200 BOTANICAL GAZETTE [MARCH 
map (fig. 36) and in the general view (fig. 37). Certain features 
of the succession were so well developed in this bog that they must 
have a place in this account. 
The sedge mat is composed almost entirely of Carex limosa L. 
(mud sedge) (fig. 38). Occasional bare muddy spots are nearly 
free of sedge, but support a scattered growth of Menyanthes and 
Drosera anglica Huds. (narrow-leaved sundew). These appear to 
represent the youngest stage now existing in this habitat. 
Fic. 37.—Raspberry Island bog: general view; sedge zone of Carex limosa type 
in the scensolitide the sphagnum-shrub society occupies most of the view; young bog 
trees as pioneers of the forest; black spruce prominent in the bog forest. 
a) The sphagnum and its relations 
Particular attention was given to the sphagnum, which is very 
luxuriant in this bog; especially to its point of origin, the conditions 
governing its spread, and its relations to companion species. 
The first point to be noted is that the sphagnum is a superficial 
layer supported upon the sedge mat, and thus does not contribute 
in any large degree to peat formation. This feature has been 
noted by Hott (33) for the Isle Royale bogs, and by TRANSEAU 
(56) and Davis (19) for the northern and southern peninsulas of 
Michigan. 
