Successioxal Relations of Vegetation. 



279 



The relation of this series of bog associations to those first 

 described is probably the same as the relation of the pure spruce 

 forest of the coastal strip to the interior of Nova Scotia. These 

 bogs are farther from the coast, occupy more matured and ex- 

 tensive areas, hence are richer in species. 



The Picea Formation. Throughout the rather narrow 

 coastal strip along the Bay of Fundy in southwestern Nova 

 Scotia, the black spruce forms a continuous and nearly pure 

 growth. In addition to Picea mariana one occasionally observes 

 Abies balsamea and Picea canadensis. The forest varies greatly 

 in density from an almost impenetrable thicket to an open forest 

 with abundant undergrowth This latter condition is not un- 

 likely to be attributed to man's interference. The striking fea- 

 ture of the habitat is the shallow and moist soil. Sphagnum 

 and Hypnum Schreberi occur about the bases of trees everywhere. 

 In height the trees are usually less than ten meters, and along the 

 cliffs less than half that height. The open places support lelicts 

 of the Alnus-Myrica association and some characteristic forms 

 like Phegopteiis polypodiodes, Arctostaphylos uva-ursi, Dali- 

 barda repens, Aster junceus, and Linnaea borealis. 



The succession from the marine formations through the salt- 

 marsh and bog have been outlined. Another succession begin- 

 ning with the bare locks on the headlands would lead us through 

 a lichen formation; a crevice-plant formation, made up largely 

 of the bog herbs and low shurbs already mentioned; to the alder 

 thicket and the spruce forest. 



Where the forest has been cut and burned, a secondary 

 succession is started by the coming in of Pteiis aquilina, Splidago . 

 junce a, .S^ca^ia, Hieracium scab rum, Danthonia spicata, 

 Holcus lanatus, Prenanthes trifoliata, in addition to the many 

 relict species (the Pteris-Solidago association of the Clearing 

 Formation). This may revert directly to the forest or be further 

 modified by cattle into the Pasture Formation. 



Pastures are common along the coast and are occupied by 

 the Agrostis-Festuca association. Agrostis alba and Festuca 

 _ovina are the common grasses. Juncus balticus and J. tenuis 

 dominate the wet places. The more frequent associates are 

 A9ter tardiflorus-, Euphrasia americana, Mentha arvensis cana- 

 densis, Viola pallens, and Fragaria virginiana. 



