1905] TRANSEAUBOGS OF THE HURON RIVER VALLEY 447 



Primus serotina, Quercus alba, Q. macrocarpa, Acer rubrum, Betula 

 lutea, Amelanchier Botryapium, Viburnum pubescens, Spiraea 

 salicifolia, S. tomentosa, Corylus americana, Sambucus pubens, 

 Cornus candidissima, C. stolonifera, Cicuta maculata, Aster lateri- 

 florus, Carduus altissimus, Galium asprellum, Osmunda cinnamomea, 

 O. regalis, Ranunculus pennsylvanicus, Calamagrostis canadensis, 

 Viola blanda, Euthamia graminifolia, Bidens frondosa, and Aster 

 Novae- Angliae. 



Sedge society. On the northeast side of the bog is an area domi- 

 nated by sedges. In the fall of the year it appears to be a uniform 

 area of Scirpus cyperinus, but there are many other species mixed 

 with it. The substratum is low and is mainly characterized by 

 tussocks formed by the sedges. Throughout, occur small clumps 

 of the willows already mentioned. The most abundant accessory 

 species are Isnardia palustris, Calamagrostis canadensis, Carex 

 teretiuscula, C. stipata, C. filiformis, C. fusca, C. oligosperma, 

 C. riparia, and Aulacomnium palustris. 



The future flora of this bog appears to be indicated by the rapid 

 growth of the poplars, willows, and oaks. The few tamaracks 

 remaining are approaching maturity and are not being reproduced. 

 The means by which these tree species combat the shrubs is mainly 

 by shading, while the latter in the same way interfere with the develop- 

 ment of the tree-seedlings. The time involved in this struggle must 

 be very great, but the ultimate outcome will be an oak forest, the 

 intervening stages being filled in by poplar and willow growths. If, 

 however, the decay of the peat beneath these trees brings the surface 

 to the water level, the poplar-willow stage will be indefinitely pro- 

 longed. 



GENERAL CONSIDERATION OF THE BOG FLORA. 



Beside the trees mentioned in the preceding descriptions, note 

 should be made of the occasional occurrence of the black ash, Fraxinus 

 nigra, and swamp white oak, Quercus platanoides, in bog areas. It 

 frequently happens, when the tamaracks are cut, that the black ash 

 becomes abundant, as in the area one-half mile southeast of Kava- 

 naugh Lake, where it is now associated with Ulmus americana and 

 Acer rubrum. Another example occurs about a mile north of Chelsea 

 in the NE. ^ Sec. i, Sylvan Tp. Here in a small area from which 

 the tamaracks were removed, Fraxinus nigra, Quercus platanoides, 



