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I.Introduction II. General features of the coast of Lake Michigan. I. The ecological factors. LIGHT AND HEAT WIND SOIL WATER OTHER FACTORS. IV. The plant societies.· ATHE BEACH 1. The lower beach 2. The middle beach 3. The upper beach 4. Fossil beaches B.THE EMBRYONIC OR STATIONARY BEACH DUNES. 1. Dunes ofrapid growth (primary embryonic dunes.. 2. Dunes of slow growth (secondary embryonic dunes) C.THE ACTIVE OR WANDERING DUNES.THE DUNE COMPLEX 1. Transformation of stationary into wandering dunes 2.Physical and biological features of the dune-complex 3. Encroachment on preexisting plant societies 4. Capture of the dune-complex by vegetation D. THE ESTABLISHED DUNES 1. The basswood-maple series 2. The evergreen series 3. The oak dunes V. Conclusion VI. Previous studies of sand dune floras BIBLIOGRAPHY