138 ROYAL SOCIETY OF CANADA 



mountains, are islands on which colonies of northern species are able to 

 survive amidst more southern forms, and the more northern any species 

 are. the wider in general is their circumpolar range. 



2nd. The resemblances consist in the presence in both, of species of 

 northern range native to both countries (species of Sphagnum, Erio- 

 phorum vaginatum, Sch'pus cœspitosus, Rubus Chamœmorus, Andromeda 

 polifolia, Empetrum nigrum, Vaccinium Oxycoccus and Vitis-Idœa), and 

 also in the presence of others which are representative, as Ledum lati- 

 folium vs. palustre ; Vaccinium cœspitosus, Canadense and Pennsylvani- 

 cum vs. Myrtillus. It is remarkable that Sphagnum cymbifolium and 

 Vaccinium uUginosum, both of which occur in this country, have not 

 been seen in the three bogs I have studied, i/ut further search ma}' reveal 

 them. 



3rd. The dirterences consi.st chiefly in the absence from the bogs of 

 each country of genera and species not native to it. and their replace- 

 ment by native species of rather more southern range than the species 

 common to both (Galluna vulgaris, Erica Tetralix, Pinus pumilio and 

 ^alix repens, and others, less common, in Europe, vs. species of Kalmia, 

 Cassandra, Gaylussacia, Larix Americana and Picea nigra) ; and in 

 the extreme development of some species in our bogs {Empetrum) 

 allowed by the absence of ecologically' similar forms, {Calhina^), as will 

 later be discussed along with other related questions connected with the 

 ecological characteristics of the vegetation of the bogs. 



The grouping or association of these plants as they occur in the 

 Lepreau bog. which is a type of them all, is thus : — Nearly all around the 

 bog is a low, dense spruce forest, with bushy undergrowth, which the bog is 

 overwhelming ; at the line of contact the trees are dying and the branches 

 ■die from below upward, until often only a gi-een tuft remains above. 

 From the forest the steepest slopes of the bog rise, on which the trees and 

 bushes become generally smaller, until,, when the high part is reached, 

 they are few and dwarfed to a few inches in height. Where the bog, how- 

 ever, comes in contact with a steep land slope, there is between the two a 

 strip about five to eight yards wide of ver}- wet bog, in the lu-ight red 

 moss of which grows luxuriantly Smilacina trifoUa. Sarraeenia. Arethusa 

 and other Orchids, etc' 



The high part of the bog is made up of nearly pure Sphagnum bear- 

 ing the scanty dwarf trees and shrubs, and it is these two characters, the 

 pureness of the moss, and the great dwarting and scantiness of the woody 

 plants, which in combination with the rai.sed form, distinguish the raised 

 from the flat bogs. The surface of the moss forms rounded hummocks 

 and hollows, with radii averaging about a foot or less. The hummocks 

 are of Sphagnum fuscum., which grows in such rounded radiating masses 



1 1 do not find in these bogs as definite a zonal arrangement as MacMillan (13b) 

 describes for the Muskeag areas of Minnesota. 



