434 BOTANICAL GAZETTE [DECEMBER 



disturbed that on the western side the area of cassandra-sphagnum 

 dominance is very irregular. On the eastern side this plant society 

 is in the last stage of its existence. The intimate association of 

 Chamaedaphne calyculata, Sphagnum cymbifolium, S. subsecun- 

 dum, and S. recurvum is well illustrated here. The plants occupy 

 the whole of the territory where they flourish. The other species 

 are decidedly secondary. It is to be further noted that in the com- 

 petition with the sedge species these plants actually override them, 

 and only an occasional Eriophorum virginicum survives. The 

 water- conserving properties of the sphagnum are too well known to 

 need description here. But the mutual advantage of the cassandra- 

 sphagnum combination is worthy especial note. The former by its 

 numerous branches furnishes a framework which aids in the upbuild- 

 ing of the moss and in shading. The sphagnum, on the other hand, 

 furnishes a moist cover in which the conditions for the shrub are most 

 favorable. 



The accessory species include the moss, Aulacomnium palustre; 

 the herbs, Drosera rotundifolia, Arethusa bulbosa, Habenaria lacera, 

 Sarracenia purpurea, Pogonia ophioglossoides, Limodorum tubero- 

 sum, Viola blanda, Osmunda regalis, Campanula aparinoides, 

 Scutellaria galericulata ; and the shrubs, Andromeda polifolia, 

 Betula pumila, Oxycoccus macrocarpus, O. Oxycoccus, Aronia 

 nigra, and Ilicioides mucronata. 



Tamarack society. Among the cassandra occur many young 

 tamaracks, and these by their development come to overshade the 

 shrubs and form the tree society of the bog. The dead remnants of 

 the cassandra mounds make up a large part of the floor beneath them. 

 The species of secondary importance are Ilicioides mucronata, 

 Aronia nigra, Chamaedaphne calyculata, Osmunda cinnamomea, 

 O. regalis, Dryopteris spinulosa intermedia, D. cristata, Poly tri chum 

 juniperinum, Plagiothecium denticulatum, Thuidium recognitum, 

 Aulacomnium palustre, Marchantia polymorpha, Sphagnum cymbi- 

 folium, Boletinus porosus, and Thelephora intybacea. 



The tamarack zone has been much disturbed by clearing and 

 burning. At the present time a large part of the area on the south- 

 west side is dominated by other tree species. Some of the plants of 

 the clearing have spread into the pure tamarack growth. 



