5cm.- 



JSOOft, 



FIG. 288. Diagram illustrating zonation and succession around a pond 



I, pond (a, floating pipewort (Eriocaulori) b, deepest portion of pond ; c, rushes 



(Juncus) forming an association) ; II, bog zone ; ///, swamp thicket zone ; IV, sand 



pit and incomplete xerophytic zone ; V, dry meadow zone ; VI, dry woodland zone 



(d, birch woodland). From Bergen and Davis's " Principles of Botany " 



