus 
candidissima, Acer rubrum, and Ulmus americana. Beside the 
many plants of the sedge-grass society which remain as relicts, the 
accessory species include Rosa Carolina, Impatiens biflora, Sambucus 
pubens, Spiraea salicifolia, Prunus serotina, Quercus alba, Q. 
velutina, and Opulaster opulifolius. These trees grade into the 
forests of the upland and establish a natural order of succession. 
An interesting comparison is afforded when we note the species 
dominant along the western or bog margin. Here the outer zone of 
aquatics is made up of the same species, but this substratum is a 
floating raft constructed by the plants themselves. Without again 
enumerating the species, we pass to the society which closely follows 
their development. 
Bog-sedge and shrub society.—This society forms a very complex 
gowth, averaging so feet (15 ™) in width. On the lakeward side are 
the aquatics; on the other, the growth of tamaracks. The sedges and 
shrubs are not separable, as in many other localities. Carex fili- 
formis is by far the most important plant in the society. Its vigorous 
Production of rhizomes and roots especially fit it for the position which 
occupies. Certain other plants are locally abundant and of great 
Consequence. These include Dryopteris thelypteris, Menyanthes 
infoliata, Eleocharis palustris, Comarum palustre, Sagittaria latifolia, 
Eriophorum polystachyon, Carex teretiuscula, Typha latifolia, Salix 
myrtilloides, S. candida, Betula glandulosa,° Oxycoccus macrocar- 
Pus, and Andromeda polifolia. As accessory species may be mien: 
tioned Salix discolor, S. Bebbiana, Cicuta bulbifera, Cardamine 
Pratensis, Chamaedaphne calyculata, Campanula aparinoides, Rumex 
Britannica, Epilobium adenocaulon, Asclepias incarnata, Pogonia 
0phioglossoides, Blephariglottis blephariglottis, Limodorum auc : 
Sum, Marchantia polymorpha, Aulacomnium palustre, Sarracenia 
Purpurea, Drosera rotundifolia, Boehmeria cylindrica, Carex somone 
. hystricina, Cornus stolonifera, Parnassia caroliniana, Viola blanda, 
om Penthorum sedoides. Here and there occur young tamaracks 
Which by their growth inaugurate the next society. 
Tamarack societ y.—As development proceeds, 
osely to this species than 
the shrubs and 
6 
os The form found here and at Delhi corresponds more cl 
‘ Pumila, but its characters are intermediate. 
