903] TRANSEAU—BOGS OF THE HURON RIVER VALLEY 443 
the appearance of an elongated brown rosette about the stem bases. 
Clitocybe laccata and Boletinus porosus are also abundant in the 
autumn. The partially decayed stumps bear Peltigera canina. 
Other species occur in this area, but reach their dominance in the 
next society. 
Poplar-maple society—Here are brought together the remnant 
of the bog species, and those more characteristic of swamps and 
clearings. The trees are mainly Populus tremuloides, with a scat- 
tering of Acer rubrum. Elm seedlings occur. The shrubby plants, 
however, make up the bulk of the vegetation. TIlicioides mucronata, 
Ilex verticillata, Aronia nigra, and Vaccinium corymbosum have 
almost complete possession, and are struggling with one another for 
space. All these forms send up stems from the underground parts, 
so that among them the struggle is largely a mechanical one. How- 
ever, where the red maple overtops them, the factor of shade enters, 
and the black choke-cherry and high-bush blueberry are the most 
tolerant. The mountain holly and black alder prevail elsewhere. 
The next most important plants are the willows, Salix sericea and 
S. discolor. Mixed with these are Cornus candidissima, Rubus 
nigrobaccus, Rosa Carolina, Cornus stolonifera, Spiraea salicifolia, 
and Rubus strigosus. 
Willow-sedge society.—The area dominated by these plants is 
_ Covered with water in the spring and during moist weather. Although 
this Society is fast being crowded out by the next preceding, it is 
Probable that only a small part of that area was ever occupied by these 
Plants. These plants require a more moist substratum. The domi- 
hant species are Salix sericea, Carex riparia, C. stipata, Cornus 
Stolonifera, and Osmunda cinnamomea. In the case of the cinna- 
Mon fern found in this bog there is a remarkable development of 
aerial roots. They are about an inch long and extend outward from 
the thick rootstock in all directions, forming a dense covering. The 
Toots are thickly covered with root-hairs which have been persistent 
= least through one winter. The root-hairs are large and brown 
| Moolor. The appearance of these rootstocks, as a whole, Is very 
“uggestive of certain tropical tree ferns. The other species present 
are Ranunculus abortivus, Polygonum sagittatum, Cicuta bulbifera, 
Prunella vulgaris, Rubus americanus, Rhus. Vernix, Solanum dulca- 
