MacMillan : shores at lake of the woods. 987 



7. Mixed shrubby back strand: Irregularity of surface 

 contour, strong wind currents, differences in soil fertility be- 

 tween adjacent limited areas. 



8. Coniferous arboreal back strand: Low, dry, irregular 

 surface, deep sterility of soil, slight wind currents. 



9. Populus arboreal back strand: Low, nitrogenous, not 

 inundated, regular contoured, sheltered areas. 



10. Salix arboreal back strand: Low, moist, nitrogenous, 

 inundated, sheltered shores without coniferous formations im- 

 mediately behind. 



11. Quercus arboreal back strand: Low, rounded, nitro- 

 genous, wind swept shores of regular contour. 



12. Mixed arboreal back strand: Irregular fertile shores 

 not sharply distinguished from the back country by definite 

 topographical outlines. 



While the discussion of the back strand formations has been 

 suggestive rather than exhaustive enough has been brought 

 forward to indicate the strong dependence of the vegetation- 

 groups upon the environmental conditions. Indeed a catalogue 

 of the individual plants of a given area of definite size, with in- 

 formation of the habit of the plant individuals, whether they 

 were shrubs or trees, would almost enable one to plat the 

 topography of the area, provided it was selected within some 

 such field of previous observation as in this instance, Lake of 

 the Woods. 



Strand-pools. There are three types of strand- pools at Lake 

 of the Woods. They are : 



1. Pools of the front strand. 



2. Pools of the mid-strand. 



3. Pools of the back strand. 



These are of different methods of formatiou, of different dur- 

 ation and characterized by plant populations which are to some 

 extent distinctive. 



I. Pools of the front strand have already been discussed 

 under the general caption of Front strand. They are formed 

 solely by the action of surf and are of short duration. 

 Their plant population consists therefore, only of lowly algae 

 that are brought into them by the accession of water from the 

 lake and eventually each of these pools will evaporate and 

 during the next heavy surf, new ones will be formed, to dis- 

 appear in their turn. In such pools the principal inhabitants 

 at Lake of the Woods are Cyanophyceae of the genera 

 Aphanizomenon, Anabaena, Nostoc, Oscillatoria and Lyngbya. 



