Mac.Millan : shores at lake of the woods. 969 



STRAND. 



Front strand. — The zone of vegetation denominated front 

 strand, is that group of plants established nearest the water's 

 edge. Between the mid-strand group and the water of the lake 

 is a narrower or wider strip upon which vegetation is unable 

 to establish itself, except in the case of the lower plants such 

 as Aphanizomenonflos- aquae, for example. The width of the barren 

 strip depends upon the force of the surf. In this area small 

 strand pools, tenanted by algae in some cases, will form be- 

 tween successive seasons cf surf-impact. The transitory pools 

 can furnish an area for the development only of very simple 

 and short-lived organisms. Various species of algae may com- 

 plete their reproductive processes in such pools of the front 

 strand and the region of the beach closest to the water's edge 

 must be regarded as occupied by an interrupted zone of algal 

 forms. In some cases after a heavy wind such pools will be 

 crowded with Cyanophyceae to such an extent as to make the 

 zone exceedingly conspicuous, but after a few days of sunshine 

 and surflessness the pools will evaporate, and the spores alone 

 of the algae will retain their vitality. Some of these spores 

 will be washed out into the lake with the next season of surf, 

 while the majority will be buried in the sand. The pools of 

 the front strand are therefore characterized by a special vege- 

 table formation, transitory as is its habitat and of lowly types. 

 In high surf these algae contribute to the nitrogenous content 

 of the mid-strand. 



Mid-strand. — Extending from the front strand near the wat- 

 er's edge back to the higher beach upon which the surf never 

 dashes, is commonly a shelving area bearing a very character- 

 istic group of plants. Its breadth varies with its inclination, 

 its texture, the strength of the surf and the character of the 

 bottom off-shore. This area is at long intervals subjected to 

 strong spray or even light surf and to occasional inundation. 

 Such an exposure may not arise for several seasons and, when 

 it comes, depends upon unusual height of water and continuous 

 winds. Hence a group of plants, very many of which are an- 

 nual, although some are perennial, establish themselves upon 

 the strip. This band of occasionally inundated beach may be 

 known as mid- strand. It is characterized by relatively scanty 

 and dwarfed development of trees or shrubs except in the case 

 of such as bear with ease submersion for a season — as for ex- 

 ample, Salix, Cornus, Primus pamila, Poptulus tremuloides. 



